Homo- d -Lactic Acid Fermentation from Arabinose by Redirection of the Phosphoketolase Pathway to the Pentose Phosphate Pathway in l -Lactate Dehydrogenase Gene-Deficient Lactobacillus plantarum

Abstract

Optically pure d-lactic acid fermentation from arabinose was achieved by using the Lactobacillus plantarum NCIMB 8826 strain whose l-lactate dehydrogenase gene was deficient and whose phosphoketolase gene was substituted with a heterologous transketolase gene. After 27 h of fermentation, 38.6 g/liter of d-lactic acid was produced from 50 g/liter of arabinose.

A Human Gut Commensal Ferments Cranberry Carbohydrates To Produce Formate

“…Lactobacillus strains may utilize carbohydrates as well as bifidobacteria (47). It is likely that L. plantarum uses the phosphoketolase pathway while consuming xyloglucans to secrete formate and acetate, with lactate being reduced (48,49). This was previously observed in L. plantarum VTT E-79098 fermentation of arabino-xylooligosaccharide (33).…”

Improved Production of Homo- d -Lactic Acid via Xylose Fermentation by Introduction of Xylose Assimilation Genes and Redirection of the Phosphoketolase Pathway to the Pentose Phosphate Pathway in l -Lactate Dehydrogenase Gene-Deficient Lactobacillus plantarum

“…We had previously disrupted the PK pathway by deletion of the phosphoketolase 1 gene (xpk1) in an L-lactate dehydrogenase gene (ldhL1)-deficient L. plantarum NCIMB 8826 strain which produces optically pure D-lactic acid (10) and introduced the PP pathway by introduction of the transketolase gene from Lactococcus lactis IL 1403 (tkt) into this strain. The resulting mutant, L. plantarum ⌬ldhL1-xpk1::tkt, successfully produces only lactic acid (exhibiting homo-lactic acid production) from arabinose that is metabolized via an intermediate compound, X5P (3), which is also an intermediate compound in xylose conversion (9). Therefore, the goal of this study was to achieve homo-D-lactic acid production from xylose by expanding the uses of the L. plantarum ⌬ldhL1-xpk1::tkt strain.…”

“…Encouraged by these findings, we carried out lactic acid production via fermentation of 50 g/liter of xylose by using L. plantarum ⌬ldhL1/pCU-PXylAB and L. plantarum ⌬ldhL1-xpk1::tkt/pCU-PXylAB strains in a 2.0-liter bioreactor as described previously (9), with the addition of erythromycin (final concentration, 25 g/ml) to the fermentor. The temperature was maintained at 36°C, the agitation speed was maintained at 100 rpm, and the pH was kept at approximately 6.0 (Ϯ0.03) by the automatic addition of 10 M NH 3 solution.…”

“…The temperature was maintained at 36°C, the agitation speed was maintained at 100 rpm, and the pH was kept at approximately 6.0 (Ϯ0.03) by the automatic addition of 10 M NH 3 solution. Xylose, lactic acid, and acetic acid concentrations were measured by highperformance liquid chromatography, as described previously (9). The optical purity of lactic acid was measured using a BF-5 biosensor (Oji Scientific Instruments, Hyogo, Japan) as described previously (6).…”

Genetically Engineered Lactobacilli for Technological and Functional Food Applications

“…Recombinant strategies have also been used in Lactobacillus strains to produce lactic acid from sugars others than glucose and from biomass such as starch and cellulose. In an L. plantarum ldhL1 strain, that only produced Dlactate from glucose, the phosphoketolase gene was substituted by a transketolase gene from L. lactis, and the resulting L. plantarum ldhL1-xpk1::tkt strain produced 38.6 g/l of Dlactate from 50 g/l of arabinose (Okano et al, 2009). The production of D-lactate from xylose was also achieved in L. plantarum by disrupting a phosphoketolase 2 gene in the L. plantarum ldhL1-xpk1::tkt strain and transforming it with a plasmid that contains the genes xylAB.…”