Research Progress in the Production of D-Lactic Acid from Renewable Resources

D-lactic acid is a key chiral intermediate widely applied in agriculture, pharmaceuticals, and polylactic acid synthesis, with microbial fermentation as its main production method. Commercial D-lactic acid production depends heavily on refined carbohydrates and yeast extract as carbon and nitrogen sources, resulting in prohibitive raw material costs. Abundant in microbially available proteins and carbohydrates, renewable resources can act as carbon and nitrogen substrates for efficient D-lactic acid production. Repurposing these resources reduces production expenses and is essential for the industrial scaling of D-lactic acid manufacturing. This paper reviews research advances in D-lactic acid fermentation using renewable feedstocks including agricultural wastes, sugar industry residues, oil processing wastes, and cheese processing by-products as carbon and nitrogen sources.