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Optimum Production and Characterization of Thermostable Amylolytic Enzymes from B. stearothermophilus GRE1
Author(s) -
Hossain S. M. Z.,
Haki G. D.,
Rakshit S. K.
Publication year - 2006
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450840313
Subject(s) - enzyme , production (economics) , geobacillus stearothermophilus , characterization (materials science) , biochemistry , chemistry , thermophile , materials science , economics , microeconomics , nanotechnology
Optimum production of extracellular, thermostable amylolytic enzymes (α and β‐amylase) by a newly isolated bacterium, Bacillus stearothermophilus , was investigated in a batch bioreactor. Starch and lactose at 1.0% and 3.0% (w/v) respectively were found to be optimum for maximum enzyme production. Optimization of cultural conditions (pH 7.0 and temperature 45°C) resulted in high bacterial specific growth rate (0.64 h −1 ), yielding 2.20 gL −1 biomass, 11.43 UmL −1 α‐amylase and 10.04 UmL −1 of β‐amylase. Hydrolysis of native starches from wheat, cassava, corn and potato at 60°C using the crude enzyme showed 60‐80% saccharification with potato starch showing the least and wheat starch showing the greatest hydrolysis. The K m and V max values of the crude α‐amylase for starch were 4.78 mg starch/mL and 6.67 mg/mL.min respectively.