Sustainable lipase production from an unexplored marine Bacillus safensis strain using waste cooking oil

Abstract

Lipases are versatile enzymes with applications in diverse sectors, including detergents, pharmaceuticals, food, and biodiesel production. Marine microorganisms are adapted to extreme and saline habitats and can produce robust enzymes with unique catalytic properties. This study aimed to isolate and screen potential lipase-producing bacteria and optimise fermentation conditions for enhanced production of selected bacterial isolates. The bacteria were isolated on Zobell marine agar using the standard spread plate method. Primary screening involved the tributyrin agar plate method, and secondary screening used the rhodamine olive oil agar plate method, followed by quantitative screening in a lipase-production medium supplemented with waste cooking oil (WCO). Based on the screening results, isolate AS15 was selected for further characterisation through morphological, biochemical, and 16S rRNA gene sequencing. Lipase production was optimised using the one-factor-at-a-time (OFAT) method, evaluating the effect of different media compositions, salt concentration, WCO concentration, pH, inoculum age, and inoculum size. The optimisation resulted in around an 11.7-fold increase in the lipase production from isolate AS15 in a production medium containing WCO. The isolate was identified as Bacillus safensis based on the Biolog Microbial identification system and 16S rRNA gene sequencing. To our knowledge, this is the first report on lipase production from the marine Bacillus safensis strain. This research underscores the potential of the marine environment as a rich source of lipase-producing bacteria with implications for biotechnological applications. Further characterisation of these isolates could offer valuable insights into their enzymatic properties and industrial potential. • Waste cooking oil (WCO) was used as a carbon source for sustainable lipase production • Potent lipase-producing Bacillus safensis was isolated from marine sediment • The substrate utilisation profile revealed diverse metabolic capabilities • One-factor-at-a-time optimisation resulted in an 11.7-fold increase in lipase production • First report on lipase production from slightly halophilic marine Bacillus safensis sp.

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