Journal of microbiology, biotechnology and food sciences

QUALITY EVALUATION OF DEVELOPED IRON AND RETINOL ACETATE FORTIFIED YOGURT

Bhawana Sachdeva — 2024-07-15

Yogurt is one of the most nutritious probiotic food and serves as a medium for nutrients supplementation. The prevalent deficiency of iron and vitamin A within the population prompted the creation of retinol acetate and iron-fortified yogurt. In the yogurt-making process, temperatures typically remain below 100°C for 5 to 10 minutes, and the fortified milk exhibited remarkable heat stability, surpassing even the effects of sterilization treatment (140°C for over 20 minutes). Sensory evaluations of the fortified yogurts yielded scores comparable to the control yogurt. The fortified variety set in a similar time frame, and the quantity of microorganisms used in the inoculation mirrored that of the control yogurt. Acetaldehyde, a key flavoring compound, was produced in a similar manner to the control yogurt (p>0.05). Physico-chemical properties of the fortified yogurt closely resembled those of the control, with improvements seen in viscosity and textural attributes, though these values were statistically similar (p>0.05). The fortified yogurt demonstrated stability along with consistent quality, texture, and sensory appeal, suggesting its potential for commercialization to address nutrient deficiencies.

IMPACT OF ENRICHED CO2 IN MODIFIED ATMOSPHERE PACKAGING ON THE PRESERVATION OF “PALMARITAS” STRAWBERRIES AND THE EXTENSION OF THEIR SHELF LIFE

Yousra Zantar — 2024-08-14

This study evaluated the effect of modified atmospheres (MAPs) with low oxygen levels (2.5%) and high carbon dioxide levels (from 5 to 20%) on strawberries. During 12 days of storage at 4°C, various quality and chemical content parameters were evaluated. These including decay, color, weight loss, firmness, total soluble solids, total polyphenols, anthocyanins, and flavonoids, as well as antioxidant capacity and individual phenolic compounds (quercetin, caffeic acid, gallic acid, (-) epicatechin, and p-coumaric acid). Results showed that high CO₂ levels had a positive impact on strawberry preservation: weight loss was reduced, anthocyanin content increased, decay and softening were significantly reduced, and vitamin C content was maintained. At the same time, these high concentrations of CO₂ did not affect sugar content, color, antioxidant capacity, total phenolic compounds, or total flavonoid compounds of strawberries. A storage time of 12 days at 4°C, under MAP with an initial gas condition of 2.5% O₂ + 15% CO₂ + 82.5% N₂ or 2.5% O₂ + 20% CO₂ + 77.5% N₂, was found to be ideal for preserving the quality of fresh strawberries.

OPTIMIZATION OF CARBOXY METHYL CELLULASE PRODUCTION BY CLADOSPORIUM SP. WITH FOOD WASTE IN BAGASSE SOLID STATE FERMENTATION USING RESPONSE SURFACE METHODOLOGY

Ramamohan Poludasu — 2024-07-16

Enzyme production costs should be reduced by using inexpensively available substrates. In this, we determine the effects of various medium components and food processing waste on Cladosporium sp. production of CMCase in SSF. Five factors were tested with a three-level Box-Wilson factorial, central composite design (CCD) to determine how they impacted Cladosporium sp. NCIM 901's ability to produce CMCase. For the model, the R² (coefficient of determination) value was 0.9349. Based on the process findings, the optimal medium for higher enzyme synthesis had wheat bran (4 g/L), cacl₂ (2 g/L), urea (7.5 g/L) and rice bran (8.76 g/L), with the medium's original pH at 5.5. The model's accuracy is confirmed by the experimental result of CMCase, which is 23.42 U/gds and equivalent to the expected yield of 22.31 U/gds. The accuracy of the current experimental design has been verified by experimental validation. The enzyme's properties indicated that its greatest activity occurred at pH 5.5 and that its ideal temperature was about 50 °C. The enzyme is more active toward CMC and less active toward filter paper. CaCl₂and MgCl₂ increased the enzyme's activity. Enzymatic hydrolysis of waste-derived polysaccharides into simple sugars is necessary for the industrial manufacture of bioethanol. The efficacy of the produced Cladosporium sp. cellulase (CMCase) enzyme to saccharify pearl millet grass results shows that H₂SO₄ treated substrate gave more fermentable sugars compared to the untreated substrate. Results suggest that the indigenous produced-CMCase can be efficiently used for lignocellulosic biomass saccharification (55.40%) compared to the untreated sample (37.10%) in 48 h, which will eventually reduce the cost utilized for purchasing commercial enzymes.

THE EFFECT OF BARRIER TECHNOLOGIES ON THE CHEMICAL, NUTRITIONAL, SENSORY, AND MICROBIOLOGICAL QUALITY OF ARBUTUS UNEDO L. FRUITS DURING STORAGE

Badreddine EL MEJHED — 2024-07-02

Arbutus unedo L. is a widespread tree known for its nutritional and antioxidant importance. However, the utilization of its berries remains limited due to their sensitivity and damage during storage. This study aims to evaluate the effect of barrier technologies with the addition of lemon juice (Citrus limon) and bitter orange juice (Citrus aurantium) as additives on the sensory, nutritional, and microbiological quality of fruits during storage. The combined fruits exhibited a significant decrease in pH (from 5.07±0.23 to 3.45±0.34 for fruits combined with bitter orange juice and from 5.07±0.23 to 3.64±0.12 for fruits combined with lemon juice), moisture content (from 62.48±2.32 to 45.47±3.54 for fruits combined with bitter orange juice and from 62.48±2.32 to 51.4±3.12 for fruits combined with lemon juice), and showed inactivation of aerobic mesophilic bacteria compared to non-treated fruits. Differential thermogravimetric analysis (DTG, DSC) demonstrated that fruits conditioned in the presence of bitter orange juice preserved their nutritional quality (vitamins B2, B6, B9, B12, and C) under light and oxygen exposure. The combination of acidity and sweetness improved the sensory quality of the combined fruits during storage.

