Amylolytic fungi in starter cakes for rice beer production.

Two types of starter cakes, viz. amou and perok-kushi, used in the production of rice beer in Assam, India, by the Bodo and Deori communities, respectively, were used for the isolation of amylolytic fungi. Based on the sequencing of their internal transcribed spacer (ITS) regions the fungi were identified as Amylomyces rouxii and Rhizopus oryzae, and given the strain names TU460 and TU465, respectively. Both the strains showed the ability to degrade and saccharify starch. The glucoamylase activity was considerably high in A. rouxii TU460 (14.92 μmol/min) as compared to R. oryzae TU465 (1.41 μmol/min), whereas α-amylase activity was found to be closely related, i.e. 7.02 and 6.09 unit mL-1, respectively. SDS PAGE for the determination of the molecular size of the glucoamylase enzymes revealed the production of two distinct units of 59 kDa and 31 kDa by A. rouxii TU460, and one unit of 72 kDa by R. oryzae TU465. LC MS/MS analysis revealed that no mycotoxins were produced by either of the strains. The overall study indicated a good amylolytic property of both strains and a potential for application in the starch processing industries.