Inulinase production by Saccharomyces sp. in solid state fermentation using wheat bran as substrate

Abstract

A newly isolated inulinase-producing Saccharomyces sp. from spontaneously fermented sugar cane was employed for inulinase production in solid state fermentation. All the substrates used—wheat bran, rice bran, banana peel, orange peel and bagasse—supported inulinase production. However, the highest inulinase production (78.29 ± 0.13 U/g ds, units per gram of dry substrate) was recorded with wheat bran, while orange bagasse gave the lowest inulinase production (22.47 ± 0.01 U/g ds). A time course of inulinase production revealed that maximum inulinase production of 90.15 U/g ds was reached at 72 h of fermentation. A 24-h-old inoculum and an inoculum density of 4% was also found to be optimal, yielding inulinase production of 88.5 ± 0.02 U/g ds and 80.9 ± 0.25 U/g ds, respectively, by the Saccharomyces sp. Furthermore, a moisture content of 65% was found to support maximum inulinase production of 81.5 ± 0.02 U/g ds. pH and temperature studies showed pH 5.5 and 35°C to be optimum for inulinase production of 91.0 ± 0.60 U/g ds and 89.5 ± 0.06 U/g ds, respectively, by this Saccharomyces sp.