CONTROL OF LISTERIA MONOCYTOGENES AND STAPHYLOCOCCUS AUREUS IN MEAT AND MEAT PRODUCTS BY CELL-FREE SUPERNATANT OF BREVIBACILLUS LATEROSPORUS BGSP7 AND BGSP9

Nemanja Mirkovic — 2024-09-19

The presence of pathogens in food has increased awareness of food safety, but it also causes large economic losses. Fresh meat and meat products contain a sufficient quantity of proteins, lipids, water, and a favorable pH that stimulates the growth of various microorganisms, including pathogens.

The aim of this study was to investigate the efficacy of Brevibacillus laterosporus BGSP7 (CFS-BGSP7) and BGSP9 (CFS-BGSP9) cell-free supernatants in the control of Listeria monocytogenes and Staphylococcus aureus in raw meat and meat products.

Raw meat and meat products were sliced and then aseptically treated by immersion for 2 minutes into solutions containing: i) CFS-BGSP7; ii) CFS-BGSP9; iii) no treatment. The samples were then artificially contaminated with: Group I – L. monocytogenes (~4 log cfu g-1); Group II – S. aureus LMM322 (~4 log cfu g^-1). Each sample was individually aseptically vacuum-packed and stored at 4°C for 8 weeks. The number of surviving bacteria in the samples were analyzed immediately after contamination with L. monocytogenes and S. aureus and at regular time-intervals: after 1, 3, 5 and 8 weeks of storage at 4°C.

Meat samples treated with CFS-BGSP7 and CFS-SP9 showed a significant decrease in the cell counts of L. monocytogenes and S. aureus. When meat samples treated with CFS-BGSP7 and CFS-BGSP9 are compared, the results show a more intense reduction rate of both L. monocytogenes and S. aureus in all samples treated with CFS-BGSP7.

DETERMINATION OF THE OPTIMAL FERTILIZATION RATE BY A NEW BIOORGANIC FERTILIZER TO ENHANCE THE GROWTH PARAMETERS AND NUTRITIONAL QUALITY OF RED BEETROOT (BETA VULGARIS L. SSP. VULGARIS)

Khadija Atfaoui — 2024-08-14

The goal of this study was to investigate the effect of different rates of a new bioorganic fertilizer and an inorganic fertilizer on the parameters growth and the nutritional quality of red beetroot.

A field trial was conducted using the randomized complete block design with six treatments and six replications: (T1= inorganic fertilizer, NPK 20-45-25 ha⁻¹, T2= Bio-Organic Fertilizer “BOF” at 10%, T3= BOF at 20%, T4= BOF at 30%, T5= BOF at 60% and T6= unfertilized control). The total carbohydrate, protein and nitrate content of harvested red beetroot was measured analytically. Quantification of betanin was determined spectrophotometrically, while the antioxidant activity assessed free radical scavenging activities against DPPH.

Statistical analysis of soils treated with 20 and 30% BOF showed similar results for the total weight of red beetroot and the weight and diameter of their bulbs. However, these treatments significantly (p < 0.05) increased the betanin content of red beetroot by 16 % compared to the conventionally grown samples. However, the investigation of the effect of the different rates of BOF on the IC₅₀ value showed a decrease of up to 52% in favor of the T5 treatment compared to the inorganic fertilizer. In contrast, organically and conventionally growing red beetroot had similar average nitrate levels.

In light of the crucial role of BOF rates, high levels of macro and micronutrients in the soil negatively affect all quality parameters of red beetroot.

FATTY ACID PROFILE OF COMMON CARP (CYPRINUS CARPIO) AFTER ADDITION OF ASTAXANTHIN TO THE FEED MIXTURE

Peter Herc — 2024-07-08

Astaxanthin is a very strong antioxidant typically fed to rainbow trout mainly to alter the color of its’ meat to red. In our study, we incorporate a relatively low concentration of astaxanthin into the diet of common carp to enhance the chemical parameters and oxidation stability of carp meat without altering the typical coloration of meat. Also, we observed the fatty acid profile of reared fish. We observed an increase in protein content in animals with astaxanthin dietary addition. It was not statistically significant, but we observed a lowering of fat content in experimental groups. Regarding lipid oxidation, we did not observe any significant effect of astaxanthin on malondialdehyde production in samples. Fatty acid profiles were determined by gas chromatography and then compared. Only significant differences were observed in stearic and arachidonic acid and in the experimental group with lower astaxanthin addition. Our results conclude that dietary astaxanthin has no adverse effect on fatty acid profile or oxidation stability during storage (at -18 °C). On the other hand, astaxanthin has the potential to enhance the protein and lower the fat content, even in low concentrations.

EFFECT OF SELECTED NATURAL EXTRACTS ON ANTIOXIDANT PROPERTIES AND SENSORY QUALITY OF VARIOUS CEREAL PRODUCTS

Tatiana Bojňanská — 2024-09-16

The aim of this study was to observe antioxidant properties as well as possible changes in sensory quality of selected bakery products after their enrichment with chosen natural extracts. Four types of natural extracts in mixture with wheat flour were used in various amounts for preparation of selected bakery products (wheat bread, sweet biscuits, salty crackers, and muffins). Specifically: turmeric (Curcuma longa, L.) rhizome extract (curcumin), quercetin dihydrate extracted from the pods of Sophora japonica, L., and extracts from medicinal fungus Shiitake (Lentinula edodes) and Maitake (Grifola frondosa) were used as additions. Antioxidant properties in total antioxidant activity (TAA; using DPPH radical scavenging assay), total polyphenols content and total phenolic acids content were examined, as well as the effect of selected natural extracts on the sensory properties of bakery products (intensity of certain characteristics and overall preference). The results of antioxidant properties varied according to the used extract and its amount. Compared with control products, the TAA was significantly higher in all enriched products. While the total polyphenol content was the highest in the bread and biscuits with quercetin (20.623 mg and 18.117 mg GAE.g^-1, respectively), the total phenolic acids content was the highest in those with curcumin (8.846 mg and 3.286 mg CAE.g^-1, respectively). The intensity of other smell and taste of enriched bakery products influenced considerably overall acceptance, e.g. the products with quercetin associated with bitter taste were evaluated as unfavourable. On the other hand, the breads and crackers with Shiitake extract with indistinct antioxidant properties were evaluated the best, followed with curcumin and Maitake extract. Considering our overall results, we can recommend chosen non-bakery raw materials for a production of new, innovative designed cereal-based products.

