title: Enhanced D-lactic acid production from renewable resources using engineered Lactobacillus plantarum.
abstract: 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.
authors.affiliation: Bioprocessing and Renewable Energy Laboratory, Department of Grain Science and Industry, Kansas State University, Manhattan, KS, USA. essie@ksu.edu.
authors.forename: Yixing
authors.identifier: http://orcid.org/0000-0002-1084-4237
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Bioprocessing and Renewable Energy Laboratory, Department of Grain Science and Industry, Kansas State University, Manhattan, KS, USA.|Department of Chemical Engineering, Kansas State University, Manhattan, KS, USA.
authors.forename: Praveen V
authors.initials: PV
authors.lastname: Vadlani
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
authors.forename: Amit
authors.initials: A
authors.lastname: Kumar
authors.affiliation: Department of Diagnostic Medicine and Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA.
authors.forename: Philip R
authors.initials: PR
authors.lastname: Hardwidge
authors.affiliation: Division of Biology, Kansas State University, Manhattan, KS, USA.
authors.forename: Revathi
authors.initials: R
authors.lastname: Govind
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe, 657-8501, Japan.
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tanaka
authors.affiliation: Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, 1-1 Rokkodaicho, Nada, Kobe, 657-8501, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kondo
mesh_terms: D019747:Aldose-Ketose Isomerases / Q000235:genetics / Q000378:metabolism; D061249:Batch Cell Culture Techniques; D018533:Biomass; D001711:Biotransformation; D003470:Culture Media / Q000737:chemistry; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism*; D048191:Lactiplantibacillus plantarum / Q000235:genetics* / Q000378:metabolism*; D060847:Metabolic Engineering / Q000379:methods*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D013025:Glycine max / Q000378:metabolism; D014994:Xylose / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism
chemical_list: D003470:Culture Media; D019344:Lactic Acid; D014994:Xylose; D017853:Phosphotransferases (Alcohol Group Acceptor); C032700:xylulokinase; D019747:Aldose-Ketose Isomerases; C023298:xylose isomerase; D005947:Glucose
keywords: Corn Stover; Lactic acid; Lactobacillus plantarum; Response surface methodology; Xylose fermentation