Optimization of amylase produced from bacteria isolated from cassava peel dumpsite using submerged fermentation

Abstract

The present investigation aimed at optimizing amylase production from amylolytic bacteria isolated from cassava peel dumpsite using submerged fermentation. Amylase production was carried out with four fermentation media designated as I, II, III and IV using all the bacteria isolated under static and non-static incubation condition for 24 h, at 37oC and pH 7. Fermentation conditions were optimized by varying the following parameters: pH (5-9), inoculum size (0.5-4.0%v/v), temperature (27-75ºC), substrate concentration of maize flour (medium I) (0.5-4.0 % w/v), starch concentration of medium III (0.5-4% w/v), incubation time (18-72 h), effect of carbon source on medium III (basal medium). The highest enzyme activity was exhibited by Enterobacter hormaechei SR3 and Bacillus cereus MR1. The effect of different media and the incubation condition on the amylase production were found to be significant (P˂ 0.05). Amylase production was found optimum at; pH of 7 and 8, and temperature of 50^OC and 60^OC, for a period of 48 and 72 h of incubation, 2.0 and 3.0 %w/v concentration of maize flour and starch respectively. Maximum enzyme produced in maize flour by Bacillus cereus MR1 was 2.668 ±0.003U/mL/min and 2.718±0.001 U/mL/min by Enterobacter hormaechei SR3 in basal medium III. The results showed that maize flour is a good substrate for amylase production and enzymes produced by this study can be used for industrial purposes.