FLAVONOID AND ANTIOXIDANT ACTIVITY ANALYSIS OF ANTHOCYANIN BLACK RICE BRAN EXTRACT (ABRIBE) CV CEMPO IRENG ORIGIN FROM INDONESIA

Wiza Iswanti — 2024-09-16

Black rice is an indigenous food in Indonesia that is rich in anthocyanins, a group of plant pigments that are also found in berries. Despite the similarity in anthocyanin content, the high cost and limited availability of berries have restricted their use for extraction. Therefore, this study aimed to determine the total anthocyanin, flavonoid content, and antioxidant activity of black rice bran. To achieve this, the extraction was conducted with maceration using ethanol-citric acid and freeze-drying techniques. The process involved several stages, such as making black rice bran powder, maceration, homogenization, filtration, evaporation, and freeze-drying. The UV-Vis spectrophotometer was used to determine the total anthocyanin and flavonoid content, as well as antioxidant activity. The result showed a total anthocyanin content and the total flavonoid content of 2.48 ± 0.17 mg/gram and 3.76 ± 0.000 mg QE/g freeze-dried extract, respectively. Furthermore, the antioxidant activity of black rice bran CV Cempo Ireng extract and ascorbic acid as a standard was measured in terms of half maximal inhibitory concentration (IC₅₀) in the form of percentage inhibition (%I), with values of 112.42 ± 2.368 and 7.18 ± 0.042 μg/mL, respectively.

PROBIOTIC LACTIC ACID BACTERIA FROM ADUWA KO JAANR, A LESSER-KNOWN FERMENTED GINGER BEVERAGE FROM EASTERN HIMALAYAN REGION

Aawaj Rai — 2024-07-04

The Eastern Himalayan natives enjoy drinking Aduwa ko jaanr, a traditionally fermented mild-alcoholic ginger brew. Studies on manufacturing process and microbiological dynamics are infrequent for Aduwa ko jaanr. Current study analyzed the probiotic properties of Lactic Acid Bacteria (LAB) associated with Aduwa ko jaanr, using in-vitro method, simulating the conditions of intestinal tract. Three LAB isolates were screened and selected for preliminary characterization (morphological and biochemical). Isolates were identified as Lactiplantibacillus argentoratensis AKJ(W), Lactiplantibacillus argentoratensis AKJ(Y), and Levilactobacillus brevis AKJ(P) by 16S rRNA sequencing. Studies on growth kinetics of stationary phase and formation times of secondary metabolites with probiotic effects were conducted. Probiotic tests, namely acid-bile tolerance, phenol tolerance, cell surface hydrophobicity, auto-aggregation property, adherence to mammalian cell line, antibiotic susceptibility, antimicrobial activity and radical scavenging activity were performed. Results indicated the isolates to have health-benefiting properties with antibiotic resistance and inhibiting human pathogens. Isolates are predicted to survive in gut environment as they tolerated high bile salt concentration (0.5%), low pH (pH2) and high phenol concentration (0.6%). Results of cell surface hydrophobicity, auto-aggregation, and mammalian cell line (HEK 293) adherence tests suggested that isolates could adhere and possibly colonize intestine's inner wall. High radical scavenging activity of isolates suggested overall antioxidant property of the fermented beverage. MAR index showed isolates’ resistance to different antibiotics, indicating that their action is unaffected even when administered during illness. The present study suggests that LAB in Aduwa ko jaanr has potential probiotic properties which makes it an appropriate traditional beverage conferring health benefits.

EFFECT OF TOMATO POMACE ON SENSORY AND TEXTURAL PROPERTIES OF RAW-COOKED MEAT PRODUCT

Andrea Mesárošová — 2024-07-15

In the meat industry, there is a growing interest in the use of innovative processing methods, reformulated products, and the replacement of synthetic ingredients with natural bioactive compounds. Replacing synthetic antioxidants with natural antioxidants is a challenging process, but it can bring positive results. Our current research focuses on sensory and textural properties of raw-cooked meat product (frankfurters), which we observed on the 1^st, 7^th, 14^th and 21^st days of storage. We incorporated extract from tomato pomace into frankfurters as natural antioxidants. We used two concentrations of extract (3 mL.kg^-1 and 5 mL.kg^-1), the control with the addition of ascorbic acid and negative control. Sensory quality of meat product is one of the most important indicators that can influence the consumer. In the taste parameter, the best rated groups were Con-C and TCP-2. Furthermore, the addition of tomato pomace extract does not cause a significant change in the consistency of the meat products. After textural analysis, no statistically significant differences were observed between individual samples in any of the evaluated parameters.

COMPARISON OF THE CHEMICAL COMPOSITION AND MORPHOLOGICAL CHARACTERISTICS OF DIFFERENT CARROT VARIETIES

Vladimír Sitkey — 2024-07-08

Carrot (Daucus carota L.) is a globally significant root vegetable, rich in bioactive and nutritional compounds. Carrot is a crop with a wide range of phenotypic variability including colour, shape, size, and other characteristics. The aim of this work was to determine and compare selected morphological traits and chemical composition of 24 carrot varieties grown under open field conditions in Slovakia. Altogether, 11 qualitative characteristics and 6 quantitative parameters were evaluated. The carrot roots were also analysed for essential chemical constituents including reducing sugars (fructose, glucose, saccharose), carotenoids, dietary fibre, dry matter, ash, and mineral compounds. A wide range of diversity in morphological characteristics and chemical composition indicates a high variability of studied varieties. The root length ranged from 59 to 205 mm, root diameter varied from 17.7 to 39.0 mm and root weight ranged from 21.0 to 74.8 g. Based on the measurement results, saccharose was the dominant sugar ranging from 1.89 to 4.67 g.100 g^-1 of fresh weight, carotenoid content varied from 85.94 to 374.24 µg.g^-1 of fresh weight, the amount of dietary fibre ranged from 25.67 to 36.02% of dry matter. Considerable differences were also observed in the content of macro and microelements [mg.100 g^-1] ranging as follows: P (17.5 - 52.0), K (110.0 – 337.0), Na (65.9 – 186.0), Fe (0.324 – 3.340), Cu (0.042 – 0.126), Zn (0.152 – 0.945) and Mn (0.062 – 0.189). The presented results can provide useful information for carrot growers and consumers in terms of morphological characteristics as well as the chemical composition of individual carrot varieties.

