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1.
Microb Biotechnol ; 17(3): e14384, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38454531

RESUMO

Plastic usage by microbes as a carbon source is a promising strategy to increase the recycling quota. 1,4-butanediol (BDO) is a common monomer derived from polyesters and polyurethanes. In this study, Ustilago trichophora was found to be an efficient cell-factory to valorize BDO. To investigate product formation by U. trichophora, we refined the traditional ion exclusion liquid chromatography method by examining eluent, eluent concentrations, oven temperatures, and organic modifiers to make the chromatography compatible with mass spectrometry. An LC-UV/RI-MS2 method is presented here to identify and quantify extracellular metabolites in the cell cultures. With this method, we successfully identified that U. trichophora secreted malic acid, succinic acid, erythritol, and mannitol into the culture medium. Adaptive laboratory evolution followed by medium optimization significantly improved U. trichophora growth on BDO and especially malic acid production. Overall, the carbon yield on the BDO substrate was approximately 33% malic acid. This study marks the first report of a Ustilaginaceae fungus capable of converting BDO into versatile chemical building blocks. Since U. trichophora is not genetically engineered, it is a promising microbial host to produce malic acid from BDO, thereby contributing to the development of the envisaged sustainable bioeconomy.


Assuntos
Basidiomycota , Butileno Glicóis , Carbono , Malatos , Poliuretanos , Fermentação
2.
Bioresour Technol ; 398: 130532, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38447618

RESUMO

Schizochytrium sp. hasreceived much attention for itsability to synthesize and accumulate high-level docosahexaenoic acid (DHA), which can reach nearly 40 % of total fatty acids. In this study, the titer of DHA in Schizochytrium sp. was successfully improved by enhancing DHA storage through overexpressing the diacylglycerol acyltransferase (ScDGAT2C) gene, as well as optimizing the supply of precursors and cofactors required for DHA synthesis by response surface methodology. Notably, malic acid, citric acid, and biotin showed synergistic and time-dependent effects on DHA accumulation. The maximum lipid and DHA titers of the engineered Schizochytrium sp. strain reached 84.28 ± 1.02 g/L and 42.23 ± 0.69 g/L, respectively, with the optimal concentration combination (1.62 g/L malic acid + 0.37 g/L citric acid + 8.28 mg/L biotin) were added 48 h after inoculation. This study provides an effective strategy for improving lipid and DHA production in Schizochytrium sp.


Assuntos
Ácidos Graxos , Malatos , Estramenópilas , Fermentação , Ácidos Docosa-Hexaenoicos , Biotina , Estramenópilas/genética , Ácido Cítrico
3.
J Agric Food Chem ; 72(11): 5797-5804, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38465388

RESUMO

Biological production of citramalate has garnered attention due to its wide application for food additives and pharmaceuticals, although improvement of yield is known to be challenging. When glucose is used as the sole carbon source, carbon loss through decarboxylation steps for providing acetyl-CoA from pyruvate is inevitable. To avoid this, we engineered a strain to co-utilize glucose and cost-effective acetate while preventing carbon loss for enhancing citramalate production. The production pathway diverged to independently supply the precursors required for the synthesis of citramalate from glucose and acetate, respectively. Moreover, the phosphotransferase system was inactivated and the acetate assimilation pathway and the substrate ratio were optimized to enable the simultaneous and efficient utilization of both carbon sources. This yielded results (5.0 g/L, 0.87 mol/mol) surpassing the yield and titer of the control strain utilizing glucose as the sole carbon source in flask cultures, demonstrating an economically efficient strain redesign strategy for synthesizing various products.


Assuntos
Escherichia coli , Malatos , Engenharia Metabólica , Escherichia coli/genética , Glucose/metabolismo , Acetatos/metabolismo , Carbono/metabolismo
4.
Lung Cancer ; 190: 107541, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38531154

