Abstract
In this article, we report the optimization of bacterial extracellular alpha amylase production from Bacillus amyloliquefaciens IIB-14, a locally isolated bacterial culture, using response surface methodology (RSM). Different agricultural by-products were evaluated for enzyme activity under solid state fermentation (SSF). Of those, wheat bran (10 g) was found to be optimal when moistened with 0.02 M phosphate buffer at a level of 1:1.25. A marked improvement in enzyme productivity (52.06 U/mg/min) was observed at 72 h after the cultivation at 40°C (pH 7.2). The pre-grown bacterial inoculum (24 h old) was used at a level of 20%, v/v. The combined effect of cultural and nutritional variables on bacterial amylase was further investigated using RSM. The procedure limited the number of actual experiments performed while allowing for possible interactions between the optimal components including temperature, pH and inoculum. No previous work has used statistical analysis in determining the interactions among these parameters for alpha amylase production. The p-value of the coefficient for quadratic effect was 0.002, suggesting that this was the principal experimental variable having maximal effect on enzyme productivity. The results are economically significant (p ≤ 0.05) and marked the commercial utility of the isolated bacterial culture. Key words: Agricultural by-products, alpha amylase, Bacillus spp., fermentation, response surface methodology, solid substrate fermentation.
Highlights
Alpha amylase is an extra-cellular endo-enzyme that randomly cleaves α-1,4 linkages between adjacent glucose units in the linear amylose and branched amylopectin chain of the starch molecule and generates glucose, maltose and maltotriose units (Dey et al, 2001; Liu and Xun, 2008)
We report the optimization of bacterial extracellular alpha amylase production from Bacillus amyloliquefaciens Industrial Biotechnology (IIB)-14, a locally isolated bacterial culture, using response surface methodology (RSM)
The strain Bacillus amyloliquefaciens IIB-14, a locally isolated bacterial culture was obtained from the available stock culture of the Institute of Industrial Biotechnology (IIB), Government College University Lahore Pakistan
Summary
Alpha amylase (endo-1,4-α-D-glucan glucanohydrolase) is an extra-cellular endo-enzyme that randomly cleaves α-1,4 linkages between adjacent glucose units in the linear amylose and branched amylopectin chain of the starch molecule and generates glucose, maltose and maltotriose units (Dey et al, 2001; Liu and Xun, 2008). Alpha amylase constitutes approximately 25% of the world enzyme market covering many industrial processes such as sugar, textile, paper, brewing, baking, distilling industries, preparation of digestive aids, fruit juices, starch syrups, detergents and pharmaceuticals (Teodoro and Martins, 2000; Hmidet et al, 2009). These applications have stressed to search a better fermentation process for enzyme productivity. The limitation of a single factor optimization can be eliminated by different techniques such as response surface methodology (RSM) which is used to explain the combined effects of all the variables involved. The present study was designed to evaluate different agricultural by-products like rice bran, maize bran, rice husk, wheat bran, barley bran, mustered cakes and wheat straw and to optimize the cultural conditions such as incubation period, temperature, pH, moisture content, size and age of inoculum for alpha amylase productivity from Bacillus amyloliquefaciens IIB14 under SSF
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