MICROBIOLOGICAL QUALITY ASSESSMENT OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) MEAT TREATED WITH ROSEMARY AND THYME DRIED HERBS AND ESSENTIAL OILS

Ivana Timoracká — 2024-08-21

This study investigates the effects of thyme and rosemary dried herbs, as well as thyme and rosemary essential oils (1%, w/v), on the microbiological quality of vacuum-packed rainbow trout meat stored under refrigerated conditions (4 ± 1 °C) for 7 days. The microbiological quality of meat was monitored based on total viable counts, coliform bacteria, and lactic acid bacteria counts over a designated storage period (on the 0^th, 1^st, 3^rd, 5^th and 7^th day of storage). As expected, the highest total viable counts were observed on the 7^th day of storage in the untreated aerobically packed control group reaching 5.723 ± 0.021 CFU.g^-1. The tested treatments showed potential in reducing the growth of bacteria in rainbow trout meat samples. Across all bacterial groups under investigation, rosemary essential oil appears to have the most advantageous effect in inhibiting bacterial growth compared to other tested treatments. Cultivated isolates were identified by MALDI-TOF mass spectrometry and assigned to 33 species belonging to 14 families. The most prevalent family was Enterobacteriaceae (18.99%), and the most abundant species found in samples was Hafnia alvei (8.86%). Our findings suggest the potential of using thyme and rosemary in both essential oil and dried forms as natural preservatives to enhance the microbiological quality and longevity of refrigerated rainbow trout meat.

CHITOSAN: AN IN-DEPTH ANALYSIS OF ITS EXTRACTION, APPLICATIONS, CONSTRAINTS, AND FUTURE PROSPECTS

Shreya Hegde — 2024-07-12

The primary focus of this review is an eco-friendly biopolymer chitosan which is mainly produced by the conversion of environmental wastes into useful applications. Chitosan has drawn much interest due to its unusual characteristics, including anti-microbial, biodegradability, and non-toxicity. This study explores numerous approaches available for the production and extraction of chitosan from various sources, including crustaceans, fungi, and insects. The available techniques are classified into chemical and biological methods and further divided into enzymatic and fermentation methods. This review also covers the steps in the upstream and downstream processes that are involved in the production of chitosan. Additionally, a few techniques available for the characterization of chitosan are covered, including Fourier transform infrared spectroscopy, potentiometric titration, differential scanning calorimetry, thermogravimetric analysis, X-ray powder diffraction, and emission scanning electron microscopy. Comparisons are also made between the characteristics of chitosan derived from sources like insects and fungal strains. Characteristics of chitosan obtained from sources such as fungal strains and insects are compared with those of commercial chitosan. This study also focuses on the most recent applications of chitosan in the medical sector, wastewater treatment plant, agricultural sector, food packaging industry, and cosmetic industry. A few patents related to chitosan in the health sector are also discussed. Finally, it concludes that further research on chitosan and its derivatives is necessary to fully understand the advantages of this polymer. It also emphasizes the difficulties involved in extracting chitosan from crustaceans, insects, and fungi. To fully explore the advantages of this polymer, it is concluded that further research into chitosan and its derivatives is necessary.

ANTIMICROBIAL, ANTIOXIDANT, AND OPTIMAL CONDITION FOR EXOPOLYSACCHARIDES SECRATED FROM NEW LOCAL STRAIN-ISOLATE Bifidobacterium longum subsp. infantis strain Iraq-Basrah 3

Khulood Abdulkareem Hussein — 2024-08-14

Metabolic products of exopolysaccharide (EPS) generated by LAB strains have several biomedical effects. Our study focused on the isolation of a new strain of Bifidobacterium spp. From the sources of children's feces, examining them to choose the best EPS-producing strain, studying all the optimal conditions to increase the efficiency of producing more EPS, knowing the stage of their production, and finally introducing them into biomedical applications to test their antimicrobial and antioxidant activities. EPS is secreted by the most efficient new local strain Bifidobacterium longum subsp. infantis strain Iraq-Basrah 3 was extracted and purified, resulting in the highest production (2.08±0.41 g/L) in 1% (w/v) starch, which is the best carbon source with the best inoculum size of 1% (v/v) in 18 h at 37 °C and a pH value of 6.5. Coinciding with the best production phase, the generation time for the new strain was 32.2 min, and maximum production occurred after 16 h (2,45 g/L) to 20 h (2.14 g/L) between the end of the logarithmic phase and the early stationary phase. EPS exhibited antimicrobial activity, where S. aureus (17.24±1.2 mm) and E. coli (16.6±0.94 mm) were immediately resistant to EPS. In contrast, other pathogens were resistant to EPS, whereas strong antioxidant activity was observed at a concentration of 1500 µg/ml (84.43±0.95%). Through this study, we have proven that optimal conditions directly affect the quantity and production of EPS and that it has an inhibitory effect on some microbes in addition to being a natural antioxidant for DPPH free radicals.