RESUMO

OBJECTIVE: Metabolic reprogramming is an important coordinator of tumor development and resistance to therapy, such as the tendency of tumor cells to utilize glycolytic energy rather than oxidative phosphorylation, even under conditions of sufficient oxygen. Therefore, targeting metabolic enzymes is an effective strategy to overcome therapeutic resistance. MATERIALS AND METHODS: We explored the differential expression and growth-promoting function of MDH2 by immunohistochemistry and immunoblotting experiments in lung cancer patients and lung cancer cells. Pentose phosphate pathway-related phenotypes (including ROS levels, NADPH levels, and DNA synthesis) were detected intracellularly, and the interaction of malate and proteinase 6PGD was detected in vitro. In vivo experiments using implanted xenograft mouse models to explore the growth inhibitory effect and pro-chemotherapeutic function of dimethyl malate (DMM) on lung cancer. RESULTS: We found that the expression of malate dehydrogenase (MDH2) in the tricarboxylic acid cycle (TCA cycle) was increased in lung cancer. Biological function enrichment analysis revealed that MDH2 not only promoted oxidative phosphorylation, but also promoted the pentose phosphate pathway (PPP pathway). Mechanistically, it was found that malate, the substrate of MDH2, can bind to the PPP pathway metabolic enzyme 6PGD, inhibit its activity, reduce the generation of NADPH, and block DNA synthesis. More importantly, DMM can improve the sensitivity of lung cancer to the clinical drug cisplatin. CONCLUSION: We have identified malate as a natural inhibitor of 6PGD, which will provide new leads for the development of 6PGD inhibitors. In addition, the metabolic enzyme MDH2 and the metabolite malate may provide a backup option for cells to inhibit their own carcinogenesis, as the accumulated malate targets 6PGD to block the PPP pathway and inhibit cell cycle progression.


Assuntos
Neoplasias Pulmonares , Humanos , Animais , Camundongos , Neoplasias Pulmonares/genética , NADP/metabolismo , Malatos , DNA
5.
Plant Physiol Biochem ; 208: 108535, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38503187

RESUMO

Aluminum (Al) toxicity is the major constraint on plant growth and productivity in acidic soils. An adaptive mechanism to enhance Al tolerance in plants is mediated malate exudation from roots through the involvement of ALMT (Al-activated malate transporter) channels. The underlying Al tolerance mechanisms of stylo (Stylosanthes guianensis), an important tropical legume that exhibits superior Al tolerance, remain largely unknown, and knowledge of the potential contribution of ALMT genes to Al detoxification in stylo is limited. In this study, stylo root growth was inhibited by Al toxicity, accompanied by increases in malate and citrate exudation from roots. A total of 11 ALMT genes were subsequently identified in the stylo genome and named SgALMT1 to SgALMT11. Diverse responses to metal stresses were observed for these SgALMT genes in stylo roots. Among them, the expressions of 6 out of the 11 SgALMTs were upregulated by Al toxicity. SgALMT2, a root-specific and Al-activated gene, was selected for functional characterization. Subcellular localization analysis revealed that the SgALMT2 protein is localized to the plasma membrane. The function of SgALMT2 in mediating malate release was confirmed by analysis of the malate exudation rate from transgenic composite stylo plants overexpressing SgALMT2. Furthermore, overexpression of SgALMT2 led to increased root growth in transgenic stylo plants treated with Al through decreased Al accumulation in roots. Taken together, the results of this study suggest that malate secretion mediated by SgALMT2 contributes to the ability of stylo to cope with Al toxicity.


Assuntos
Alumínio , Fabaceae , Alumínio/toxicidade , Alumínio/metabolismo , Malatos/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Fabaceae/metabolismo
6.
Molecules ; 29(5)2024 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-38474454

RESUMO

A green extraction method was developed using deep eutectic solvent extraction for the polysaccharide from Acanthopanax senticosus (A. senticosus). Among the eight types of DES prepared, the DES with a ratio of 1:4 L-malic acid to L-proline was found to be a suitable extraction solvent based on the extraction efficiency. The extraction parameters were optimized by Plackett-Burman and response surface methodology (RSM). The best extraction conditions were found for L-malic acid. Under the conditions of an L-malic acid/L-proline ratio of 1:4, ultrasonic power of 240 W, material-liquid ratio of 31.068 g/mL, water content of 32.364%, extraction time of 129.119 min, and extraction temperature of 60 °C, the extraction rate of A. senticosus polysaccharides was 35.452 ± 0.388 mg-g-1. This rate was higher than that of polysaccharides obtained by hot water extraction (13.652 ± 0.09 mg-g-1). The experimental results were best fitted by the quasi-secondary kinetic model when compared to two other kinetic models. Electron microscopic observations showed that DESs were more destructive to plant cells. The polysaccharide extracted from DESs had more monosaccharide components, a lower molecular weight, a higher antioxidant capacity, and superior anti-glycation activity compared to polysaccharides extracted from water (ASPS-PW). This study demonstrates the effectiveness of DESs in obtaining polysaccharides from A. senticosus.


