Enhanced sucrose fermentation by introduction of heterologous sucrose transporter and invertase into Clostridium beijerinckii for acetone-butanol-ethanol production.

Liqin Du,Yi Liu,Lihua Lin,Hongchi Tang,Ribo Huang,Yuan Guo,Hao Pang,Bingqing Zhou,Zhikai Zhang

doi:10.1098/rsos.201858

Abstract

A heterologous pathway for sucrose transport and metabolism was introduced into Clostridium beijerinckii to improve sucrose use for n-butanol production. The combined expression of StSUT1, encoding a sucrose transporter from potato (Solanum tuberosum), and SUC2, encoding a sucrose invertase from Saccharomyces cerevisiae, remarkably enhanced n-butanol production. With sucrose, sugarcane molasses and sugarcane juice as substrates, the C. beijerinckii strain harbouring StSUT1 and SUC2 increased acetone–butanol–ethanol production by 38.7%, 22.3% and 52.8%, respectively, compared with the wild-type strain. This is the first report to demonstrate enhanced sucrose fermentation due to the heterologous expression of a sucrose transporter and invertase in Clostridium. The metabolic engineering strategy used in this study can be widely applied in other microorganisms to enhance the production of high-value compounds from sucrose-based biomass.

Highlights

Introduction nButanol is a valuable chemical used as a solvent and intermediate in a variety of industries [1,2], and is an advanced biofuel alternative to fossil fuels [3,4]
High transport activity of StSUT1 was observed in both the acidogenesis and solventogenesis phases. These data suggest that StSUT1 induces efficient sucrose transport in C. beijerinckii
The control strain CB1341 exhibited weak fluorescence in the assay, indicating that the native sucrose transport system (PTS) of C. beijerinckii takes up some esculin

Summary

Introduction

Introduction nButanol is a valuable chemical used as a solvent and intermediate in a variety of industries [1,2], and is an advanced biofuel alternative to fossil fuels [3,4]. With increasing product demand and environmental consciousness, fermentative methods of n-butanol production have gained popularity in recent years. Many factors limit the capacity of wild-type Clostridium strains for butanol production, including low substrate conversion rate, low solvent tolerance, low cell biomass, and excessive byproduct production [10,11,12]. To overcome these problems, various metabolic engineering strategies have been applied to increase n-butanol production in different host strains [11,13,14,15]

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Conclusion