Background: Poly-3-hydroxybutyrate (PHB) can be efficiently produced in recombinant Escherichia coli by the overexpression of an operon ( NphaCAB ) encoding PHB synthetase. Strain improvement is considered to be one of critical factors to lower the production cost of PHB in recombinant system. In this study, one of key regulators that affect the cell growth and PHB content was confirmed and analyzed. Result: S17-3, a mutant E. coli strain derived from S17-1, was found to be able to achieve high cell density when expressing NphaCAB with the plasmid pBhya-CAB. Whole genome sequencing of S17-3 revealed genetic alternations on the upstream regions of csrA , encoding a global regulator cross-talking between stress response, catabolite repression and other metabolic activities. Deletion of csrA or expression of mutant csrA resulted in improved cell density and PHB content. Conclusion: The impact of gene deletion of csrA was determined, dysfunction of the regulators improved the cell density of recombinant E. coli and PHB production, however, the detail mechanism needs to be further clarified. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; line-height:107%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

中文翻译：

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通过删除大肠杆菌中的 csrA 提高聚羟基丁酸产量

背景：通过过度表达编码 PHB 合成酶的操纵子 (NphaCAB)，可以在重组大肠杆菌中有效地生产聚 3-羟基丁酸 (PHB)。菌株改良被认为是降低重组系统中PHB生产成本的关键因素之一。在这项研究中，确认和分析了影响细胞生长和 PHB 含量的关键调节因子之一。结果：发现 S17-3 是一种源自 S17-1 的突变大肠杆菌菌株，当用质粒 pBhya-CAB 表达 NphaCAB 时，能够实现高细胞密度。S17-3 的全基因组测序揭示了 csrA 上游区域的遗传改变，编码了应激反应、分解代谢物抑制和其他代谢活动之间的全局调节器串扰。csrA 的缺失或突变体 csrA 的表达导致细胞密度和 PHB 含量的提高。结论：csrA基因缺失的影响已确定，调节因子的功能障碍提高了重组大肠杆菌细胞密度和PHB的产生，但具体机制有待进一步阐明。正常 0 false false false EN-US X-NONE X-NONE /* 样式定义 */ table.MsoNormalTable {mso-style-name:"Tabla normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow：是；mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:8.0pt; mso-para-margin-left:0cm; 行高：107%；mso-分页：寡妇孤儿；字体大小：11.0pt; font-family:"Calibri",sans-serif; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}