title: Improved production of propionic acid in Propionibacterium jensenii via combinational overexpression of glycerol dehydrogenase and malate dehydrogenase from Klebsiella pneumoniae.
abstract: Microbial production of propionic acid (PA), an important chemical building block used as a preservative and chemical intermediate, has gained increasing attention for its environmental friendliness over traditional petrochemical processes. In previous studies, we constructed a shuttle vector as a useful tool for engineering Propionibacterium jensenii, a potential candidate for efficient PA synthesis. In this study, we identified the key metabolites for PA synthesis in P. jensenii by examining the influence of metabolic intermediate addition on PA synthesis with glycerol as a carbon source under anaerobic conditions. We also further improved PA production via the overexpression of the identified corresponding enzymes, namely, glycerol dehydrogenase (GDH), malate dehydrogenase (MDH), and fumarate hydratase (FUM). Compared to those in wild-type P. jensenii, the activities of these enzymes in the engineered strains were 2.91- ± 0.17- to 8.12- ± 0.37-fold higher. The transcription levels of the corresponding enzymes in the engineered strains were 2.85- ± 0.19- to 8.07- ± 0.63-fold higher than those in the wild type. The coexpression of GDH and MDH increased the PA titer from 26.95 ± 1.21 g/liter in wild-type P. jensenii to 39.43 ± 1.90 g/liter in the engineered strains. This study identified the key metabolic nodes limiting PA overproduction in P. jensenii and further improved PA titers via the coexpression of GDH and MDH, making the engineered P. jensenii strain a potential industrial producer of PA.
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhuge
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: Hyun-Dong
authors.initials: HD
authors.lastname: Shin
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia, USA.
authors.forename: Rachel R
authors.initials: RR
authors.lastname: Chen
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China.
authors.forename: Jianghua
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, China gcdu@jiangnan.edu.cn jchen@jiangnan.edu.cn.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.affiliation: National Engineering of Laboratory for Cereal Fermentation Technology, Jiangnan University, Wuxi, China gcdu@jiangnan.edu.cn jchen@jiangnan.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D000693:Anaerobiosis; D002244:Carbon / Q000378:metabolism; D005649:Fumarate Hydratase / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D005822:Genetic Vectors; D005990:Glycerol / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D008291:Malate Dehydrogenase / Q000235:genetics / Q000378:metabolism*; D060847:Metabolic Engineering; D011422:Propionates / Q000378:metabolism*; D011424:Propionibacterium / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D013401:Sugar Alcohol Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D011422:Propionates; D011994:Recombinant Proteins; D002244:Carbon; D013401:Sugar Alcohol Dehydrogenases; D008291:Malate Dehydrogenase; C020672:glycerol dehydrogenase; D005649:Fumarate Hydratase; C029658:propionic acid; D005990:Glycerol