STRUCTURE ELUCIDATION OF BIOACTIVE MATERIAL FROM STREPTOMYCES SPORORAVEUS AND ITS BIOLOGICAL ACTIVITY (PATHOGENIC MICROORGANISMS AND CYTOTOXICITY)

Dina Elghwas — 2024-07-12

Filamentous bacteria belonging to the Streptomyces genus are well known for their exceptional capacity to generate a diverse range of bioavailable secondary metabolites. In this work, an inoculum for fermentation was created using Streptomyces sp., which was isolated from Yanbu City, Saudi Arabia. It was 99% identical to Streptomyces spororaveus AD 4, according to 16S ribosomal RNA sequence homology studies. After using ethyl acetate to extract the fermented broth, the crude extract's purity was checked using high-performance liquid chromatography (HPLC). Following the purification stages, three pure bioactive fractions were isolated and given the names A, B, and C, with retention times of 2.251 ± 0.3 min, 4.342 ± 0.3 min, and 5.988 ± 0.3 min, respectively. Additionally, the spectroscopic examinations of these three compounds, including their GC-MS data, were used to determine their chemical structures by comparing them to published reference data. Additionally, the three fractions exhibit potent antimicrobial activity against Salmonella typhi ATCC 14028, Candida albicanc, Aspergillus niger, Klebsiella pneumoniae, Pseudomonas aeruginosa ATCC 9027, Staphylococcus epidermidis, Micrococcus luteus, E. coli ATCC 8739, and B. subtilis ATCC 6633. Also, the cytotoxicity of the bioactive fractions was assessed using the Hct-116 line. Of the three fractions, fraction C had the lowest cytotoxicity, with an IC50 value of 224.57 ± 5.82, followed by fraction B at 238.82 ± 2.57 and fraction A at 341.28 ± 1.69.

TWO-STEP CONTROLLED FERMENTATION USING NISIN Z-PRODUCING LACTOCOCCUS LACTIS SSP. LACTIS AND SELECTED STRAINS OF THE GENUS LACTIPLANTIBACILLUS SPP.

Franco Sosa — 2024-09-16

Spontaneous fermentation of Brassica vegetables is an ancient method that improves the foods' sensory properties, safety, and shelf life. However, in recent years, there has been a growing interest in studying controlled fermentation with lactic acid bacteria selected based on their technological properties. This study reported the inhibitory activity of a Lactococcus lactis ssp. lactis of marine origin and the evolution of a two-step controlled fermentation using the cited strain and two selected Lactiplantibacillus strains. Lc. lactis ssp. lactis was studied by phenotypic and genotypic methods. The inhibitory activity was assayed against common contaminants and pathogens. The strain behaviour in Chinese cabbage and white cabbage fermentation was studied by monitoring the cell count and inhibitory activity against Listeria innocua ATCC 33090. The two-step controlled fermentation of Chinese and white cabbage was conducted using, in the first step, the Lactococcus strain and, in the second step, the two Lactiplantibacillus strains. The evolution of the processes was monitored by cell counts and pH measurements. PCR amplification confirmed the presence of nisin Z gen in the Lc. lactis ssp. lactis strain. The bacteriocin exerted inhibitory activity against Gram-positive related species but not against Gram-negative ones. The results obtained in the controlled fermentation suggested that the combination of the selected strains is compatible and may improve the fermented matrices' safety.

SCREENING FLAX FOR IDENTIFYING CADMIUM TOLERANT CULTIVARS FOR GROWTH IN POLLUTED ENVIRONMENT

Simona Ilavská — 2024-09-18

Toxic metal pollutants such as cadmium disrupt all stages of plant development. Flax (Linum usitatissimum L.) has demonstrated the ability to tolerate and accumulate high amounts of cadmium, making it suitable for phytoremediation. Within-species variability of cadmium tolerance and uptake needs to be examined in controled conditions to assess multiple beneficial, or even required traits for use in phytoremediation programs. In this study, 31 flax cultivars were screened for their ability to germinate and grow in the presence of a sublethal concentration of cadmium (20 mg.kg^-1). Several parameters, including growth indicators and photosynthesis performance, were analyzed using principal component analysis. A subset of flax cultivars was then selected for measuring cadmium uptake using gamma spectrometry. The results showed that the cultivars Belinka, Diana, Laura, Marina, Flanders, and Jitka have comparable metal uptake and transfer to shoots. Among these, the cultivar Jitka proved to be the best candidate for phytoremediation, consistent with previous reports.

SYNERGISTIC EFFECTS OF NEEM OIL AND GENTAMICIN ON PSEUDOMONAS AERUGINOSA VIA PHZM GENE DOWNREGULATION: A COMPREHENSIVE REVIEW

Mais Emad — 2024-07-08

Exploring the antibacterial potential of neem oil (Azadirachta indica) in combination with gentamicin (GEN) against pathogenic molds, especially Pseudomonas aeruginosa, has drawn concern due to the quest for natural treatment options against incurable diseases. Prospective research directions include looking for natural cures for many of the currently incurable diseases available now.

microbial identification system, were used to identify the isolates. The research utilized a range of methods, such as the diffusion agar well (AWD) assays, TEM (transmission electron microscopy) analysis, minimum inhibitory concentration (MIC) assays, and real-time PCR (RT-qPCR) to analyze bacterial expression and the antibacterial action of neem oil (Azadirachta indica) combined with gentamicin (GEN) against the pathogenic bacteria Pseudomonas aeruginosa between others.

The combined effects of neem oil and GEN on P. aeruginosa are extensively investigated in this study, with particular attention paid to the downregulation of the virulent factor gene phzM, inhibition of biofilm formation, morphological changes, and gene expression, in that proportion. Results show that neem oil has strong antibacterial activity against P. aeruginosa and S. aureus, preventing the formation of biofilms and causing morphological alterations. In addition, the synergistic effects of neem oil and GEN are demonstrated, together in order with the downregulation of the phzM gene in P. aeruginosa. These results highlight the increased effectiveness of neem oil when combined with GEN and point to the potential of the oil as a stand-alone antibacterial agent. They also highlight the need for more study to overcome antibiotic resistance in harmful bacteria. Overall, our results point to a possibility that neem oil extract, either alone or in combination with GEN, can suppress the development of pathogenic microbes. This synergistic impact is related to the downregulation of a virulence factor gene. To address the drug resistance linked to pathogenic microbes, greater study is required. Novelty of study addresses the important issue of antibiotic resistance by exploring the potential synergistic effects of neem oil and gentamicin on pathogenic bacteria, particularly Pseudomonas aeruginosa. This topic is highly relevant in the context of the global challenge of antimicrobial resistance.Novelty and relevanc the important issue of antibiotic resistance by exploring the potential synergistic effects of neem oil and gentamicin on pathogenic bacteria, particularly Pseudomonas aeruginosa. This topic is highly relevant in the context of the global challenge of antimicrobial resistance.

