Rhamnolipid and lipase production by Pseudomonas aeruginosa san-ai: the process comparison analysis by statistical approach

Pseudomonas aeruginosa was repeatedly reported as powerful producer of rhamnolipid biosurfactants as well as producer of hydrolytic enzymes. In this study effects of four fermentation factors were evaluated using response surface methodology and experiments were performed in accordance with a four-factor and five-level central composite experimental design. Investigated factors were: fermentation temperature, time of fermentation, concentration of sunflower oil and concentration of Tween® 80. The most important finding was that regression coefficients of the highest values were those that describe interactions between factors and that they differ for lipase and rhamnolipid production, which were both investigated in this study. Production of both metabolites was optimized and response equations were obtained, making it possible to predict rhamnolipid concentration or lipase activity from known values of the four factors. The highest achieved rhamnolipid concentration and lipase activity were 138 mg dm-3 (sunflower oil concentration 0.8 %, Tween® 80 concentration 0.05 %, temperature 30°C, and fermentation time 72 h) and IU dm-3(sunflower concentration of 0.4 %, Tween® 80 concentration of 0.05 %, temperature of 30°C, and fermentation time of 120 h), respectively. [Projekat Ministarstva nauke Republike Srbije, br. E!6750 and br. III 46010