Directed evolution of the 3-hydroxypropionic acid production pathway by engineering aldehyde dehydrogenase using a synthetic selection device

• Published in: Metabolic engineering 2018-05, Vol.47, p.113-120
• Main Authors: Seok, Joo Yeon, Yang, Jina, Choi, Sang Jin, Lim, Hyun Gyu, Choi, Un Jong, Kim, Kyung-Jin, Park, Sunghoon, Yoo, Tae Hyeon, Jung, Gyoo Yeol
• Format: Article
• Language: English
• Subjects: 3-hydroxypropionic acid; Aldehyde Dehydrogenase - genetics; Aldehyde Dehydrogenase - metabolism; Directed evolution; Directed Molecular Evolution; Escherichia coli - genetics; Escherichia coli - metabolism; Escherichia coli Proteins - genetics; Escherichia coli Proteins - metabolism; Lactic Acid - analogs & derivatives; Lactic Acid - biosynthesis; Metabolic engineering; Screening; Synthetic biology; Transcription factor
• ISSN: 1096-7176; 1096-7184
• DOI: 10.1016/j.ymben.2018.03.009

3-Hydroxypropionic acid (3-HP) is an important platform chemical, and biological production of 3-HP from glycerol as a carbon source using glycerol dehydratase (GDHt) and aldehyde dehydrogenase (ALDH) has been revealed to be effective because it involves a relatively simple metabolic pathway and exhibits higher yield and productivity than other biosynthetic pathways. Despite the successful attempts of 3-HP production from glycerol, the biological process suffers from problems arising from low activity and inactivation of the two enzymes. To apply the directed evolutionary approach to engineer the 3-HP production system, we constructed a synthetic selection device using a 3-HP-responsive transcription factor and developed a selection approach for screening 3-HP-producing microorganisms. The method was applied to an ALDH library, specifically aldehyde-binding site library of alpha-ketoglutaric semialdehyde dehydrogenase (KGSADH). Only two serial cultures resulted in enrichment of strains showing increased 3-HP production, and an isolated KGSADH variant enzyme exhibited a 2.79-fold higher catalytic efficiency toward its aldehyde substrate than the wild-type one. This approach will provide the simple and efficient tool to engineer the pathway enzymes in metabolic engineering. •A synthetic selection device was designed responding to 3-HP concentration.•ALDH in the 3-HP pathway was engineered through a simple selection method.•An ALDH variant exhibited a 2.79-fold improvement in the catalytic efficiency.•E. coli with ALDH variant showed a 25% higher productivity than the parental strain.•The developed strategy was highly efficient for engineering the pathway enzymes.