Sucrose secreted by the engineered cyanobacterium and its fermentability

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• 作者：Yangkai Duan ; Quan Luo ; Feiyan Liang ; Xuefeng Lu
• 关键词：Key wordspre ; treatment ; salt stress ; sps ; sucrose ; Synechococcus elongatus PCC 7942
• 刊名：Journal of Ocean University of China
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：15
• 期：5
• 页码：890-896
• 全文大小：545 KB
• 刊物主题：Oceanography; Meteorology;
• 出版者：Springer Berlin Heidelberg
• ISSN：1993-5021
• 卷排序：15

文摘

The unicellular cyanobacterium, Synechococcus elongatus PCC 7942 (Syn7942), synthesizes sucrose as the only compatible solute under salt stress. A series of engineered Syn7942 strains for sucrose production were constructed. The overexpression of the native sps (encoding a natively fused protein of sucrose phosphate synthase SPS and sucrose phosphate phosphatase SPP) in Syn7942 wild type caused a 93% improvement of sucrose productivity. The strain FL130 co-overexpressing sps and cscB (encoding a sucrose transporter) exhibited a 74% higher extracellular sucrose production than that overexpressing cscB only. Both results showed the significant improvement of sucrose productivity by the double functional protein SPS-SPP. Afterwards, FL130 was cultivated under a modified condition, and the cell-free culture medium containing 1.5 g L−1 sucrose was pre-treated with an acid hydrolysis technique. Cultivated with the neutralized hydrolysates as the starting media, two widely used microorganisms, Escherichia coli and Saccharomyces cerevisiae, showed a comparable growth with that in the control media supplemented with glucose. These results clearly demonstrated that the cell-free culture of sucrose-secreting cyanobacteria can be applied as starting media in microbial cultivation.