Isolation and selection of lipase-producing fungi based on lipase activity and hydrolytic potential on soybean oil and grease trap scum

ABSTRACT:

The use of fungal biomass as a lipase biocatalyst represents an attractive approach for the treatment of oil wastewater and production of biodiesel from oil and residual grease, due to its greater stability, possibility of reuse, and lower cost. In this work, a hundred filamentous fungi were isolated from grease trap and sewage scums, soil, and necrotized plants and insects tissues. The isolates were assessed for growth and lipase activity in the culture basic medium, for extracellular lipase activity, and mineral medium minimum + soybean oil + rhodamine, for intracellular lipase activity, with positive and differential response of 66 of them, including those belonging to the genera Aspergillus , Beauveria , Botrytis , Cladosporium , Colletotrichum , Fusarium , Geotrichum , Penicillium , Rhizomucor , and Verticillium . Following, previously selected Penicillium sp F002 and Rhizomucor sp. F018 isolates were evaluated in solid-state fermentation, for the hydrolytic potential on edible soybean oil and grease trap scum, quantified by: CO₂ production_, removal of the content of oils and greases, and biomass growth. Results confirmed the high extracellular lipase-activity of Penicillium sp. F002 and the high intracellular lipase activity of Rhizomucor sp. F018. Therefore, the isolated Rhizomucor sp. ECG18 showed potential for use in future research, in the form of whole-cell lipases, for oily wastewater treatment, and as a biocatalyst in the production of biodiesel from oil residues.

Keywords:
isolation and selection; fungi; lipase activity; hydrolysis; soybean oil; grease trap scum