title: Synthesis of (3R)-acetoin and 2,3-butanediol isomers by metabolically engineered Lactococcus lactis.
abstract: The potential that lies in harnessing the chemical synthesis capabilities inherent in living organisms is immense. Here we demonstrate how the biosynthetic machinery of Lactococcus lactis, can be diverted to make (3R)-acetoin and the derived 2,3-butanediol isomers meso-(2,3)-butanediol (m-BDO) and (2R,3R)-butanediol (R-BDO). Efficient production of (3R)-acetoin was accomplished using a strain where the competing lactate, acetate and ethanol forming pathways had been blocked. By introducing different alcohol dehydrogenases into this strain, either EcBDH from Enterobacter cloacae or SadB from Achromobacter xylosooxidans, it was possible to achieve high-yield production of m-BDO or R-BDO respectively. To achieve biosustainable production of these chemicals from dairy waste, we transformed the above strains with the lactose plasmid pLP712. This enabled efficient production of (3R)-acetoin, m-BDO and R-BDO from processed whey waste, with titers of 27, 51, and 32 g/L respectively. The corresponding yields obtained were 0.42, 0.47 and 0.40 g/g lactose, which is 82%, 89%, and 76% of maximum theoretical yield respectively. These results clearly demonstrate that L. lactis is an excellent choice as a cell factory for transforming lactose containing dairy waste into value added chemicals.
authors.affiliation: National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Vijayalakshmi
authors.initials: V
authors.lastname: Kandasamy
authors.affiliation: National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Jianming
authors.initials: J
authors.lastname: Liu
authors.affiliation: National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Shruti Harnal
authors.initials: SH
authors.lastname: Dantoft
authors.affiliation: National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Solem
authors.affiliation: National Food Institute, Technical University of Denmark, DK-2800 Kgs. Lyngby, Denmark.
authors.forename: Peter Ruhdal
authors.initials: PR
authors.lastname: Jensen
mesh_terms: D000093:Acetoin / Q000302:isolation & purification / Q000378:metabolism*; D042441:Achromobacter denitrificans / Q000235:genetics; D000426:Alcohol Dehydrogenase / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D019149:Bioreactors; D053898:Biosynthetic Pathways; D002072:Butylene Glycols / Q000302:isolation & purification / Q000378:metabolism*; D016972:Enterobacter cloacae / Q000235:genetics; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism*; D060847:Metabolic Engineering; D009097:Multienzyme Complexes / Q000096:biosynthesis / Q000235:genetics; D009247:NADH, NADPH Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D013237:Stereoisomerism
chemical_list: D001426:Bacterial Proteins; D002072:Butylene Glycols; D009097:Multienzyme Complexes; C026978:2,3-butylene glycol; D000093:Acetoin; D000426:Alcohol Dehydrogenase; C023107:NADH oxidase; D009247:NADH, NADPH Oxidoreductases