A Review of the Recent Developments in the Bioproduction of Polylactic Acid and Its Precursors Optically Pure Lactic Acids

Abstract

Lactic acid (LA) is an important organic acid with broad industrial applications. Considered as an environmentally friendly alternative to petroleum-based plastic with a wide range of applications, polylactic acid has generated a great deal of interest and therefore the demand for optically pure l- or d-lactic acid has increased accordingly. Microbial fermentation is the industrial route for LA production. LA bacteria and certain genetic engineering bacteria are widely used for LA production. Although some fungi, such as Saccharomyces cerevisiae, are not natural LA producers, they have recently received increased attention for LA production because of their acid tolerance. The main challenge for LA bioproduction is the high cost of substrates. The development of LA production from cost-effective biomasses is a potential solution to reduce the cost of LA production. This review examined and discussed recent progress in optically pure l-lactic acid and optically pure d-lactic acid fermentation. The utilization of inexpensive substrates is also focused on. Additionally, for PLA production, a complete biological process by one-step fermentation from renewable resources is also currently being developed by metabolically engineered bacteria. We also summarize the strategies and procedures for metabolically engineering microorganisms producing PLA. In addition, there exists some challenges to efficiently produce PLA, therefore strategies to overcome these challenges through metabolic engineering combined with enzyme engineering are also discussed.

An efficient CRISPR/Cas9‐based genome editing system for alkaliphilic Bacillus sp. N16‐5 and application in engineering xylose utilization for D‐lactic acid production

“…N16‐5 (Song et al, 2013 ), it will be a good choice to employ the xylose non‐phosphorylative metabolism pathway to enhance the xylose consumption rate to bypass the native sugar metabolism regulation (Bai et al, 2016 ; Cabulong et al, 2021 ; Choi et al, 2016 ; Tai et al, 2016 ). Currently, PLA production with a complete biological process by one‐step fermentation from renewable resources has been also developed by metabolically engineered bacteria (Huang et al, 2021 ). Depending on the CRISPR/Cas9 for an efficient genome modification and metabolic engineering, Bacillus sp.…”

Distribution and Quantification of Lactic Acid Enantiomers in Baijiu

“…So far, the formation pathway of lactic acid enantiomers in Baijiu has not been clarified. Many microorganisms have been reported to have the ability to produce L-lactic acid, such as Lactobacillus , Bacillus coagulans , and various transgenic strains [ 32 ]. Lactic acid is an important metabolite produced by lactic acid bacteria during fermentation, and high levels of lactic acid may lead to rancidity [ 33 ].…”

A highly stable bio-based plasticizer constructed from renewable acids for plasticizing and enhancing the optical properties of poly(vinyl chloride)

“…38 Lactic acid contains carboxyl and hydroxyl groups and can be utilized as a starting material for the synthesis of various chemicals, and its most generally utilized application is the production of high value-added chemicals, for example, degradable polymers. 39 Under specific circumstances, lactic acid can self-polymerize to form lactic acid oligomers with rich polar groups. Therefore, the plasticizer prepared by the self-polymerization of lactic acid has a large number of polar groups (ester groups).…”