Characterization and Optimization of Amylase Production in WangLB, a High Amylase-Producing Strain of Bacillus.
The costs of amylase represent ca. 24 % of the expenditures in the starch industry and an increase in amylase production and/or activity will greatly cut down on production costs. In the present study, we obtained a high amylase-producing strain of bacteria, WangLB, and identified it as a member of the Bacillus genus based on 16S rDNA analysis. The fermentation conditions for amylase production in the strain were optimized, and the maximum amylase activity we obtained was 26,670 ± 1390 U/mL, under the optimized conditions of 48-h incubation in liquid starch medium, 35 °C, pH 10, 1 % v/v inoculum concentration, 20 g/L starch concentration, and 0.1 % w/v peptone. The influences of 16 small organic inducers on amylase production were tested, and the results showed that 20 mmol/L alanine greatly enhanced amylase production to 290 % of the baseline level. We also conducted an amylase enzymology analysis. The molecular weight of the amylase was 55 kD, determined by SDS-PAGE. The optimum temperature and pH for the amylase were 55 °C and pH 9, respectively. The enzyme also showed high activity over a wide range of temperatures (50-85 °C) and pH values (3-10), and the activity of the amylase was Ca(2+) independent. The kinetic parameters K m and V max were 0.37 ± 0.02 mg/mL and 233 U/mg, respectively. Finally, the amylase was applied to the hydrolysis of five different brands of starch. It was found that the hydrolyzability of the substrate by amylase increased along with starch solubility.
Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.|Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
Shihui
S
Wang
Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada.
Jenasia
J
Jeyaseelan
Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
Yun
Y
Liu
Department of Biology, Lakehead University, 955 Oliver Road, Thunder Bay, Ontario, P7B 5E1, Canada. wqin@lakeheadu.ca.
Wensheng
W
Qin
D000681:Amylases / Q000096:biosynthesis*; D001407:Bacillus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D001483:Base Sequence; D001709:Biotechnology / Q000379:methods*; D004275:DNA, Ribosomal / Q000235:genetics; D003902:Detergents / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005285:Fermentation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007477:Ions; D007700:Kinetics; D008670:Metals / Q000494:pharmacology; D009584:Nitrogen / Q000494:pharmacology; D010461:Peptones / Q000494:pharmacology; D010802:Phylogeny; D012997:Solvents / Q000494:pharmacology; D013213:Starch / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors
D004275:DNA, Ribosomal; D003902:Detergents; D007477:Ions; D008670:Metals; D010461:Peptones; D012997:Solvents; D013213:Starch; D000681:Amylases; D009584:Nitrogen
Amylase; Bacillus sp; Enzymology; Fermentation parameters