RESPONSE SURFACE METHODOLOGICAL APPROACH TO OPTIMIZE THE NUTRITIONAL PARAMETERS FOR ENHANCED PRODUCTION OF LIPOPEPTIDE BIOSURFACTANT IN SUBMERGED CULTURE BY B. SUBTILIS SPB1

Abstract

Nutritional requirements can contribute considerably to the production cost and the bioprocess economics. Media optimisation using response surface methodology is one of the used methods to ameliorate the bioprocess economics. In the present study, biosurfactant production by Bacillus subtilis SPB1 was effectively enhanced by response surface methodology. A Plackett–Burman-based statistical screening procedure was adopted to determine the most important factor affecting lipopeptide production. Eleven variables are screened and results show that glucose, K2HPO4 and urea concentrations influence the most biosurfactant production. A Central Composite Design was conducted to optimize the three selected factors. Statistical analyses of the data of model fitting were done by using SPSS and NemrodW software packages. Results show a maximum predicted biosurfactant concentration of 2.93 (±0.32) g/l, when using 15 g/l glucose, 7.5 g/l urea and 1 g/l K2HPO4. The predicted value is approximately 1.65 much higher than the original production determined by the conventional one-factor-at-a-time optimization method.