Metabolic engineering of Escherichia coli to enhance hydrogen production from glycerol
Metabolic engineering of Escherichia coli to enhance hydrogen production from glycerol
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DOI：
10.1007/s00253-014-5600-3
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发表时间：
2014-05-01
影响因子：
5
通讯作者：
Wood, Thomas K.
中科院分区：
文献类型：
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作者：
Kien Trung Tran;Maeda, Toshinari;Wood, Thomas K.
甘油对于生物燃料生产来说是一种有吸引力的碳源，因为由于对可再生和清洁能源（包括生物柴油的生产）的需求不断增加，甘油价格便宜且丰富。这项研究旨在通过定向删除来操纵大肠杆菌的代谢途径，从而提高大肠杆菌从甘油中产生氢气的能力。由于我们过去的菌株是为从葡萄糖生产氢气而设计的，不适合从甘油生产氢气，因此我们重新筛选了与氢气生产和甘油代谢相关的14个基因。我们发现10个单基因敲除有利于增强甘油的产氢，即frdC（编码富马酸还原酶）、ldhA（乳酸脱氢酶）、fdnG（甲酸脱氢酶）、ppc（磷酸烯醇丙酮酸羧化酶）、narG（硝酸还原酶）、focA（甲酸转运蛋白）、hyaB（氢化酶1的大亚基）、aceE （丙酮酸脱氢酶）、mgsA（甲基乙二醛合酶）和 hycA（转录调节因子 FhlA 的调节因子）。在此基础上，我们通过连续的 P1 转导创建了多个敲除菌株。同时敲除frdC、ldhA、fdnG、ppc、narG、mgsA和hycA创建了最好的菌株，其产生的氢气量比亲本菌株高5倍，并且氢气产率高5倍。 48小时后，工程菌株还达到了1 mol H-2/mol甘油的理论最大产量。在低分压发酵下，菌株的生长速度加快了两倍以上，表明甘油的利用和氢气的产生更快。通过将代谢工程和低分压发酵相结合，甘油的氢气产量显着提高。
Glycerol is an attractive carbon source for biofuel production since it is cheap and abundant due to the increasing demand for renewable and clean energy sources, which includes production of biodiesel. This research aims to enhance hydrogen production by Escherichia coli from glycerol by manipulating its metabolic pathways via targeted deletions. Since our past strain, which had been engineered for producing hydrogen from glucose, was not suitable for producing hydrogen from glycerol, we rescreened 14 genes related to hydrogen production and glycerol metabolism. We found that 10 single knockouts are beneficial for enhanced hydrogen production from glycerol, namely, frdC (encoding for furmarate reductase), ldhA (lactate dehydrogenase), fdnG (formate dehydrogenase), ppc (phosphoenolpyruvate carboxylase), narG (nitrate reductase), focA (formate transporter), hyaB (the large subunit of hydrogenase 1), aceE (pyruvate dehydrogenase), mgsA (methylglyoxal synthase), and hycA (a regulator of the transcriptional regulator FhlA). On that basis, we created multiple knockout strains via successive P1 transductions. Simultaneous knockouts of frdC, ldhA, fdnG, ppc, narG, mgsA, and hycA created the best strain that produced 5-fold higher hydrogen and had a 5-fold higher hydrogen yield than the parent strain. The engineered strain also reached the theoretical maximum yield of 1 mol H-2/mol glycerol after 48 h. Under low partial pressure fermentation, the strain grew over 2-fold faster, indicating faster utilization of glycerol and production of hydrogen. By combining metabolic engineering and low partial pressure fermentation, hydrogen production from glycerol was enhanced significantly.