title: Effect of partial pressure of CO2 on the production of thermostable alpha-amylase and neutral protease by Bacillus caldolyticus.
abstract: Controlling the concentration of dissolved oxygen is a standard feature in aerobic fermentation processes but the measurement of dissolved CO2 concentrations is often neglected in spite of its influence on the cellular metabolism. In this work room air and room air supplemented with 5% and 10% carbon dioxide were used for aeration during the cultivation of the thermophilic microorganism Bacillus caldolyticus (DSM 405) on starch to produce alpha-amylase (E.C. 3.2.1.1) and neutral protease (E.C. 3.4.24.27/28). The increased CO2 concentrations resulted in a 22% raise in activity of secreted alpha-amylase and a 43% raise in protease activity when compared with aeration with un-supplemented room air. There was no effect on the final biomass concentration. Furthermore, the lag-phase of fermentation was reduced by 30%, further increasing the productivity of alpha-amylase production. Determinations of dissolved CO2 in the culture broth were conducted both in situ with a probe as well as using exhaust gas analysis and both the methods of quantification showed good qualitative congruence.
authors.affiliation: Technische Universität Berlin, Fakultät III, Biotechnologie, Department of Applied and Molecular Microbiology, Berlin 13353, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Bader
authors.forename: L
authors.initials: L
authors.lastname: Skelac
authors.forename: S
authors.initials: S
authors.lastname: Wewetzer
authors.forename: M
authors.initials: M
authors.lastname: Senz
authors.forename: M K
authors.initials: MK
authors.lastname: Popović
authors.forename: R
authors.initials: R
authors.lastname: Bajpai
mesh_terms: D001407:Bacillus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism; D004795:Enzyme Stability; D005285:Fermentation; D007218:Industrial Microbiology; D010313:Partial Pressure; D010447:Peptide Hydrolases / Q000378:metabolism*; D013213:Starch / Q000378:metabolism*; D000516:alpha-Amylases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002245:Carbon Dioxide; D013213:Starch; D000516:alpha-Amylases; D010447:Peptide Hydrolases