Anoxic metabolism and biochemical production in Pseudomonas putida F1 driven by a bioelectrochemical system

Lai, Bin, Yu, Shiqin, Bernhardt, Paul V., Rabaey, Korneel, Virdis, Bernadino and Krömer, Jens O. (2016) Anoxic metabolism and biochemical production in Pseudomonas putida F1 driven by a bioelectrochemical system. Biotechnology for Biofuels, 9 39.1-39.13. doi:10.1186/s13068-016-0452-y


Author Lai, Bin
Yu, Shiqin
Bernhardt, Paul V.
Rabaey, Korneel
Virdis, Bernadino
Krömer, Jens O.
Title Anoxic metabolism and biochemical production in Pseudomonas putida F1 driven by a bioelectrochemical system
Formatted title
Anoxic metabolism and biochemical production in Pseudomonas putida F1 driven by a bioelectrochemical system
Journal name Biotechnology for Biofuels   Check publisher's open access policy
ISSN 1754-6834
Publication date 2016-02-18
Sub-type Article (original research)
DOI 10.1186/s13068-016-0452-y
Open Access Status DOI
Volume 9
Start page 39.1
End page 39.13
Total pages 13
Place of publication London, United Kingdom
Publisher BioMed Central
Language eng
Formatted abstract
Background: Pseudomonas putida is a promising host for the bioproduction of chemicals, but its industrial applications are significantly limited by its obligate aerobic character. The aim of this paper is to empower the anoxic metabolism of wild-type Pseudomonas putida to enable bioproduction anaerobically, with the redox power from a bioelectrochemical system (BES).

Results: The obligate aerobe Pseudomonas putida F1 was able to survive and produce almost exclusively 2-Keto-gluconate from glucose under anoxic conditions due to redox balancing with electron mediators in a BES. 2-Keto-gluconate, a precursor for industrial anti-oxidant production, was produced at an overall carbon yield of over 90 % based on glucose. Seven different mediator compounds were tested, and only those with redox potential above 0.207 V (vs standard hydrogen electrode) showed interaction with the cells. The productivity increased with the increasing redox potential of the mediator, indicating this was a key factor affecting the anoxic production process. P. putida cells survived under anaerobic conditions, and limited biofilm formation could be observed on the anode's surface. Analysis of the intracellular pools of ATP, ADP and AMP showed that cells had an increased adenylate energy charge suggesting that cells were able to generate energy using the anode as terminal electron acceptor. The analysis of NAD(H) and NADP(H) showed that in the presence of specific extracellular electron acceptors, the NADP(H) pool was more oxidised, while the NAD(H) pool was unchanged. This implies a growth limitation under anaerobic conditions due to a shortage of NADPH and provides a way to limit biomass formation, while allowing cell maintenance and catalysis at high purity and yield.

Conclusions: For the first time, this study proved the principle that a BES-driven bioconversion of glucose can be achieved for a wild-type obligate aerobe. This non-growth bioconversion was in high yields, high purity and also could deliver the necessary metabolic energy for cell maintenance. By combining this approach with metabolic engineering strategies, this could prove to be a powerful new way to produce bio-chemicals and fuels from renewables in both high yield and high purity.
Keyword Anoxic metabolism
Bio-production
Bioelectrochemical system
Chemical feedstocks
Extracellular electron transfer
Pseudomonas putida F1
Redox mediators
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
School of Chemistry and Molecular Biosciences
Advanced Water Management Centre Publications
 
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Created: Fri, 26 Feb 2016, 20:58:36 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences