ISOLATION AND CHARACTERIZATION OF THE PROBIOTIC POTENTIAL OF LACTIC ACID BACTERIA AND THEIR APPLICATION IN BIOFILM ERADICATION OF PSEUDOMONAS AERUGINOSA PA01

Abstract

Probiotic microorganisms were isolated from fermented curd, idli batter, lentils, human milk, and healthy infants’ faecal matter. A total of 27 isolates were screened for acid and bile tolerance, with 12 isolates showing resistance to low pH and bile and nine isolates indicating significant viability during gastro-intestinal simulation. They were further investigated for probiotic properties where isolate B33 (from idli batter) with 66.57 ± 0.05% autoaggregation potential, isolate D25 (from curd) with 93.25 ± 0.60% hydrophobicity, and 75.25 ± 0.21% biofilm-forming potential were observed as significant isolates. Some isolates have shown positive lipolytic, amylolytic, and proteolytic activity and all the isolates have shown negative hemolytic and gelatinase activity. Antibiotic resistance was also analysed using the disc diffusion method, wherein isolates B11, B32, and B34 were most resistant to eight antibiotics. The antibacterial properties of cell-free supernatant (CFS) of isolates were determined against Pseudomonas aeruginosa PA01, Bacillus cereus, Staphylococcus aureus, and Salmonella Typhimurium by agar well diffusion method, wherein isolates B11, B32, D25, and B34 showed high antibacterial activity. Potential probiotic isolates D25 and B11 were identified using the 16S rRNA sequencing method, and they were identified as Lactiplantibacillus plantarum and Pediococcus pentosaceus, respectively. Application of their CFS (20 µL) for biofilm eradication was also studied on the biofilm of Pseudomonas aeruginosa PA01 by 96-well microtiter plate assay, where isolate D25 showed 65 ± 0.20% biofilm eradication. The study suggested that both isolates were potential probiotics and could be applied in food preparation, animal feed, or the pharmaceutical industry.