Identification of key genes involved in polysaccharide bioflocculant synthesis in Bacillus licheniformis
Identification of key genes involved in polysaccharide bioflocculant synthesis in Bacillus licheniformis
复制标题
地衣芽孢杆菌多糖生物絮凝剂合成关键基因的鉴定
DOI：
10.1002/bit.26189
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发表时间：
2017-03-01
影响因子：
3.8
通讯作者：
He, Ning
中科院分区：
文献类型：
--
作者：
Chen, Zhen;Liu, Peize;He, Ning
本研究报道了地衣芽孢杆菌CGMCC 2876的基因组序列，该基因组由一条4284461 bp的染色体组成，包含4188个蛋白质编码基因、72个tRNA基因和21个rRNA基因。进一步分析发现eps基因簇有16个开放阅读框。保守域数据库分析结合qPCR实验表明，该簇中的所有基因都参与了多糖生物絮凝剂的合成。磷酸葡萄糖糖化酶和udp -葡萄糖焦磷酸化酶被认为是地衣双歧杆菌分泌多糖的关键酶。在功能分析的基础上，提出了一种涉及个体基因整合的多糖生物絮凝剂的生物合成途径。在地衣芽孢杆菌CGMCC 2876中过表达eps基因簇中的epsDEF，重组菌株的絮凝活性比原菌株提高了90%。多糖生物絮凝剂粗收率提高27.8%。过表达udp -葡萄糖焦磷酸化酶基因不仅使絮凝活性提高了71%，而且使生物絮凝剂产量提高了13.3%。不依赖于udp - n -乙酰氨基- d -甘露糖胺脱氢酶基因的udp - n -乙酰氨基- 2-epimerase基因的过表达会对絮凝活性和多糖产量产生负面影响。综上所述，epsDEF和gtaB2是地衣芽孢杆菌合成多糖生物絮凝剂的关键基因。这些结果将为地衣芽孢杆菌的进一步工程应用于工业生物絮凝剂生产提供参考。Biotechnol。Bioeng。2017;114: 645 - 655。(c) 2016 Wiley Periodicals, Inc.；
The present study reports the sequenced genome of Bacillus licheniformis CGMCC 2876, which is composed of a 4,284,461bp chromosome that contains 4,188 protein-coding genes, 72 tRNA genes, and 21 rRNA genes. Additional analysis revealed an eps gene cluster with 16 open reading frames. Conserved Domains Database analysis combined with qPCR experiments indicated that all genes in this cluster were involved in polysaccharide bioflocculant synthesis. Phosphoglucomutase and UDP-glucose pyrophosphorylase were supposed to be key enzymes in polysaccharide secretion in B. licheniformis. A biosynthesis pathway for the production of polysaccharide bioflocculant involving the integration of individual genes was proposed based on functional analysis. Overexpression of epsDEF from the eps gene cluster in B. licheniformis CGMCC 2876 increased the flocculating activity of the recombinant strain by 90% compared to the original strain. Similarly, the crude yield of polysaccharide bioflocculant was enhanced by 27.8%. Overexpression of the UDP-glucose pyrophosphorylase gene not only increased the flocculating activity by 71% but also increased bioflocculant yield by 13.3%. Independent of UDP-N-acetyl-D-mannosamine dehydrogenase gene, flocculating activity, and polysaccharide yield were negatively impacted by overexpression of the UDP-N-acetylglucosamine 2-epimerase gene. Overall, epsDEF and gtaB2 were identified as key genes for polysaccharide bioflocculant synthesis in B. licheniformis. These results will be useful for further engineering of B. licheniformis for industrial bioflocculant production. Biotechnol. Bioeng. 2017;114: 645-655. (c) 2016 Wiley Periodicals, Inc.