Succinic Acid Production by Engineered <i>Mannheimia succiniciproducens</i> and Its Use in Chemoenzymatic Poly(Butylene Succinate) Synthesis

Amid growing concerns about climate change, environmental pollution, and fossil resource depletion, bio-based chemicals and materials have garnered significant attention. Succinic acid (SA), a four-carbon dicarboxylic acid, is a key platform chemical for producing industrially important compounds such as poly(butylene succinate) (PBS), a biodegradable polymer. In this paper, we demonstrate the enhanced production of SA using metabolically engineered Mannheimia succiniciproducens PALK (pMS3-gltA) strain, which achieves high SA yields through enhanced biomass production and optimized metabolic pathways. High-purity SA, purified from the fermentation broth, was used in an environmentally friendly two-step polymerization process under mild conditions. In the first step, diethyl succinate was synthesized from SA and ethanol using Amberlyst as a catalyst. This was followed by polymerization with 1,4-butanediol, catalyzed by Candida antarctica lipase B. The resulting PBS exhibited comparable thermal stability and molecular weight distribution to its petrochemical counterpart, with enhanced biodegradability. By integrating metabolic engineering with sustainable polymer synthesis, this study underscores the potential for an eco-friendly approach to developing bio-based polymers, offering a promising solution to the environmental challenges posed by conventional plastics.