APPLYING AN ORTHOGONAL ARRAY TAGUCHI DESIGN FOR CHITINASE OPTIMIZATION BY Trichoderma longibrachiatum MW433820 AND ITS EFFICACY IN GREEN BIOCONTROL FOR SUSTAINABLE AGRICULTURE

Abstract

Increasing efforts are aimed at utilizing rhizospheric saprophytic fungi as biological control agents against phytopathogens to improve crop production. In this study, an unconventional fungal isolate "genetically identified as Trichoderma longibrachiatum" and given the GenBank accession no. MW433820, has shown the potential to produce chitinase enzyme, using liquid and solid wastes from the olive oil-processing industry. Olive mill solid waste and olive mill waste water demonstrated high nutritional value and strong physical support for fungal growth and enzyme production. Value of 417.60 U/ml was the highest chitinase activity achieved after 7 days of submerged cultivation in both solid and liquid olive wastes without any additives. The orthogonal array Taguchi design used for further optimization of  the production process. The highest significant optimization of chitinase production (3184.69 U/ml), with ~7.63-fold increase was obtained by supplementation of basal medium with the organic nitrogen source (soy bean), NaCl and K₂HPO₄. The high antagonistic activity of Trichoderma longibrachiatum was observed against the soil-borne pathogens Fusarium oxysporum and Fusarium solani, depending on fungal parasitism, by coiling around the pathogens and producing the cell wall-degrading enzyme chitinase. From the obtained results, we can deduce, the potential application of Trichoderma longibrachiatum as a biocontrol agent with no harm to the host plant.