title: Very high gravity ethanol and fatty acid production of Zymomonas mobilis without amino acid and vitamin.
abstract: Very high gravity (VHG) fermentation is the mainstream technology in ethanol industry, which requires the strains be resistant to multiple stresses such as high glucose concentration, high ethanol concentration, high temperature and harsh acidic conditions. To our knowledge, it was not reported previously that any ethanol-producing microbe showed a high performance in VHG fermentations without amino acid and vitamin. Here we demonstrate the engineering of a xylose utilizing recombinant Zymomonas mobilis for VHG ethanol fermentations. The recombinant strain can produce ethanol up to 136 g/L without amino acid and vitamin with a theoretical yield of 90 %, which is significantly superior to that produced by all the reported ethanol-producing strains. The intracellular fatty acids of the bacterial were about 16 % of the bacterial dry biomass, with the ratio of ethanol:fatty acids was about 273:1 (g/g). The recombinant strain was achieved by a multivariate-modular strategy tackles with the multiple stresses which are closely linked to the ethanol productivity of Z. mobilis. The over-expression of metB/yfdZ operon enabled the growth of the recombinant Z. mobilis in a chemically defined medium without amino acid and vitamin; and the fatty acids overproduction significantly increased ethanol tolerance and ethanol production. The coupled production of ethanol with fatty acids of the Z. mobilis without amino acid and vitamin under VHG fermentation conditions may permit a significant reduction of the production cost of ethanol and microbial fatty acids.
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Key Laboratory of Industrial Microbiology, College of Bioengineering, Hubei University of Technology, Wuhan, 430068, China. haoyongw@163.com.
authors.forename: Haoyong
authors.initials: H
authors.lastname: Wang
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Key Laboratory of Industrial Microbiology, College of Bioengineering, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Shangzhi
authors.initials: S
authors.lastname: Cao
authors.affiliation: Wuluolu Middle School, Wuhan, 430071, China.
authors.forename: William Tianshuo
authors.initials: WT
authors.lastname: Wang
authors.affiliation: Zhichunli Middle School, Beijing, 100086, China.
authors.forename: Kaven Tianyv
authors.initials: KT
authors.lastname: Wang
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Key Laboratory of Industrial Microbiology, College of Bioengineering, Hubei University of Technology, Wuhan, 430068, China. 455301269@qq.com.
authors.forename: Xianhui
authors.initials: X
authors.lastname: Jia
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics; D000431:Ethanol / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis*; D005285:Fermentation; D005947:Glucose / Q000737:chemistry; D006358:Hot Temperature; D007218:Industrial Microbiology; D060847:Metabolic Engineering; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014815:Vitamins / Q000737:chemistry; D014994:Xylose / Q000737:chemistry; D017355:Zymomonas / Q000235:genetics / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D001426:Bacterial Proteins; D003470:Culture Media; D004269:DNA, Bacterial; D005227:Fatty Acids; D011994:Recombinant Proteins; D014815:Vitamins; D000431:Ethanol; D014994:Xylose; D005947:Glucose
keywords: Ethanol; Microbial fatty acid; Very high gravity fermentation; Zymomonas mobilis