title: Diacetyl and acetoin production from whey permeate using engineered Lactobacillus casei.
abstract: The capability of Lactobacillus casei to produce the flavor-related compounds diacetyl and acetoin from whey permeate has been examined by a metabolic engineering approach. An L. casei strain in which the ilvBN genes from Lactococcus lactis, encoding acetohydroxyacid synthase, were expressed from the lactose operon was mutated in the lactate dehydrogenase gene (ldh) and in the pdhC gene, which codes for the E2 subunit of the pyruvate dehydrogenase complex. The introduction of these mutations resulted in an increased capacity to synthesize diacetyl/acetoin from lactose in whey permeate (1,400 mg/l at pH 5.5). The results showed that L. casei can be manipulated to synthesize added-value metabolites from dairy industry by-products.
authors.affiliation: Laboratorio de Bacterias Lácticas y Probióticos, Instituto de Agroquímica y Tecnología de Alimentos-CSIC, 46100 Burjassot, Valencia, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Nadal
authors.forename: Juan
authors.initials: J
authors.lastname: Rico
authors.forename: Gaspar
authors.initials: G
authors.lastname: Pérez-Martínez
authors.forename: María J
authors.initials: MJ
authors.lastname: Yebra
authors.forename: Vicente
authors.initials: V
authors.lastname: Monedero
mesh_terms: D000093:Acetoin / Q000378:metabolism*; D000095:Acetolactate Synthase / Q000235:genetics / Q000378:metabolism; D001709:Biotechnology / Q000379:methods; D003470:Culture Media; D003931:Diacetyl / Q000378:metabolism; D005285:Fermentation; D005818:Genetic Engineering / Q000379:methods*; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D007780:Lacticaseibacillus casei / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D007785:Lactose / Q000378:metabolism; D008894:Milk Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics; D000067816:Whey Proteins
chemical_list: D003470:Culture Media; D008894:Milk Proteins; D011768:Pyruvate Dehydrogenase Complex; D000067816:Whey Proteins; D000093:Acetoin; D007770:L-Lactate Dehydrogenase; D000095:Acetolactate Synthase; D007785:Lactose; D003931:Diacetyl