Culture conditions and investigation of bioreactor configurations for lipase production by rhizopus oryzae

Abstract

Lipolytic enzymes are the subject of great industrial and academic interest. For this reason, a detailed study of lipolytic enzyme production by the fungus Rhizopus oryzae is tackled, and several steps from plate to shake flasks and bioreactor cultures are investigated in order to propose an optimized strategy to perform the biological process. The suitability of several lipidic compounds and surfactants is assessed. Triton X-100 (5 g/L) gives the highest activities with a maximum value of 6320 U/L which is 10-fold the value attained in cultures without addition of lipidic compounds. As there are almost no studies on bench-scale bioreactors, two bioreactor configurations, stirred tank and air-lift, are investigated to determine the most suitable one to carry out the biological reaction. It is demonstrated that the lipolytic activity is strongly enhanced when a stirred-tank bioreactor is used with a maximum value of 3521 U/L within two days which is clearly higher than the values produced by other recently reported species.