Oxygen transfer effects in β-lactamase fermentation by Bacillus licheniformis in a glucose-based defined medium

✍ Scribed by Dr Pınar Çalık; Müge Arifoǧlu; Güzide Çalık

• Book ID: 102314982
• Publisher: Wiley (John Wiley & Sons)
• Year: 2005
• Tongue: English
• Weight: 200 KB
• Volume: 80
• Category: Article
• ISSN: 0268-2575
• DOI: 10.1002/jctb.1284

✦ Synopsis

Abstract

The effects of oxygen transfer on the β‐lactamase production by Bacillus licheniformis were investigated in a glucose‐based defined medium. The experiments were conducted in 3.0 dm^3^ batch bioreactor systems at three different air inlet (Q~O~/V~R~ = 0.2, 0.5 and 1.0 vvm) and agitation rates (N = 250, 500 and 750 min^−1^). During the fermentation, the concentrations of the cell, glucose, by‐products, ie organic and amino acids, oxygen transfer coefficients (K~L~a), yield coefficients, specific rates and oxygen uptake rates (OUR) were determined, in addition to β‐lactamase activities. The highest β‐lactamase activity was obtained at Q~O~/V~R~ = 0.5 vvm and N = 500 min^−1^ and at Q~O~/V~R~ = 0.2 vvm and N = 500 min^−1^ conditions, as ca A = 90 U cm^−3^. The highest cell concentration was obtained as C~X~ = 0.67 kg m^−3^ at Q~O~/V~R~ = 0.5 vvm and N = 750 min^−1^ and at Q~O~/V~R~ = 0.2 vvm and N = 750 min^−1^ conditions. The values of K~L~a increased with increasing agitation and aeration rates and varied between 0.007 and 0.044 s^−1^, and the OUR varied between 0.4 and 1.6 mol m^−3^ s^−1^. With increasing Q~O~/V~R~ and/or N, the Damköhler number (ie the oxygen transfer limitation) decreased owing to the increase in mass transfer coefficients (K~L~a). The highest instantaneous yield of cell on substrate (Y~X/S~) and yield of cell on oxygen (Y~X/O~) values were respectively obtained at 0.5 vvm and 500 min^−1^ conditions at t = 2 h as Y~X/S~ = 0.72 kg kg^−1^ and Y~X/O~ = 1.49 kg kg^−1^. The highest instantaneous yield of substrate on oxygen (Y~S/O~) was obtained at 0.5 vvm and 750 min^−1^ conditions at t = 20 h as Y~S/O~ = 8.07 kg kg^−1^. Copyright © 2005 Society of Chemical Industry