Production and properties of alpha-amylase from Bacillus sp. BKL20.
As a result of screening Bacillus sp. strains isolated from different natural substrates, strain BKL20 was identified as a producer of a thermostable alkaline alpha-amylase. Maximum production of this alpha-amylase was achieved by optimizing culture conditions. Production of alpha-amylase seemed to be independent of the presence of starch in the culture medium and was stimulated by the presence of peptone (0.3%, m/v) and yeast extract (0.2%, m/v). The enzyme was thermostable and retained amylolytic activity after 30 min of incubation at 60 and 70 degrees C. High activity was maintained over a broad pH range, from 6.0 to 11.0, and the enzyme remained active after alkaline incubation for 24 h. Bacillus sp. BKL20 alpha-amylase was not stimulated by Ca2+ or other bivalent metal cations and was not inhibited by EGTA or EDTA at 1-10 mmol/L, suggesting that this alpha-amylase is a Ca2+-independent enzyme. It also showed good resistance to both oxidizing (H2O2) and denaturating (urea) agents.
Kubrak
Olha I
OI
Department of Biochemistry, Vassyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine.
Storey
Janet M
JM
Storey
Kenneth B
KB
Lushchak
Volodymyr I
VI
D001407:Bacillus / Q000201:enzymology* / Q000254:growth & development / Q000302:isolation & purification; D002118:Calcium / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004795:Enzyme Stability; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D010461:Peptones / Q000378:metabolism; D013213:Starch / Q000378:metabolism; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism
D003470:Culture Media; D010461:Peptones; D013213:Starch; D006861:Hydrogen Peroxide; D000516:alpha-Amylases; D002118:Calcium