Abstract

Production of raw starch degrading amylase by a mixed culture of Aspergillus niger and Saccharomyces cerevisae grown on sorghum pomace as nutrient source was investigated.  Effect of mineral nutrient supplementation of sorghum pomace on raw starch degrading amylase activity was also determined. Sorghum pomace medium significantly (P<0.05) induced higher level of raw and extracellular amylase than soluble starch medium.  Mixed culture media recorded higher (P<0.05) level of raw starch degrading amylase than monoculture media. However, mineral nutrient supplementation significantly (P<0.05) suppressed raw starch degrading amylase production. The crude enzyme solution degraded both cereal and tuber or root starches significantly (P<0.05). Sources of crude enzyme significantly (P<0.05) influenced raw starch digesting activity.  Optimum pH for the raw starch degrading amylase which varied between 3.0 and 8.0 depended on the source of the crude enzyme.

Key words: Raw starch, Amylase, Aspergillus niger, Saccharomyces cerevisae,Sorghum pomace.