Assuntos
Eleutherococcus , Malatos , Solventes , Solventes Eutéticos Profundos , Água , Polissacarídeos , Prolina
7.
J Agric Food Chem ; 72(12): 6110-6117, 2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38372212

RESUMO

Establishing a platform for the bioconversion of waste resources into value-added compounds is critical for achieving a sustainable and eco-friendly economy. Herein, we produced polyhydroxyalkanoate via microbial fermentation using cabbage waste as a feedstock and metabolically engineered Escherichia coli. For this, the hydrolysis conditions of cabbage waste were optimized by focusing on parameters such as substrate and enzyme concentrations to enhance the saccharification efficiency. The phaABC operon, which encodes key enzymes responsible for polyhydroxyalkanoate biosynthesis in Ralstonia eutropha H16, was overexpressed in E. coli. Using cabbage hydrolysate as the feedstock, this engineered E. coli strain could produce poly(3-hydroxybutyrate) with a polymer content of 26.0 wt % of dry cell weight. Moreover, malic acid in cabbage hydrolysate significantly enhanced poly(3-hydroxybutyrate) production; the addition of 0.5 g/L malic acid markedly increased poly(3-hydroxybutyrate) content by 59.9%. This study demonstrates the potential of cabbage waste as a promising raw material for the microbial production of polyhydroxyalkanoate.


Assuntos
Brassica , Malatos , Poli-Hidroxialcanoatos , Escherichia coli , Hidrólise , Ácido 3-Hidroxibutírico
8.
Int J Biol Macromol ; 263(Pt 1): 130236, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38367786

RESUMO

The effects of microwave combined with L-malic acid treatment on the degree of substitution (DS), structure, physicochemical properties, and digestibility of sweet potato starch (A-type), potato starch (B-type), and pea starch (C-type) were evaluated. The order of DS obtained was: DSM-POS > DSM-SPS > DSM-PES. Fourier transform-infrared spectroscopy (FT-IR) showed that the obtained modified starch produced a new absorption band at 1735 cm-1. Scanning electron microscopy (SEM) and polarized light microscopy indicated that different types of native starches exhibited different granular morphologies and appeared to have different degrees of damage, but still had polarized crosses after modification. Sweet potato starch had the smallest particle size, while potato starch had the largest. X-ray diffractometry (XRD) showed that the modified starches still retained the same crystal structure as the native starches, but the relative crystallinity decreased. The apparent viscosity and swelling power of modified starches dropped, but their water/oil holding capacity, amylose content, and resistant starch content all increased. The results demonstrate that the degree of influence on the structure, physicochemical properties, and digestibility of different starches varies under the same modification conditions.


Assuntos
Ipomoea batatas , Malatos , Amido , Amido/química , Micro-Ondas , Ésteres , Espectroscopia de Infravermelho com Transformada de Fourier , Amilose/química , Ipomoea batatas/química , Difração de Raios X
9.
Microb Biotechnol ; 17(2): e14410, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38298109

RESUMO

Although a high titre of malic acid is achieved by filamentous fungi, by-product succinic acid accumulation leads to a low yield of malic acid and is unfavourable for downstream processing. Herein, we conducted a series of metabolic rewiring strategies in a previously constructed Myceliophthora thermophila to successfully improve malate production and abolish succinic acid accumulation. First, a pyruvate carboxylase CgPYC variant with increased activity was obtained using a high-throughput system and introduced to improve malic acid synthesis. Subsequently, shifting metabolic flux to malate synthesis from mitochondrial metabolism by deleing mitochondrial carriers of pyruvate and malate, led to a 53.7% reduction in succinic acid accumulation. The acceleration of importing cytosolic succinic acid into the mitochondria for consumption further decreased succinic acid formation by 53.3%, to 2.12 g/L. Finally, the importer of succinic acid was discovered and used to eliminate by-product accumulation. In total, malic acid production was increased by 26.5%, relative to the start strain JG424, to 85.23 g/L and 89.02 g/L on glucose and Avicel, respectively, in the flasks. In a 5-L fermenter, the titre of malic acid reached 182.7 g/L using glucose and 115.8 g/L using raw corncob, without any by-product accumulation. This study would accelerate the industrial production of biobased malic acid from renewable plant biomass.


Assuntos
Malatos , Sordariales , Ácido Succínico , Ácido Succínico/metabolismo , Malatos/metabolismo , Malato Desidrogenase/metabolismo , Succinatos , Ácido Pirúvico/metabolismo , Glucose/metabolismo
10.
Food Res Int ; 179: 114027, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38342547

RESUMO

Oenococcus oeni is the lactic acid bacteria most suited to carry out malolactic fermentation in wine, converting L-malic acid into L-lactic acid and carbon dioxide, thereby deacidifying wines. Indeed, wine is a harsh environment for microbial growth, partly because of its low pH. By metabolizing citrate, O. oeni maintains its homeostasis under acid conditions. Indeed, citrate consumption activates the proton motive force, helps to maintain intracellular pH, and enhances bacterial growth when it is co-metabolized with sugars. In addition, citrate metabolism is responsible for diacetyl production, an aromatic compound which bestows a buttery character to wine. However, an inhibitory effect of citrate on O. oeni growth at low pH has been highlighted in recent years. In order to understand how citrate metabolism can be linked to the acid tolerance of this bacterium, consumption of citrate was investigated in eleven O. oeni strains. In addition, malate and sugar consumptions were also monitored, as they can be impacted by citrate metabolism. This experiment highlighted the huge diversity of metabolisms between strains depending on their origin. It also showed the capacity of O. oeni to de novo metabolize certain end-products such as L-lactate and mannitol, a phenomenon never before demonstrated. It also enabled drawing hypotheses concerning the two positive effects that the slowing down of citrate metabolism could have on biomass production and malolactic fermentation occurring under low pH conditions.


