Optimization of lipase production by response surface methodology from Serratia marcescens VT 1 isolated from oil contaminated soil

The current manuscript focuses on the isolation of a potent lipase-producing mesophilic bacteria and explores the optimization of culture parameters to enhance lipase production. From a total of 83 bacterial isolates, after screening on tributyrin agar plate, rhodamine olive oil agar plate, and submerged fermentation studies, the isolate VT 1 with a lipase activity of 23.85 U/mL was selected. The potent isolate VT 1 was identified as Serratia marcescens (accession number OM757842) based on 16S rRNA gene sequencing and standard morphological and biochemical procedures. The lipase production was optimized by a statistical approach using response surface methodology after identifying the significant factors with Plackett-Burman design using Design-Expert, version 11 software. Nutrient factors- peptone, yeast extract, sodium chloride, and olive oil- were identified as the significant factors. Its optimization via central composite design of response surface methodology with Design-Expert, version 11 (olive oil: 50 mL/L, sodium chloride: 8.87 g/L, peptone: 8.15 g/L, yeast extract: 10 g/L) resulted in an enhanced experimental lipase activity of 55.95 U/mL in comparison to the predicted lipase activity of 56.858 U/mL. The study brought forth the isolation of a lipase-producing Serratia marcescens strain VT 1 and highlighted the importance of optimizing culture parameters for augmented production of lipase. The optimization via response surface methodology resulted in a 2.34-fold increase in lipase production.