Increasing unsaturated fatty acid contents in Escherichia coli by coexpression of three different genes
Increasing unsaturated fatty acid contents in Escherichia coli by coexpression of three different genes
复制标题
DOI：
10.1007/s00253-009-2377-x
复制
发表时间：
2010-06-01
影响因子：
5
通讯作者：
Liu, Wei
中科院分区：
文献类型：
--
作者：
Cao, Yujin;Yang, Jianming;Liu, Wei
生物柴油是一种有趣的替代能源，被用作石油柴油的替代品。微生物因其显著的环境效益和经济效益而被用于生物柴油的生产。然而，很少有研究研究这些微生物柴油的脂肪酸组成的调节。大肠杆菌中脂肪酸的生物合成为其他细菌和植物提供了一个范例。通过在大肠杆菌中过表达两个与不饱和脂肪酸(UFA)合成相关的基因(FabA和Fabb)，我们已经设计出了一个高效的UFAs产生者。饱和脂肪酸(SFA)含量从对照菌株的50.2%降至34.6%(同时高表达蚕豆和FabB)，重组菌中主要不饱和脂肪酸的顺式疫苗(18：1 Delta 11)比例达到51.1%。当这两个基因共表达拟南芥硫代酯酶(AtFatA)时，该菌株在摇瓶条件下培养18h，可产生0.19mmolL(-1)脂肪酸。在该工程菌中，游离脂肪酸约占总脂肪酸的37.5%，UFA/SFA的比例达到2.3：1。该方法为改善微型柴油的脂肪酸组成提供了一种途径，并为在不久的将来利用工程微生物生产生物柴油替代品奠定了基础。
Biodiesel is an interesting alternative energy source and is used as substitute for petroleum-based diesel. Microorganisms have been used for biodiesel production due to their significant environmental and economic benefits. However, few researches have investigated the regulation of fatty acid composition of these microbial diesels. Fatty acid biosynthesis in Escherichia coli has provided a paradigm for other bacteria and plants. By overexpressing two genes (fabA and fabB) associated with unsaturated fatty acid (UFA) synthesis in E. coli, we have engineered an efficient producer of UFAs. Saturated fatty acid (SFA) contents decreased from 50.2% (the control strain) to 34.6% (the recombinant strain overexpressing fabA and fabB simultaneously) and the ratio of cis-vaccenate (18:1 Delta 11), a major UFA in E. coli, reached 51.1% in this recombinant strain. When an Arabidopsis thaliana thioesterase (AtFatA) was coexpressed with these two genes, 0.19 mmol l(-1) fatty acids was produced by this E. coli strain after 18-h culture under shake-flask conditions. Free fatty acids made up about 37.5% of total fatty acid concentration in this final engineered strain carrying fabA, fabB, and AtFatA, and the ratio of UFA/SFA reached 2.3:1. This approach offers a means to improve the fatty acid composition of microdiesel and might pave the way for production of biodiesel equivalents using engineered microorganisms in the near future.