Metabolic perturbation of acrylate pathway in Lactobacillus plantarum

Abstract

Engineering microbes with heterologous pathway for production of bio-based products has received considerable attention. Reconstituting such non-native pathway in addition to desired product formation often brings an allosteric modulation in enzymes competing at fragile nodes that result in by-product redistribution, in order to retain energy and redox balance. This work, Lactobacillus plantarum engineered with acrylate pathway for propionate production was studied under similar perspectives. Upon expression, the heterologous pathway did not result in propionic acid production under standard glucose concentration of 20 g/L, but 0.01 mM of propionate was formed when grown under low glucose concentration of 1 g/L. Further analysis of secreted metabolites with increased glucose concentration of 10 and 30 g/L remained futile towards propionate formation but showed reorientation in pyruvate metabolism which was related to the control imposed by the host to regulate the hidden constraints caused by gene perturbation. Further, it was ensured that the limitation of supplements did not play any functional role in inhibiting propionic acid synthesis but still followed similar metabolic pattern which was quite unclear though interpreted to certain extent. Thus, the findings gave insights into physiological and metabolic capabilities of Lactobacillus plantarum that at least in principle can be used to enhance the strain performance for increased propionic acid production.

Keywords:

• Acrylate pathway
• Lactobacillus plantarum
• metabolic engineering
• metabolic perturbation

Acknowledgements

The authors gratefully acknowledge Prof. Michiel Kleerebezem, Wageningen University & Research, NIZO Food Research, The Netherlands, for providing the bacterial strain Lactobacillus plantarum NZ7100. We also thank Department of Biotechnology, India for funding part of this research. The first author would like to thank University Grant Commission, India for providing fellowship through UGC-BSR scheme.

Disclosure statement

The authors declare that they have no conflict of interest.