Metabolic engineered E. coli for the production of (R)-1,2-propanediol from biodiesel derived glycerol

Abstract

The development of the biodiesel industry with the concomitant production of glycerol as the major byproduct has had a negative impact on the glycerol market. The application of circular economy concepts has led to progress in production processes that use this residue as starting material. Propylene glycol has been identified as a potential destiny of glycerol surplus; however, the possibility of increasing this valorization from the existence of a stereogenic center has been scarcely explored. Using metabolic engineering in E. coli, a set of biocatalysts capable of biotransforming glycerol to (R)-1,2-propanediol has been designed, built, and evaluated. The simultaneous expression of a methylglyoxal reductase (Gre2p) and an aldehyde reductase (Ypr1p) both from S. cerevisiae origin, along with the overexpression of E. coli methylglyoxal synthase (mgsA), resulted in an E. coli strain capable of producing enantiomerically pure (e.e.> 99%) (R)-1,2-propanediol from glycerol, in a concentration of 209 ± 9 mg.L^-1. The developed biocatalysts presented a satisfactory performance when crude glycerin obtained from biodiesel production process was used in place of glycerol.

Keywords:

• Biodiesel
• glycerol
• metabolic engineering
• (R)-1,2-propanediol
• green chemistry

Acknowledgments

The authors wish to thank MSc Julio Battistoni for establishing the relevance of this topic addressed in the local context, Dr. Tung T. Hoang for donating strain E. coli(HPS1-mob-Δasd-pir116) and plasmid pBT20ΔblaT7pol, and ALUR (Alcoholes del Uruguay S.A.) for providing glycerine samples obtained from industrial processes.

Disclosure statement

No potential conflict of interest was reported by the authors.

Availability of data and material

All data and material that support conclusions of the present paper are available. It should be considered that part of this research is included in a patent application that is being analyzed by the agency that regulates industrial property at the local level.

Authors' contributions

SRG and PM made substantial contributions to the conception and design of the research.

WS was mostly involved in assays execution. However, all authors were involved in the acquisition, analysis and interpretation of data used in the work. All authors have been involved in manuscript preparation, critical revision, and approval of the final version to be published. All of them agree to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Additional information

Funding

The authors acknowledge funding from Programa de Desarrollo de las Ciencias Básicas (PEDECIBA), Instituto Nacional de Investigaciones Agrícolas Grant INIA-FPTA-2006 and Programa de Desarrollo Tecnológico Grant PDT-47/06. The intellectual property protection activities related to the present research were funded by Comisión Sectorial de Investigación Científica (CSIC-Udelar).