Optimization of extracellular lipase production by Debaryomyces hansenii isolates from dry-salted olives using response surface methodology

Abstract

The lipase production by Debaryomyces hansenii strains isolated from dry-salted olives cv. Thassos was investigated. Glucose, olive oil and pH were essential to obtain a high lipase yield. Optimization of the medium components which enhance lipase production by the strain D. hansenii YLL29 was achieved with the aid of response surface methodology. The composition of the optimized medium to enhance lipase production by D. hansenii is as follows (g/L): yeast extract 5.0, peptone 10, K2HPO4 4.0, MgSO4·7H2O 1.0, glucose 13.1, olive oil 19, Tween 80 3.8, and pH 6.4. Practical validation of the optimum medium gave lipase activity 7.44U/mL, which was 2.28-fold higher than the unoptimized conditions. Under the optimized conditions the twenty D. hansenii isolates showed increased lipase activity fluctuating between 6.00 and 7.44U/mL. The results corroborated the validity and the effectiveness of the model, as the statistical approaches proved to be suitable in predicting the optimum production medium composition for maximum extracellular lipase yield. The high lipolytic activity of D. hansenii YLL29 (7.44U/mL) indicates the possible commercial importance of this isolate.