SHEDDING LIGHT ON GENETIC RELATIONSHIPS, PLASMID PROFILES AND ANTIBIOTIC RESISTANCE PATTERNS OF CLINICAL ESCHERICHIA COLI STRAINS: PULSED-FIELD GEL ELECTROPHORESIS PERSPECTIVE

Ahmet Uysal — 2024-08-14

In the present work, 47 Escherichia coli isolates collected from various clinical samples were elucidated with regard to genetic relationship, antibiotic resistance and plasmid profile. The genetic diversity of the isolates was defined by the pulsed field gel electrophoresis (PFGE) method. With a degree of similarity of 80%, the results from PFGE separated the E. coli strains into 39 different groups representing four subtypes. Antibiotic resistance patterns and extended spectrum of beta lactamase (ESBL) producing properties of the strains were determined by using a disk diffusion and double disc synergy method, respectively. According to the susceptibility test results, 36 distinct resistance profiles (resisto type) were observed among clinical strains. The strains were mostly resistant to ampicillin (100%) and this has been followed by cephalothin and ticarcillin/clavulanic acid with the ratio of 89.36%, cefuroxime with the ratio of 87.24%, tetracycline and cefotaxime with the ratio of 80.85%. It was observed that 24 of the strains (51.06%) were defined as ESBL positive. When E. coli strains were evaluated according to plasmid size, it was determined that 27 of 47 strains (57.44%) carried plasmids and the sizes of the determined plasmids were ranging between 77.1 kb and 1.6 kb. It was concluded that plasmids of E. coli strains are randomly distributed and no significant correlation was found between antibiotic resistance patterns and plasmids.

MOLECULAR CHARACTERIZATION AND PATHOGENICITY TEST ON CITRUS FRUITS BY GREEN MOLD AND BLUE MOLD

Md. Mamun Sarker — 2024-09-18

Citrus fruits are essential for preventing various health conditions, including diabetes, neurological diseases, and cancer. Among the postharvest diseases affecting citrus fruits, Penicillium digitatum and Penicillium italicum are particularly significant. This study aimed to characterize Penicillium spp. isolated from three citrus varieties: orange (Citrus sinensis), small orange, and Malta. Pathogenicity tests confirmed that these Penicillium isolates were capable of infecting the tested citrus fruits. For molecular characterization, PCR amplification of the D1/D2 domain of 26S rDNA was performed using universal primers, which target the conserved regions of the nucleotide sequence. The PCR products were inserted into the pGEM-T Easy vector and transformed into E. coli Dh5α. The presence of the D1/D2 domain was verified by endonuclease digestion with EcoR1. Sequencing was conducted using the T7 promoter primer, and the resulting DNA sequences were analyzed with the DNAMAN analysis system. Sequence analysis revealed that the D1/D2 region of 26S rDNA from the orange isolate showed 99% similarity with Penicillium sp., while the D1/D2 region from the small orange isolate had 99.84% similarity with P. digitatum strain CBS 112082. The D1/D2 region from the Malta isolate showed 100% similarity with P. digitatum. Multiple sequence alignments among the three Penicillium isolates revealed a 98.81% identity. This study highlights the use of molecular techniques for understanding the pathogenicity of Penicillium spp. in citrus fruits.

ENTEROBACTER CLOACAE LIPOPOLYSACCHARIDE EXPORT SYSTEM PROTEIN (LPTC) GENE EXPRESSION VARIATION VIA EXPOSE TO BIOSYNTHESIZED ZINC OXIDE NANOPARTICLES

Nadhim Mushtaq Hashim Al-Bderee — 2024-07-08

Synthetic nanoparticles (NPs) have become more widely used in the disinfection and health sectors owing to their ability to effectively penetrate biological systems. Recent research has demonstrated the ability of microbial proteins and enzymes to function as reducing agents throughout the NP-production process, providing a different option to chemical and physical techniques. This method not only saves money and is effective, but also has the least possible environmental impact. This work used Lactobacillus spp., as the reducing and capping agent to create zinc oxide nanoparticles, (ZnO NPs). Numerous analytical techniques were employed to examine the generated ZnO NPs; these techniques include ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). As an opportunistic pathogenic bacterium, Enterobacter cloaca possesses several virulence characteristics that enable it to infiltrate target tissues. However, bacteria can become resistant to antibiotics, which in turn makes treating bacterial infections becomes more difficult. With the development of science at the biotechnology level, using zinc oxide ZnO NPs on isolates of Enterobacter cloacae, we conducted research in the promising field of nanotechnology. The impact of three different concentrations of ZnO NPs on the gene expression of Enterobacter cloaca lipopolysaccharide transport (Lpt) proteins in isolates obtained from some patients suffering of various infections was investigated. Bacteria with the highest multidrug resistance were selected for further analysis. Expression of LptC gene was reduced significantly at concentration of 125 mg/mL (P < 0.01) for all the isolate that treated with ZnO NPs.

