Improved phloroglucinol production by metabolically engineered Escherichia coli
Improved phloroglucinol production by metabolically engineered Escherichia coli
复制标题
通过代谢工程大肠杆菌提高间苯三酚产量
DOI：
10.1007/s00253-011-3304-5
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发表时间：
2011-09-01
影响因子：
5
通讯作者：
Xian, Mo
中科院分区：
文献类型：
--
作者：
Cao, Yujin;Jiang, Xinglin;Xian, Mo
间苯三酚是一种有价值的化学品，已通过代谢工程大肠杆菌成功生产。然而，生产率低下仍然是大规模应用和经济高效生产的瓶颈。在目前的工作中，我们将关键的生物合成基因phlD（一种III型聚酮合酶）克隆到细菌表达载体中，以在大肠杆菌中生产间苯三酚，并开发了不同的策略来重新设计重组菌株，以实现间苯三酚的稳健合成。大肠杆菌 marA（多重抗生素耐药性）基因的过度表达增强了间苯三酚耐药性，并将间苯三酚产量提高至 0.27 g/g 细胞干重。通过四个乙酰辅酶 A 羧化酶 (ACCase) 亚基的协调表达来提高细胞内丙二酰辅酶 A (丙二酰辅酶 A) 水平，从而将间苯三酚产量增加至约 0.27 g/g 细胞干重。此外，ACCase和marA的共表达导致间苯三酚产量再次显着提高，达到0.45 g/g细胞干重，即原始菌株的3.3倍。在分批补料条件下，该最终工程菌株在诱导后 12 小时在培养物中累积间苯三酚高达 3.8 g/L，相当于 0.32 g/L/h 的体积生产率。这一结果是迄今为止最高的间苯三酚产量，并表明该生物工艺有望在经济上可行。
Phloroglucinol is a valuable chemical which has been successfully produced by metabolically engineered Escherichia coli. However, the low productivity remains a bottleneck for large-scale application and cost-effective production. In the present work, we cloned the key biosynthetic gene, phlD (a type III polyketide synthase), into a bacterial expression vector to produce phloroglucinol in E. coli and developed different strategies to re-engineer the recombinant strain for robust synthesis of phloroglucinol. Overexpression of E. coli marA (multiple antibiotic resistance) gene enhanced phloroglucinol resistance and elevated phloroglucinol production to 0.27 g/g dry cell weight. Augmentation of the intracellular malonyl coenzyme A (malonyl-CoA) level through coordinated expression of four acetyl-CoA carboxylase (ACCase) subunits increased phloroglucinol production to around 0.27 g/g dry cell weight. Furthermore, the coexpression of ACCase and marA caused another marked improvement in phloroglucinol production 0.45 g/g dry cell weight, that is, 3.3-fold to the original strain. Under fed-batch conditions, this finally engineered strain accumulated phloroglucinol up to 3.8 g/L in the culture 12 h after induction, corresponding to a volumetric productivity of 0.32 g/L/h. This result was the highest phloroglucinol production to date and showed promising to make the bioprocess economically feasible.