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

Okano, Kenji; Yoshida, Shogo; Yamada, R.; Tanaka, Tsutomu; Ogino, Chiaki; Fukuda, Hideki; Kondo, Akihiko

doi:10.1128/aem.01692-09

Cited by 91 publications

(54 citation statements)

References 11 publications

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“…The tricarboxylic acid (TCA) cycle and gluconeogenesis are known to be nonfunctional in most lactic acid bacteria, including L. plantarum and L. fermentum (30, 31) (www.genome.jp) and were thus not considered in the model. The pentose phosphate pathway is also nonfunctional in L. fermentum (lack of transketolase and transaldolase) (www.genome.jp) and was found to be inactive in L. plantarum (32). Furthermore, preliminary simulations revealed no significant differences in the flux profile of L. plantarum when the pentose phosphate pathway was considered in the metabolic model.…”

Section: Strainsmentioning

confidence: 99%

Core Fluxome and Metafluxome of Lactic Acid Bacteria under Simulated Cocoa Pulp Fermentation Conditions

Adler

Bolten

Dohnt

et al. 2013

Appl Environ Microbiol

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bIn the present work, simulated cocoa fermentation was investigated at the level of metabolic pathway fluxes (fluxome) of lactic acid bacteria (LAB), which are typically found in the microbial consortium known to convert nutrients from the cocoa pulp into organic acids. A comprehensive 13 C labeling approach allowed to quantify carbon fluxes during simulated cocoa fermentation by (i) parallel 13 C studies with [ 13 C 6 ]glucose, [1,2-13 C 2 ]glucose, and [ 13 C 6 ]fructose, respectively, (ii) gas chromatography-mass spectrometry (GC/MS) analysis of secreted acetate and lactate, (iii) stoichiometric profiling, and (iv) isotopomer modeling for flux calculation. The study of several strains of L. fermentum and L. plantarum revealed major differences in their fluxes. The L. fermentum strains channeled only a small amount (4 to 6%) of fructose into central metabolism, i.e., the phosphoketolase pathway, whereas only L. fermentum NCC 575 used fructose to form mannitol. In contrast, L. plantarum strains exhibited a high glycolytic flux. All strains differed in acetate flux, which originated from fractions of citrate (25 to 80%) and corresponding amounts of glucose and fructose. Subsequent, metafluxome studies with consortia of different L. fermentum and L. plantarum strains indicated a dominant (96%) contribution of L. fermentum NCC 575 to the overall flux in the microbial community, a scenario that was not observed for the other strains. This highlights the idea that individual LAB strains vary in their metabolic contribution to the overall fermentation process and opens up new routes toward streamlined starter cultures. L. fermentum NCC 575 might be one candidate due to its superior performance in flux activity.T he worldwide annual production of cocoa beans has reached 4.4 million metric tons (1 [http://faostat3.fao.org/home/index .html#DOWNLOAD; selection: production Ͼ crops Ͼ regions: world {total} Ͼ elements: production {tonnes} Ͼ items: cocoa beans Ͼ years: 2011]). The process of chocolate preprocessing involves pod opening, bean (pulp) fermentation, and bean drying, followed by roasting of the cocoa beans (2). A critical step determining the cocoa bean quality is the fermentation of the fresh cocoa pulp, whose main functions are acetic acid-and heat-induced death of the cocoa bean, reduction in bitterness, and formation of valuable aroma precursors (3). Cocoa bean fermentation is a spontaneous process that is carried out under rather uncontrolled conditions. Thus, the result of the fermentation process strongly depends on the microbial population of the pulp and postharvest practices on the farm (4). It was shown recently that lactic acid bacteria (LAB) play a prominent role in the microbial community of cocoa pulp fermentation, as their metabolic contribution is a key to the success of the fermentation process (5, 6). The primary routes of carbon metabolism by lactobacilli are summarized in Fig. 1. The LAB convert carbohydrates, i.e., fructose and glucose, and citrate, contained in the pulp, into lactate, aceta...

