Enhancement of polysialic acid yield by reducing initial phosphate and feeding ammonia water to Escherichia coli CCTCC M208088

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Publisher: Springer
Document Type: Report
Length: 174 words

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Byline: Jian-Rong Wu (1), Jin-Long Liu (1), Xiao-Bei Zhan (1), Chi-Chung Lin (1), Hui Zhao (1) Keywords: polysialic acid; Escherichia coli; phosphate; ammonia Abstract: Polysialic acid (PSA) is a capsular polysaccharide obtained from aerobic fermentation with Escherichia coli. To enhance PSA production and eliminate the influence of phosphate on the PSA purification process, a lower level of initial phosphate was adopted with pH control. The resulting PSA yield reached 4.1 g/L in fed-batch fermentation with 2.5 g/L [K.sub.2]HPO.sub.4 and E. coli strain CCTCC M208088. In addition, an ammonia water (N[H.sub.4]OH) feeding strategy to control the pH at 6.4 was developed resulting in PSA production that reached as high as 5.2 g/L. NMR spectra confirmed the purified biopolymer as a [alpha]-2,8 linked PSA, identical to the published NMR spectra, with a molecular weight in the range of 16 [proportional to] 50 kDa. Author Affiliation: (1) Key Laboratory of Industrial Biotechnology, School of Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214-122, China Article History: Registration Date: 03/09/2009 Received Date: 23/11/2009 Accepted Date: 19/01/2010 Online Date: 09/09/2010

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Gale Document Number: GALE|A236714915