Publication

Abstract : One of the major concerns of reusing the wastewater for irrigation or agriculture is the health risks associated with the nematode eggs. Inadequate usage of toxic chemicals as nematicides has urged us to develop an environmentally safe alternative. The predatory nematophagous fungi have been widely used in control of nematode as an alternative strategy. Extracellular enzymes like chitinases, lipases, and proteases from fungi appeared to be a promising candidate that can damage the main structural components in the nematode eggshell and cuticle. This study aimed to evaluate the nematicidal potential of two biocontrol fungi Aspergillus niger and Penicillium oxalicum against Caenorhabditis elegans as the nematode model. The fungi were grown at different point of time in a minimal production media supplemented with olive oil, casein, and colloidal chitin to induce the production of lipase, protease and chitinase enzyme respectively. Enzyme activity and specific activity were quantified and compared. All the crude enzyme samples with the highest activity were used to treat the eggs and larvae of C. elegans and the rate of hatch inhibition and mortality was determined. Best effect (100% mortality) was obtained with oil and casein enriched media extract of P. oxalicum whereas Aspergillus niger extract had the best inhibition of egg hatching with oil (82%) and protein (72%) enriched media extract. Hence cultivation of the selected fungi by enrichment with the specific substrate (protein/oil) might potentially be used to reduce the nematode load in wastewater or compost.