Evaluation of Ca-independent a-amylase production by Bacillus sp. KR-8104 in submerged and solid state fermentation systems

This study investigates the production of crude Ca-independent and low pH active a-amylase by Bacillus sp. KR-8104 in submerged fermentation (SmF) and solid-state fermentation (SSF) systems. Different parameters were evaluated in each system using “one factor at a time” approach to improve the production of enzyme. The results showed that in the SmF the maximum enzyme production was achieved in culture medium that contained dextrin as a carbon source, as well as yeast extract and meat extract as nitrogen sources incubated at 37ºC and 180 rpm for 48 h. While SSF of Bacillus sp. KR-8104 using wheat bran (WB) as a substrate showed that using tap water or distilled water as a moisturizing agent, a substrate-water ratio of 1:1.5 (w/v) and incubation at 37ºC for 48 h gave the maximum a-amylase production. From different extraction medium examined in this study 0.1% (v/v) aqueous mixture of Tween 20 and distilled water illustrated maximum results (~100 U/g).