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. © Springer-Verlag and the University of Milan 2011.