The IMPACT OF HONEYBEE GUT BACTERIA ON THE SURVIVAL OF HONEYBEES EXPOSED TO INSECTICIDES

Abdulaziz A. Al-Humayd — 2024-09-30

The widespread use of insecticides poses a significant threat to the health and sustainability of honeybees (Apis mellifera). This study aimed to isolate, identify, and investigate the potential of honeybee gut bacterial strains in mitigating the detrimental effects of insecticides on honeybees and extending their lifespan. The efficacy of seven honeybee gut bacterial strains in reducing insecticide toxicity was evaluated. Through the identification of honeybee gut bacterial isolates using 16s rRNA, seven strains were identified, namely Priestia endophytica, Bacillus subtilis, Bacillus pumilus, Peribacillus frigoritolerans, B. subtilis, Bacillus pumilus, and Bacillus tequilensis. The experimental results revealed that bees treated with these gut bacteria significantly reduced oxidative stress markers and detoxification enzyme levels compared to untreated bees. Moreover, the treated bees demonstrated enhanced immune responses. The bees treated with deltamethrin + intestinal bacteria showed an increase in bees' lifespan to 6.33 days compared to a lifespan of 4 days with deltamethrin only. Similarly, bees treated with acetamiprid intestinal bacteria had further extended to 10.33 days compared to a lifespan of 7.67 days with acetamiprid. These findings suggest that using honeybee gut bacterial strains may serve as a sustainable strategy to mitigate the harmful impacts of insecticides on honeybees, thereby promoting their overall health and contributing to the preservation of pollination services and apiculture. Further research is warranted to elucidate the underlying mechanisms and optimize the application of these natural products in honeybee management practices.

IN VITRO AND IN VIVO INVESTIGATION OF PROBIOTICS ISOLATED FROM HUMAN MILK

Manikandan Kathirvel — 2024-09-16

People all over the world are embracing probiotics as a result of growing awareness of the health advantages connected to ingesting living bacteria. Proper administration of probiotics has been shown to provide numerous health advantages to the host. The Lactobacillus genus, which naturally resides in the mucosal linings of humans and animals, and it is essential for stabilizing the gastrointestinal tract and protecting intestinal health from infections. There has been a great deal of interest in their potential uses as probiotics, mucosal vaccine vectors, and agents regulating metabolic activities. The present study aimed at isolating and characterizing novel probiotics from human milk and functionally assessing them in vivo for their physiological, enzymatic and antimicrobial activity. Probiotic isolates from human milk were amylolytic, proteolytic and lipolytic and were found to be tolerant to low pH of 3.5, 10% salt and 0.3% bile salt. Primary method of cross streaking and secondary streaking by agar diffusion method revealed antagonistic activity of the isolates against tests pathogens of humans viz., S. aureus Newman, P. fluorescens, S. epidermis and S. aureus. Antibiofilm activity of probiotic isolates in vivo against P. fluorescens and S. aureus Newman indicated that the metabolites present in the Cell Free Supernatant (CFS) of the isolates may have the ability to inhibit the formation of biofilm of pathogenic strains. The most efficient probiotic isolates was identified as Weissella confusa and the NCBI GenBank accession number was obtained. The infected mice administered with probiotic isolate Weissella confusa PS17 showed reduced mortality rate than the mice infected with pathogenic strain S. aureus Newman, thus indicating that probiotic strain boosted the immune response of the mice. The Serum uric acid levels was normalised after the infected mice was treated with W. confusa PS17 and this in turn enhanced the survival rate of mice. The present study indicates that isolate W. confusa PS17 can be a promising candidate in improving the condition of health.

IN-SILICOIDENTIFICATION OF FLAVONOIDS BASED INHIBITORS AGAINST SORTASE-A FROM ENTEROCOCCUS FAECALIS (Ef)

SURAJ SINGH — 2024-09-19

The enzyme known as SortaseA(SrtA) is widespread present in gram-positive bacteria. SrtA is responsible for anchoring a large number of surface protein virulence factors to the cell wall. This enzyme is not involved in bacterial growth and is also present on the cell membrane, which makes it more accessible for the design of inhibitors. In the case of Enterococcus faecalis (Ef), which is responsible for a wide range of nosocomial infections, SrtA from this organism promotes development of biofilm, which in turn makes bacteria resistant to antibiotics. Numerous inhibitors have been identified and characterized against Ef-SrtA; however, none have been clinically approved till now. Natural compounds and their derivatives showed inhibition against Ef-SrtA. In this work, a flavanoids-based in-house natural library was screened against Ef-SrtA to see how these molecules bind to active site of Ef-SrtA. Furthermore, the absorption, distribution, metabolism and excretion (ADME) properties of the top five compounds, Abyssinones lii, Apigenin, Rutin, Fisetin and Kaemferol, were calculated, Additionally, the correlation between the structure and function of these top five compounds was analyzed using Density Functional Theory (DFT) studies.

ANTIFUNGAL ACTIVITY OF TWO STREPTOMYCES SPECIES ISOLATED FROM EGYPTIAN SOIL AGAINST SOME PHYTOPATHOGENIC FUNGI

Amira A. El-Fallal — 2024-07-04

The objective of this study was to isolate and identify Streptomyces species with high antifungal activities against some phytopathogenic fungal strains. Fourteen different Streptomyces isolates were isolated from the soils of the Damietta Governorate, Egypt. The results indicated that two isolates (O5 and M7) showed potent antifungal actions against the tested fungal strains including Alternaria alternata, Macrophomina phaseolina, Fusarium oxysporum, Penicillium italicum, Rhizoctonia solani and Trichoderma harzianum. The strongest inhibition zones of the isolates O5 and M7 were obtained against A. alternata (3.5±0.04 cm and 3.63±0.02 cm, respectively) and M. phaseolina (3.23±0.03 cm and 3.43±0.01 cm, respectively). The two isolates were identified classically and using 16S rDNA sequencing as Streptomyces flavovirens (accession number: EGDA-O5 OM301640) and S. gougerotii (accession number: EGDA-M7 OM301639). The obtained results confirmed that S. flavovirens and S. gougerotii might be used as promising antifungal agents against various fungal strains.

