ISOLATION, MOLECULAR IDENTIFICATION, AND ASSESSMENT OF THE BIOTECHNOLOGICAL POTENTIAL OF A NOVEL LIPASE-PRODUCING ASPERGILLUS FLAVUS ISOLATE FROM RIJAL ALMAA, SAUDI ARABIA

Abstract

Background:  The increasing depletion of fossil fuels has created a global demand for renewable and environmentally friendly alternative energy sources. The outcomes of this study are expected to contribute to the development of a cost-effective, locally sourced lipase preparation with potential applications in detergent, food, and biofuel industries. Methods:  A lipase-producing fungal isolate was obtained from Rijal Almaa, Saudi Arabia. Lipase activity was screened using Tween 80 agar, Tributyrin agar, and Phenol Red agar media. Molecular identification was performed through 18S rDNA sequencing, identifying the isolate as Aspergillus flavus (MH279408.1). Lipase production was optimized by varying carbon, nitrogen, mineral sources, and pH conditions. The culture medium was inoculated with fungal spores and incubated at 30 ± 1°C for 5 days. Enzyme activity was determined using p-nitrophenyl laurate (p NPL). The enzyme was partially purified by ammonium sulfate precipitation and characterized biochemically. Results:  The isolate exhibited strong lipolytic activity on all screening media. partially Purified lipase showed a molecular weight of 44 kDa on SDS-PAGE analysis. The enzyme demonstrated optimal activity at 20°C and pH 5, with kinetic parameters of Km = 0.4 mM and Vmax = 3.125 μmol/min/mg. Lipase activity was enhanced by Hg²⁺ and inhibited by Cu²⁺, Fe³⁺, and EDTA. Aspergillus flavus (MH279408.1) showed significantly high lipase production under optimized conditions. Conclusion:  The obtained results demonstrate the biotechnological potential of Aspergillus flavus lipase for biodiesel production and enzymatic bioremediation of lipid-rich wastewater. The study also highlights the importance of optimizing physicochemical parameters, particularly pH, for improving lipase efficiency in industrial and environmental applications.