摘要
为获得古罗糖醛酸(Guluronate)含量高的细菌胞外褐藻多糖,利用PCR从海洋细菌Pseudomonassp.QDA中克隆了其甘露糖醛酸C-5差向异构酶基因(algG),连接入质粒pMF 54Km,构建了重组表达载体pMF54 Km-algG。利用三亲接合法将pMF54 Km-algG转入菌株QDA中,获得algG过量表达重组菌株QDA-G1。H-NMR测定结果表明,QDA-G所产的褐藻多糖中β-D-甘露糖醛酸(M)与它的C-5差向异构体α-L-古罗糖醛酸(G)的比值为0.38,G的质量分数达到74.2%,比野生菌株QDA提高了26.4%。且重组菌株遗传稳定性良好,连续传代20代后,M/G的比值无明显变化。
Pseudomonas sp. QDA, which was isolated from seawater, has the ability of producing extracellular alginate. In order to obtain the high-guluronate-containing alginate, C-5-mannuronan epimerase gene （algG） of Pseudomonas sp. QDA was cloned by PCR and ligated in to plasmid pMF54Km. The resulting plasmid pMF54Km-algG was transferred to QDA by triparental mating, and an algG over-expresslng strain, QDA-G, was obtained. The results of 1H-NMR showed that the M/G ratio of alginate fragments by QDA-G was 0.38 and the content of guluronate was 74.2%, about 26.4% higher than that of wild strain QDA. The genetic stability of QDA-G was good. No significant changes were found in M/G ratio of algi- nate fragments of QDA-G after 20 passages.
出处
《海洋科学》
CAS
CSCD
北大核心
2008年第1期14-18,共5页
Marine Sciences
基金
国家自然科学基金资助项目(30371683)