IDENTIFICATION OF ANTIBACTERIAL AGENTS AGAINST KLEBSIELLA PNEUMONIAE TARGETING THE CTX-M-15 PROTEIN USING INTEGRATED STRUCTURE MODEL-BASED VIRTUAL SCREENING METHODS

Saleh M. Al-Maaqar — 2024-10-01

The spread of carbapenem-resistant Gram-negative bacteria, particularly those having the bla _CTX-M-15 gene, has stimulated a global challenge for β-lactam antimicrobial effectiveness. This study aims to identify commercially available compounds that demonstrate strong antibacterial properties with high efficacy and low toxicity to combat the increasing problem of antibiotic resistance. Virtual screening and molecular docking techniques were employed to generate a pharmacophore model based on the molecular structure. Eleven potential compounds were selected based on their IC₅₀values. Subsequently, a molecular docking approach was employed to select the best three small molecules for further comprehensive investigation. Moreover, absorption, distribution, metabolism, and excretion (ADME) and toxicity analysis ensured that it can be used as a drug without the effect of health. Finally, molecular dynamic (MD) simulations and generalized Born model and solvent accessibility (MMGB/SA) were carried out to evaluate the stability of these compounds against the receptor. Three selected compounds, specifically ZINCCID (ZINC94211493, ZINC20528448, and ZINC04331046), have exhibited strong binding affinities of -8.4, -8.1, and -7.7 kcal/mol, respectively. This has been predicted as a potential competitive inhibitor targeting CTX-M-15. However, further assessment through experimental lab studies is required to evaluate the efficacy of these compounds. Initially, a structure-based model was constructed, and subsequently, molecular docking, MD simulation, ADMET analysis, and MMGB/SA were performed. Through the A-to-Z virtual screening process, the top three natural compounds were identified as potential lead molecules in the development of novel drugs targeting CTX-M-15 for combating Klebsiella infections.

Keywords: Klebsiella; Structure-based; Molecular docking; Pharmacophore modeling; CTX-M-15 protein; ADMET; MMGB/SA, MD simulation.

ENHANCING ELECTRICITY GENERATION USING FUNGAL LACCASE-BASED MICROBIAL FUEL CELL

Hani Moubasher — 2024-07-10

Microbial fuel cells (MFCs) are very important source to obtain green electricity and also for decontamination of waste water. Bioelectricity yield from biofuel cells is still needed for maximizing. Microbial laccases, especially those produced by fungi, are currently considered to be one of the most promising biocatalyst for bioelectricity production and also purification of water from the different pollutant, especially phenolic compounds. In the present work, different electrolyte solutions used in anode and cathode chambers to evaluate efficiency of each to produce voltage & current and also to prove that using economical electrolytes, which were agro-industrial waste called el-ghasheem at anode and only tap water at cathode, achieve good results in comparison with other commonly used electrolytes which were glucose, sodium nitrate, mono-potassium phosphate, di-potassium phosphate, ammonium chloride and magnesium sulfate. The use of El-ghasheem in the economic MFC showed power improvement results when fungal laccase, produced from Monodictys castaneae fungus, had been used as cathodic reaction catalyst to increase voltage production from 0.466±0.003 V to 0.807±0.002 V and current from 0.025±0.003 A to 0.09±0.003 A at 37 °C, anolyte pH 6 and catholyte pH 5 for 10 days incubation period. It was noticed that this laccase enzyme had the 98.38±0.264 % phenol removal activity from anode chamber through indirect effect and 99.69±0.276 % phenol removal activity from cathode chamber through direct effect when El-ghasheem was used as the organic fuel at the anode side. In this study using unstudied agro-industrial waste, Electricity was produced by the new fungal laccase which showed the high performance in electricity production enhancement and also phenol compounds removal through low cost MFC.

PLANT-GROWTH-PROMOTING AND ANTIFUNGAL ASSET OF INDIGENOUS DROUGHT-TOLERANT RHIZOBACTERIA ISOLATED FROM OLIVE (Olea europaea L.) RHIZOSPHERE

Mohammed Ajdig — 2024-07-02

Faced with global environmental challenges, the quest for sustainable food production has gathered momentum. While abiotic stresses adversely affect plant health and productivity, Verticillium wilt causes considerable yield losses worldwide, particularly in crops such as olive. Recently, drought-tolerant bacteria have been used to alleviate both abiotic stress and pathogen pressure in crops. In this context, our work focuses on the isolation of tolerant indigenous rhizobacteria to mitigate these challenges by investigating their role in biocontrol and abiotic stress tolerance. Thus, a total of 94 rhizobacterial strains were isolated from the rhizospheres of olive trees in southeastern Morocco and characterized to identify tolerant plant growth-promoting rhizobacteria that inhibit Verticillium dahliae. 24 strains demonstrated in vitro suppression of Verticillium dahliae Klebahn, and exhibited tolerance to different abiotic stresses (drought, salinity, and high temperature). In addition, they proved xerotolerant (Aw ≤ 0.91), halotolerant (≥10% NaCl), and thermotolerant (≥ 55°C) capabilities. Beyond, these isolates showcased multifaceted plant growth-promoting traits, such as phosphate solubilization and significant synthesis of essential bioactive compounds like siderophores, indole-3-acetic acid and hydrolytic enzymes. Evaluating outcomes, three standout rhizobacterial isolates emerged due to their exceptional stress tolerance, unique plant growth-promoting qualities, and potent antagonistic potential. Molecular analysis identified them as Bacillus paranthracis (OZ-60) and Bacillus licheniformis (OZ-48 and OZ-77) through 16S rRNA sequencing. Besides enhancing plant abiotic stress resistance, these isolates hold promise in bolstering the sustainability of olive cultivation and fortifying plant defenses against pathogens.

DECIPHERING THE OILSEED BACTERIAL ENDOPHYTES AND STUDY OF THEIR ROLE AND TRIPARTITE INTERACTIONS WITH PLANTS AND PATHOGEN

Tamali Sinha — 2024-07-03

Endophytes colonize interior regions of oilseeds depending on water, nutrient, space availability and microbial competition. Oilseeds are filled with oil globules making it difficult for microbes to obtain direct uptake of water and nutrient for growing into colonies. Recent research shows very less areas explored in endophytic study in oilseeds and as endophytes play a vital part in managing diseases in plants by releasing genes encoding jasmonate and salicylic acid which induces defense against pathogens and modify plant regions structurally adding to their fitness and increased productivity, their study is indispensable. This review focuses on the bacterial endophytes in oilseeds, the challenges faced in their isolation, their colonization and interactions with host and pathogens and their applications. Oilseed endophytic study is essential for understanding the benefits of oilseeds consumed as vegetable oil or used as fuel by people all over the world.