High cell density cultivation of Escherichia coli K4 in a microfiltration bioreactor: a step towards improvement of chondroitin precursor production

Microbial Cell Factories

Research

Mario De Rosa¹  Chiara Schiraldi¹  Angela Catapano¹  Odile Francesca Restaino¹  Mario De Rosa¹  Donatella Cimini¹ 

[1] Department of Experimental Medicine, Section of Biotechnology and Molecular Biology, Second University of Naples, 80138, Naples, Via de Crecchio 7, Italy;

关键词: Capsular Polysaccharide;    Acetate Concentration;    High Cell Density Cultivation;    Shake Flask Experiment;    Feeding Profile;   

DOI  :  10.1186/1475-2859-10-10

 received in 2010-10-01, accepted in 2011-02-16,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundThe bacteria Escherichia coli K4 produces a capsular polysaccharide (K4 CPS) whose backbone is similar to the non sulphated chondroitin chain. The chondroitin sulphate is one of the major components of the extra-cellular matrix of the vertebrate connective tissues and a high value molecule, widely employed as active principle in the treatment of osteoarthritis. It is usually obtained by extraction from animal tissues, but the risk of virus contaminations, as well as the scarceness of raw material, makes this productive process unsafe and unable to satisfy the growing market demand. In previous studies a new biotechnological process to produce chondroitin from Escherichia coli K4 capsular polysaccharide was investigated and a 1.4 g·L-1 K4 CPS concentration was reached using fed-batch fermentation techniques. In this work, on the trail of these results, we exploited new fermentation strategies to further improve the capsular polysaccharide production.ResultsThe inhibitory effect of acetate on the bacterial cells growth and K4 CPS production was studied in shake flask conditions, while a new approach, that combined the optimization of the feeding profiles, the improvement of aeration conditions and the use of a microfiltration bioreactor, was investigated in three different types of fermentation processes. High polysaccharide concentrations (4.73 ± 0.2 g·L-1), with corresponding average yields (0.13 ± 0.006 gK4 CPS·gcdw-1), were obtained; the increase of K4 CPS titre, compared to batch and fed-batch results, was of 16-fold and 3.3-fold respectively, while average yield was almost 3.5 and 1.4 fold higher.ConclusionThe increase of capsular polysaccharide titre confirmed the validity of the proposed fermentation strategy and opened the way to the use of the microfiltration bioreactor for the biotechnological production of chondroitin.

【 授权许可】

Unknown   
© Restaino et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.