Improved bioethanol production using genome-shuffled Clostridium ragsdalei (DSM 15248) strains through syngas fermentation

ABSTRACT

In the present study, a genome shuffling approach was used for improvement of ethanol and acetic acid tolerance of C. ragsdalei (DSM 15248). Evaluation of metabolite production from selected shuffled strains was also conducted. Random mutagenesis was carried out using ethyl-methyl-sulfonate and UV followed by protoplast fusion. Promising fusants were selected based on enhanced ethanol and acetic acid tolerance and further evaluated for metabolite production through syngas fermentation. Strain F3-A obtained after the third round of shuffling showed ethanol production of 14.92 ± 0.75 g/L, while the parent strain showed ethanol production of 1.92 ± 0.52 g/L after seven days of syngas fermentation at 37 °C. Enhancement in 1-butanol production was also observed in shuffled strain F3-A. A seven-fold increase in ethanol concentration for shuffled strain F3-A was obtained. The study confirms the successful implementation of the genome shuffling technique for significant enhancement of metabolite production using syngas fermentation.

KEYWORDS:

• Syngas fermentation
• genome shuffling
• random mutagenesis
• bioethanol
• protoplast fusion

Acknowledgement

The authors would like to acknowledge the Sugar Development Fund, Government of India, for the financial support provided for this study. They would also like to thank the analytical chemists in the Department of Alcohol Technology, Vasantdada Sugar Institute, for assistance in analysis of the samples.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Sugar Development Fund, Government of India and the Department of Food and Public Distribution, Directorate of Sugar, GOI [grant number 6-6/2011-SDF/DCS, 8 April 2013].