The change of the state of cell membrane can enhance the synthesis of menaquinone in Escherichia coli
The change of the state of cell membrane can enhance the synthesis of menaquinone in Escherichia coli
复制标题
细胞膜状态的改变可增强大肠杆菌内甲基萘醌的合成
DOI：
10.1007/s11274-017-2222-9
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发表时间：
2017-03-01
影响因子：
4.1
通讯作者：
Zheng, Zhi-ming
中科院分区：
文献类型：
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作者：
Liu, Yan;Ding, Xiu-min;Zheng, Zhi-ming
甲基萘醌（MK）是一种具有吸引力的膜结合细胞内化学物质。为了提高其产量，我们试图找出其合成与生产菌株细胞膜状态的关系。由于非离子型表面活性剂聚氧乙烯油基醚（POE）和植物油雪松木油（CWO）分别能显著促进MK的胞外分泌和胞内合成，研究了这两种物质对细胞形态、细胞膜物理性质的影响。最后，构建了两株工程菌，以验证细胞膜状态是否能促进MK合成。结果表明，POE的加入使细胞边缘断裂。其他物理性质如总脂肪酸含量下降40.7%，饱和脂肪酸与不饱和脂肪酸的比例从1.58 ± 0.05下降到1.31 ± 0.04。细胞膜透性从7.14%增加到64.31%。与POE组不同，CWO组细胞膜完整。此外，饱和脂肪酸与不饱和脂肪酸的比值从1.58 ± 0.05增加到1.78 ± 0.04，平均脂质长度从16.05 ± 0.08减少到15.99 ± 0.10。两株构建菌株均表现出较强的MK分泌能力，其中大肠杆菌DH 5 α FatB分泌能力最强，胞外MK达10.71 ± 0.19mg/L。对这些作用机制的理解不仅可以为MK的合成提供新的思路，而且可以为提高胞内膜结合代谢产物的产量提供参考。
Menaquinone (MK) was an attractive membrane-bound intracellular chemical. To enhance its production, we tried to find the relationship between its synthesis and the state of cell membrane in producing strain. Due to non-ionic surfactant-polyoxyethylene oleyl ether (POE) and plant oil-cedar wood oil (CWO) can typically increase extracellular secretion and intracellular synthesis of MK respectively, the effect of these two substances on cell morphology, physical properties of cell membrane was investigated. Finally, two engineering strains were constructed to verify whether the state of cell membrane can enhance MK synthesis. The result showed that the edge of cells was broken when POE added in the medium. Other physical properties such as total fatty acid content decreased by 40.7% and the ratio of saturated fatty acids to unsaturated fatty acids decreased from 1.58 ± 0.05 to 1.31 ± 0.04. Meanwhile, cell membrane leakage was enhanced from 7.14 to 64.31%. Different from POE group, cell membrane was intact in CWO group. Moreover, the ratio of saturated fatty acids to unsaturated fatty acids increased from 1.58 ± 0.05 to 1.78 ± 0.04 and the average lipid length decreased from 16.05 ± 0.08 to 15.99 ± 0.10. Two constructed strains, especially Escherichia coli DH5α FatB, exhibited strong MK secretion ability and the extracellular MK reached 10.71 ± 0.19 mg/L. An understanding of these functionary mechanisms could not only provide a new idea for the synthesis of MK, but also provide a reference to increase the yield of intracellular membrane-bound metabolites.