Optimization of culture conditions for enhanced lipase production by an indigenous Bacillus aryabhattai SE3-PB using response surface methodology

Abstract

Lipases are enzymes that hydrolyze fats into fatty acids and glycerol at the water–lipid interface and are also involved in a variety of bioconversion reactions in non-aqueous and micro-aqueous environments. In this study, we optimized the culture conditions for extracellular lipase production by an indigenous lipase-producing bacterial strain isolated from lipid-rich wastewater, using response surface methodology. The studied isolate was identified as Bacillus aryabhattai SE3-PB by polymerase chain reaction and analysis of 16S rDNA. Sunflower oil was found to induce maximum lipase production. Face centered central composite design revealed that temperature (40 °C), pH (7.6), inoculum volume (2.8%, v/v), agitation (193 rpm) and inducer oil concentration (2%, v/v) significantly influenced lipase production at the respective optimum conditions. The coincidence of observed lipase production (264.02 ± 1.94 U/mL) with predicted lipase yield (265.82 U/mL) coupled with a high correlation coefficient (R2 = 0.9919, P < 0.01) confirmed the validity of the model. A 7.2-fold increase in lipase production was obtained in the optimized medium compared to the basal medium. These findings provide the first report on lipase production and optimization by B. aryabhattai SE3-PB and suggest a rational choice of optimum processing conditions for commercial lipase production by B. aryabhattai SE3-PB.

Keywords

• Lipase
• Bacillus aryabhattai SE3-PB
• lipid-rich wastewater
• face centered central composite design
• response surface methodology