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

Document Type : Research Paper


1 Department of Food Science and Engineering, Faculty of Agricultural Engineering and Technology, University of Tehran, P.O. Box 4111, Karaj, I.R. Iran.

2 Department of Microbial Biotechnology and Biosafety, Agricultural Biotechnology Research Institute of Iran (ABRII), P.O. Box 31535-1897, Karaj, I.R. Iran.

3 Biotechnology Group, Chemical Engineering Department, Tarbiat Modares University, P.O. Box 14115-143, Tehran, I.R. Iran.


This study investigates the production of crude Ca-independent and low pH active α-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 α-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).