Mechanisms underlying lactic acid tolerance and its influence on lactic acid production in Saccharomyces cerevisiae.

Arne Peetermans,María R Foulquié-Moreno,Johan M Thevelein

doi:10.15698/mic2021.06.751

Abstract

One of the major bottlenecks in lactic acid production using microbial fermentation is the detrimental influence lactic acid accumulation poses on the lactic acid producing cells. The accumulation of lactic acid results in many negative effects on the cell such as intracellular acidification, anion accumulation, membrane perturbation, disturbed amino acid trafficking, increased turgor pressure, ATP depletion, ROS accumulation, metabolic dysregulation and metal chelation. In this review, the manner in which Saccharomyces cerevisiae deals with these issues will be discussed extensively not only for lactic acid as a singular stress factor but also in combination with other stresses. In addition, different methods to improve lactic acid tolerance in S. cerevisiae using targeted and non-targeted engineering methods will be discussed.

Highlights

The compound lactic acid is a molecule with a long history of use in the food industry as a preservative, pH buffering agent, flavoring agent and acidulant [1]
Upon glucose depletion more lactic acid was consumed in the strain expressing ADY2 [59]. These results suggest that the transport of lactate by Ady2 is bidirectional and that ADY2 can be modified to increase lactic acid production in S. cerevisiae in glucose medium
Alternative export mechanisms of lactate in S. cerevisiae upon lactic acid stress It has been shown that the deletion of both ADY2 and JEN1 decreases extracellular lactic acid production in a lactic acid producing heterolactic S. cerevisiae strain both in xylose and glucose media

Summary

Introduction

The compound lactic acid is a molecule with a long history of use in the food industry as a preservative, pH buffering agent, flavoring agent and acidulant [1]. Targeting of the mechanisms responsible for coping with lactic acid stress has shown to be effective in increasing the titers, productivity and yield of lactic acid producing S. cerevisiae strains.

Results

Conclusion