Improvement of intracellular beta-galactosidase production in fed-batch culture of Kluyveromyces fragilis

• Published in: Biotechnology letters Vol. 23; no. 11; pp. 845 - 849
• Main Authors: Nor, Z.M, Tamer, M.I, Mehrvar, M, Scharer, J.M, Moo-Young, M, Jervis, E.J
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01-06-2001
• Subjects: beta-galactosidase; Biological and medical sciences; Biotechnology; dissolved oxygen; Enzyme engineering; Fermentation; fermenters; Fundamental and applied biological sciences. Psychology; Kluyveromyces fragilis; Kluyveromyces marxianus; Methods. Procedures. Technologies; Production of selected enzymes; specific growth rate; temperature; Microorganism growth; Yeast; On line; Enzyme; Optimization; Fungi; Enzymatic activity; Glycosidases; Production; Microorganism culture; Hydrolases; Ascomycetes; Intracellular; O-Glycosidases; Semicontinuous; Monitoring; β-Galactosidase; Thallophyta
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1023/A:1010526831985

Four fed-batch control strategies were evaluated to improve the specific lactase activity of Kluyveromyces fragilis. Control strategies tested included DO-stat control, exponential feeding, exponential feeding with manual feedback control and corrected feed-forward control. Each was implemented with standard sensors (i.e., temperature, dissolved oxygen and pH sensors) commonly installed in fermenters. The highest specific activity was obtained using the corrected feed-forward control strategy, a strategy incorporating a novel method for on-line estimation of specific growth rate. The control strategy was able to operate effectively to a final cell density of 69 g dry wt l(-1) with a specific lactase activity of 2 U mg(-1) cell dry wt.