Genetic Engineering of Microbial Strains for High-Yield Lactic Acid Production

Abstract

Lactic acid (LA) is an organic acid with broad applications across food, pharmaceutical, cosmetic, and biodegradable polymer industries—most notably polylactic acid (PLA). Conventional production relying on wild-type lactic acid bacteria (LAB) often suffers from limited yield, substrate specificity, and by-product formation. Genetic engineering provides powerful tools to develop robust microbial strains capable of high-yield, low-cost, and optically pure lactic acid production from diverse feedstocks. This paper extensively reviews strategies in genetic and metabolic engineering for enhanced lactic acid synthesis, covering genome editing techniques, pathway optimizations, adaptive laboratory evolution, heterologous pathway construction, and systems biology. Challenges, industrial case studies, and future directions including synthetic biology and CRISPR-based regulation are discussed. The goal is to synthesize current knowledge and highlight promising avenues for improving industrial LA production.