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Small Current but Highly Productive Synthesis of 1,3‐Propanediol from Glycerol by an Electrode‐Driven Metabolic Shift in Klebsiella pneumoniae L17
Author(s) -
Kim Changman,
Lee Jae Hyeon,
Baek Jiyun,
Kong Da Seul,
Na JeongGeol,
Lee Jinwon,
Sundstrom Eric,
Park Sunghoon,
Kim Jung Rae
Publication year - 2020
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201902928
Subject(s) - glycerol , fermentation , 1,3 propanediol , chemistry , bioconversion , redox , metabolic engineering , biochemistry , inorganic chemistry , enzyme
Electrofermentation actively regulates the bacterial redox state, which is essential for bioconversion and has been highlighted as an effective method for further improvements of the productivity of either reduced or oxidized platform chemicals. 1,3‐Propanediol (1,3‐PDO) is an industrial value‐added chemical that can be produced from glycerol fermentation. The bioconversion of 1,3‐PDO from glycerol requires additional reducing energy under anoxic conditions. The cathode‐based conversion of glycerol to 1,3‐PDO with various electron shuttles (2‐hydroxy‐1,4‐naphthoquinone, neutral red, and hydroquinone) using Klebsiella pneumoniae L17 was investigated. The externally poised potential of −0.9 V vs. Ag/AgCl to the cathode increased 1,3‐PDO (35.5±3.1 m m ) production if 100 μ m neutral red was used compared with non‐bioelectrochemical system fermentation (23.7±2.4 m m ). Stoichiometric metabolic flux and transcriptional analysis indicated a shift in the carbon flux toward the glycerol reductive pathway. The homologous overexpression of glycerol dehydratase (DhaB) and 1,3‐PDO oxidoreductase (DhaT) enzymes synergistically enhanced 1,3‐PDO conversion (39.3±0.8 m m ) under cathode‐driven fermentation. Interestingly, a small current uptake (0.23 mmol of electrons) caused significant metabolic flux changes with a concomitant increase in 1,3‐PDO production. This suggests that both an increase in 1,3‐PDO production and regulation of the cellular metabolic pathway are feasible by electrode‐driven control in cathodic electrofermentation.