Journal of Applied Biosciences (J. Appl. Biosci.) [ISSN 1997 - 5902]
Volume 2: 46 - 53. Published February 2008.
Characterization of Alpha Amylase from Bacillus sp.1 isolated from paddy seeds
Varalakshmi KN*^, Kumudini BS, Nandini BN, Solomon JD, Mahesh B, Suhas R, Kavitha AP.
*Department of Biotechnology, Center for Post -Graduate Studies, Shri Bhagawan Mahaveer Jain College, 18/3, 9th Main, III Block, Jayanagar, Bangalore, India – 560 011
^Corresponding author email: varalakshmikn@yahoo.co.in; kumudini_satyan@yahoo.co.in
Telephone: 080-41502411; 080-41502415; 080-41210691; Fax No: 080- 41210692
ABSTRACT
Objective: This work was conducted with the aim of isolating promising α-amylase producing bacteria from different sources, using both solid-state and submerged fermentations.
Methodology and results: Two bacterial species were isolated from paddy seeds as promising candidates. The most promising one, Bacillus sp.1, was identified under submerged fermentation (SmF) and further characterized. Different carbon and nitrogen supplements were used to enhance production of the amylase enzyme. The maximum amount of enzyme was obtained with supplements of 1% starch or urea. Further attempts to enhance α-amylase production by Bacillus sp.1 were assessed by UV induced mutagenesis. One of the mutants (Bacillus sp.1m20) showed increased enzyme activity than the parental strain, Bacillus sp.1. However, the survival rate of this mutant decreased with increased duration of UV exposure. Partial purification of the enzyme using ammonium sulphate fractionation resulted in 1.06 fold increase in the enzyme activity. The enzyme had a molecular weight of ~ 40KDa by SDS-PAGE. The enzyme activity, which was optimal at 30°C and pH 6.8, was increased by the presence of Ca2+ and Co2+ ions.
Application of findings: The results suggest that Bacillus sp.1m20 could be exploited for industrial production of alpha amylase at relatively low temperatures.
Keywords: alpha amylase, Bacillus sp.1, submerged fermentation, mutagenesis, partial purification.
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