A comparative study on alkaline lipase production by a newly isolated Aspergillus fumigatus MTCC 9657 in submerged and solid-state fermentation using economically and industrially feasible substrate

Abstract

A comparative study of solid-state fermentation (SSF) and submerged fermentation (SmF) for the production of alkaline lipase from a new isolate, Aspergillus fumigatus MTCC 9657, using defatted rice bran (DFRB) as a substrate was studied. Diff erent process parameters, such as incubation period, initial pH and incubation temperature, were optimised to achieve the maximum yield of the alkaline lipase. Maximum enzyme production (8.13 U/mL) was obtained by day 7 of incubation in SSF compared to day 4 in SmF at an optimum pH of 8.5 and ambient temperature of 30 °C. Lipase produced by SSF was stable over a period of 15 days, whereas lipase production in SmF decreased by day 5. Lipase production in SSF with DFRB using sterile water as a moisture source exhibited more activity (577.5 U/70 mL) than that supplemented with mineral medium. Compared to the cost of culture medium, the solid-state substrate DFRB is inexpensive, and therefore this process is industrially and economically feasible. Th ese results confi rm the interesting potential of SSF in DFRB without any additional nutritional supplement. ©TÜBİTAK.