Microbial tolerance engineering for boosting lactic acid production from lignocellulose

Abstract

Lignocellulosic biomass is an attractive non-food feedstock for lactic acid production via microbial conversion due to its abundance and low-price, which can alleviate the conflict with food supplies. However, a variety of inhibitors derived from the biomass pretreatment processes repress microbial growth, decrease feedstock conversion efficiency and increase lactic acid production costs. Microbial tolerance engineering strategies accelerate the conversion of carbohydrates by improving microbial tolerance to toxic inhibitors using pretreated lignocellulose hydrolysate as a feedstock. This review presents the recent significant progress in microbial tolerance engineering to develop robust microbial cell factories with inhibitor tolerance and their application for cellulosic lactic acid production. Moreover, microbial tolerance engineering crosslinking other efficient breeding tools and novel approaches are also deeply discussed, aiming to providing a practical guide for economically viable production of cellulosic lactic acid.

Mid–Long Chain Dicarboxylic Acid Production via Systems Metabolic Engineering: Progress and Prospects

“…The first step of this process requires the degradation of lignocellulose into monosaccharides or aromatic compounds via enzymatic or chemical methods. This is followed by the use of different microbial metabolic pathways to produce lactic acid, 3-hydroxypropionic acid, succinic acid, fatty acids, DDA, and other products. − However, the formation of certain toxic intermediates during the pretreatment of lignocellulose affects the growth of microorganisms, reducing the conversion rate and increasing production costs. , Therefore, the development of efficient pretreatment processes to reduce the generation of toxic and harmful substances could alleviate the problem of resource depletion caused by the use of fossil fuel-derived materials such as alkanes for the production of long-chain DCAs. Further, it could also reduce the use of sugar-based carbon sources.…”

Biosensor-assisted CRISPRi high-throughput screening to identify genetic targets in Zymomonas mobilis for high d-lactate production

“…However, these lignocellulosic materials are difficult for microbial fermentation because different inhibitors were produced during pretreatment, enzymatic hydrolysis, and fermentation processes [ 6 ], such as furan derivatives, weak acids, and phenolic compounds [ 7 ]. These inhibitors could reduce microbial cell viability and increase production costs [ 8 ]. Therefore, it is crucial to explore and develop robust microbial cell factories for economic lignocellulosic lactate production.…”