Positive effect of reduced aeration rate on secretion of alpha-amylase and neutral proteases during pressurised fermentation of thermophilic Bacillus caldolyticus.
The thermophilic microorganism Bacillus caldolyticus was incubated in laboratory scale stirred bioreactors under pressurised conditions at different aeration rates. Increased amounts of CO2/bicarbonate were solubilised under the chosen conditions. A reduction in aeration rate from 1 vvm to 0.1 vvm resulted in accumulation of CO2 and bicarbonate up to 126 mg l(-1) and 733 mg l(-1), respectively and also increased secretion of α-amylase and neutral proteases (increases of 123% and 52%, respectively). In this paper, the effect of reduced aeration rate on CO2/bicarbonate concentration and enzyme activities is presented. The selected fermentation conditions are closely related to those prevalent in large scale bioreactors and may offer the possibility of achieving high enzyme yields at reduced aeration costs on an industrial scale.
Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany. Electronic address: popovic@beuth-hochschule.de.
M K
MK
Popović
Institute of Biotechnology, University of Technology, Seestraße 13, 13353 Berlin, Germany.
M
M
Senz
Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany.
J
J
Bader
Research Institute of Brewing, Seestraße 13, 13353 Berlin, Germany.
L
L
Skelac
Institute of Biotechnology, Beuth University of Applied Sciences, Seestraße 64, 13347 Berlin, Germany.
W
W
Schilf
Chemical Engineering Department, University of Louisiana at Lafayette, Lafayette, LA 70508, USA.
R
R
Bajpai
D001407:Bacillus / Q000254:growth & development*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D001639:Bicarbonates / Q000378:metabolism; D019149:Bioreactors; D002245:Carbon Dioxide / Q000378:metabolism; D010447:Peptide Hydrolases / Q000096:biosynthesis*
D001426:Bacterial Proteins; D001639:Bicarbonates; D002245:Carbon Dioxide; D010447:Peptide Hydrolases