Enhanced D-lactic acid production from renewable resources using engineered Lactobacillus plantarum

• Published in: Applied microbiology and biotechnology Vol. 100; no. 1; pp. 279 - 288
• Main Authors: Zhang, Yixing, Vadlani, Praveen V, Kumar, Amit, Hardwidge, Philip R, Govind, Revathi, Tanaka, Tsutomu, Kondo, Akihiko
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.01.2016; Springer Nature B.V
• Subjects: Acid production; Acids; Aldose-Ketose Isomerases - genetics; Aldose-Ketose Isomerases - metabolism; Alternative energy sources; Amino acids; Applied Genetics and Molecular Biotechnology; Bacteria; Batch Cell Culture Techniques; batch fermentation; biodegradability; Biodegradation; Biomass; Biomedical and Life Sciences; Bioplastics; Biotechnology; Biotransformation; Corn; corn stover; cost effectiveness; Culture Media - chemistry; Dehydrogenases; E coli; Ethanol; Fermentation; Gene expression; Genes; Genetic engineering; glucose; Glucose - metabolism; Glycine max - metabolism; Lactic Acid - metabolism; Lactobacillus plantarum; Lactobacillus plantarum - genetics; Lactobacillus plantarum - metabolism; Life Sciences; Metabolic Engineering - methods; Microbial Genetics and Genomics; Microbiology; Microorganisms; Peptones; Phosphotransferases (Alcohol Group Acceptor) - genetics; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Plasmids; plastics; Polylactic acid; Renewable resources; response surface methodology; soybean meal; Soybeans; Stover; Studies; Sugar; thermal stability; xylose; Xylose - metabolism; xylose isomerase; Yeast; Zea mays - metabolism; United States > US; Xylose fermentation; Corn Stover; Lactic acid; Response surface methodology; Lactobacillus plantarum
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-015-7016-0

D-lactic acid is used as a monomer in the production of poly-D-lactic acid (PDLA), which is used to form heat-resistant stereocomplex poly-lactic acid. To produce cost-effective D-lactic acid by using all sugars derived from biomass efficiently, xylose-assimilating genes encoding xylose isomerase and xylulokinase were cloned into an L-lactate-deficient strain, Lactobacillus plantarum. The resulting recombinant strain, namely L. plantarum NCIMB 8826 ∆ldhL1-pLEM-xylAB, was able to produce D-lactic acid (at optical purity >99 %) from xylose at a yield of 0.53 g g⁻¹. Simultaneous utilization of glucose and xylose to produce D-lactic acid was also achieved by this strain, and 47.2 g L⁻¹ of D-lactic acid was produced from 37.5 g L⁻¹ glucose and 19.7 g L⁻¹ xylose. Corn stover and soybean meal extract (SBME) were evaluated as cost-effective medium components for D-lactic acid production. Optimization of medium composition using response surface methodology resulted in 30 % reduction in enzyme loading and 70 % reduction in peptone concentration. In addition, we successfully demonstrated D-lactic acid fermentation from corn stover and SBME in a fed-batch fermentation, which yielded 61.4 g L⁻¹ D-lactic acid with an overall yield of 0.77 g g⁻¹. All these approaches are geared to attaining high D-lactic acid production from biomass sugars to produce low-cost, highly thermostable biodegradable plastics.