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Section: Strainsmentioning

confidence: 99%

Core Fluxome and Metafluxome of Lactic Acid Bacteria under Simulated Cocoa Pulp Fermentation Conditions

Adler

Bolten

Dohnt

et al. 2013

Appl Environ Microbiol

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“…Interestingly, Lactobacillus species are predominant in contaminated ethanol fermentations (4,5), and L. plantarum shows high ethanol tolerance (6), rendering it as a possible candidate for the production of biofuel by introduction of ethanol-producing enzymes into its genetic repertoire (7). In contrast to the commonly used ethanol-producing yeast Saccharomyces cerevisiae, L. plantarum is able to metabolize pentose sugars derived from lignocellulosic biomass (8)(9)(10)(11). The production of acid and the bacterium's acid tolerance reduces the risk of contamination by other bacteria and fungi and may enable degradation of substrates directly after acid pretreatments that are commonly used for lignin deconstruction in plant biomass.…”

mentioning

confidence: 99%

Establishment of a Simple Lactobacillus plantarum Cell Consortium for Cellulase-Xylanase Synergistic Interactions

Moraïs

Shterzer

Grinberg

et al. 2013

Appl Environ Microbiol

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Lactobacillus plantarum is an attractive candidate for bioprocessing of lignocellulosic biomass due to its high metabolic variability, including its ability to ferment both pentoses and hexoses, as well as its high acid tolerance, a quality often utilized in industrial processes. This bacterium grows naturally on biomass; however, it lacks the inherent ability to deconstruct lignocellulosic substrates. As a first step toward engineering lignocellulose-converting lactobacilli, we have introduced genes coding for a GH6 cellulase and a GH11 xylanase from a highly active cellulolytic bacterium into L. plantarum. For this purpose, we employed the recently developed pSIP vectors for efficient secretion of heterologous proteins. Both enzymes were secreted by L. plantarum at levels estimated at 0.33 nM and 3.3 nM, for the cellulase and xylanase, respectively, in culture at an optical density at 600 nm (OD 600 ) of 1. Transformed cells demonstrated the ability to degrade individually either cellulose or xylan and wheat straw. When mixed together to form a two-strain cell-based consortium secreting both cellulase and xylanase, they exhibited synergistic activity in the overall release of soluble sugar from wheat straw. This result paves the way toward metabolic harnessing of L. plantarum for novel biorefining applications, such as production of ethanol and polylactic acid directly from plant biomass.

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“…1) (8,(16)(17)(18). Attempts to improve the xylose fermentation properties of these lactic acid bacteria have met with limited success (18,19). Although all the pentoses in hemicellulose are efficiently fermented by the E. coli derivatives to D(−)-or L(+)-lactic acid through the pentose-phosphate pathway, the temperature and pH tolerances of this microbial biocatalyst are insufficient to permit cellulosic fermentations at the conditions that are optimal (50°C and pH 5.0) for commercial cellulases (20).…”

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confidence: 99%

Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose

Wang

Ingram

Shanmugam

2011

Proc. Natl. Acad. Sci. U.S.A.

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Lactic acid, an attractive, renewable chemical for production of biobased plastics (polylactic acid, PLA), is currently commercially produced from food-based sources of sugar. Pure optical isomers of lactate needed for PLA are typically produced by microbial fermentation of sugars at temperatures below 40°C. Bacillus coagulans produces L(+)-lactate as a primary fermentation product and grows optimally at 50°C and pH 5, conditions that are optimal for activity of commercial fungal cellulases. This strain was engineered to produce D(−)-lactate by deleting the native ldh (L-lactate dehydrogenase) and alsS (acetolactate synthase) genes to impede anaerobic growth, followed by growth-based selection to isolate suppressor mutants that restored growth. One of these, strain QZ19, produced about 90 g L −1 of optically pure D(−)-lactic acid from glucose in <48 h. The new source of D-lactate dehydrogenase (D-LDH) activity was identified as a mutated form of glycerol dehydrogenase (GlyDH; D121N and F245S) that was produced at high levels as a result of a third mutation (insertion sequence). Although the native GlyDH had no detectable activity with pyruvate, the mutated GlyDH had a D-LDH specific activity of 0.8 μmoles min −1 ðmg proteinÞ −1 . By using QZ19 for simultaneous saccharification and fermentation of cellulose to D-lactate (50°C and pH 5.0), the cellulase usage could be reduced to 1∕3 that required for equivalent fermentations by mesophilic lactic acid bacteria. Together, the native B. coagulans and the QZ19 derivative can be used to produce either L(+) or D(−) optical isomers of lactic acid (respectively) at high titers and yields from nonfood carbohydrates.

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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

Cited by 91 publications

References 11 publications

Core Fluxome and Metafluxome of Lactic Acid Bacteria under Simulated Cocoa Pulp Fermentation Conditions

Core Fluxome and Metafluxome of Lactic Acid Bacteria under Simulated Cocoa Pulp Fermentation Conditions

Establishment of a Simple Lactobacillus plantarum Cell Consortium for Cellulase-Xylanase Synergistic Interactions

Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose

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