Assuntos
Ácido Cítrico , Malatos , Oenococcus , Vinho , Fermentação , Vinho/análise , Açúcares , Concentração de Íons de Hidrogênio
11.
Food Res Int ; 179: 114033, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38342553

RESUMO

Elucidating the driving mechanism of microbial community succession during pepper fermentation contributes to establishing efficient fermentation regulation strategies. This study utilized three-generation high-throughput sequencing technology, microbial co-occurrence network analysis, and random forest analysis to reveal microbial community succession processes and driving mechanisms during pepper fermentation. The results showed that more positive correlations than negative correlations were observed among microorganisms, with positive correlation proportions of 60 %, 51.03 %, and 71.43 % between bacteria and bacteria, fungi and fungi, and bacteria and fungi in sipingtou peppers, and 69.23 %, 54.93 %, and 79.44 % in zhudachang peppers, respectively. Microbial interactions, mainly among Weissella hellenica, Lactobacillus plantarum, Hanseniaspora opuntiae, and Kazachstania humillis, could drive bacterial and fungal community succession. Notably, the bacterial community successions during the fermentation of two peppers were similar, showing the transition from Leuconostoc pseudomesenteroides, Lactococcus lactis, Weissella ghanensis to Weissella hellenica and Lactobacillus plantarum. However, the fungal community successions in the two fermented peppers differed significantly, and the differential biomarkers were Dipodascus geotrichum and Kazachstania humillis. Differences in autochthonous microbial composition and inherent constituents brought by pepper varieties resulted in different endogenous environmental changes, mainly in fructose, malic acid, and citric acid. Furthermore, endogenous environmental factors could also drive microbial community succession, with succinic acid, lactic acid, and malic acid being the main potential drivers of bacterial community succession, whereas fructose, glucose, and succinic acid were the main drivers of fungal community succession. These results will provide insights into controlling fermentation processes by raw material combinations, optimization of environmental parameters, and microbial interactions.


Assuntos
Lactobacillus plantarum , Malatos , Microbiota , Saccharomycetales , Weissella , Fermentação , Ácido Succínico , Bactérias/genética , Interações Microbianas , Frutose
12.
J Agric Food Chem ; 72(9): 4869-4879, 2024 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-38407053

RESUMO

The efficient production of l-malic acid using Aspergillus niger requires overcoming challenges in synthesis efficiency and excessive byproduct buildup. This study addresses these hurdles, improving the activity of NADH-dependent malate dehydrogenase (Mdh) in the early stages of the fermentation process. By employing a constitutive promoter to express the Escherichia coli sthA responsible for the transfer of reducing equivalents between NAD(H) and NADP(H) in A. niger, the l-malic acid production was significantly elevated. However, this resulted in conidiation defects of A. niger, limiting industrial viability. To mitigate this, we discovered and utilized the PmfsA promoter, enabling the specific expression of sthA during the fermentation stage. This conditional expression strain showed similar phenotypes to its parent strain while exhibiting exceptional performance in a 5 L fermenter. Notably, it achieved a 65.5% increase in productivity, reduced fermentation cycle by 1.5 days, and lowered succinic acid by 76.2%. This work marks a promising advancement in industrial l-malic acid synthesis via biological fermentation, showcasing the potential of synthetic biology in A. niger for broader applications.


Assuntos
Aspergillus niger , Aspergillus , Malatos , Aspergillus niger/genética , Aspergillus niger/metabolismo , Malatos/metabolismo , Fermentação , Escherichia coli/genética , Escherichia coli/metabolismo , NAD/metabolismo , Expressão Gênica
13.
Chem Biol Drug Des ; 103(1): e14445, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38230786

RESUMO

Lung adenocarcinoma (LUAD) is the most common subtype of lung cancer with a low 5-year survival rate. ANKRD22 is an ankyrin repeat protein capable of promoting tumor progression, and its mechanism in LUAD remains elusive. Our study aims to investigate the mechanisms underlying the involvement of ANKRD22 in the progression of LUAD. The expression of ANKRD22 in LUAD and its enriched pathway were analyzed by bioinformatics analysis. Meanwhile, the correlation between ANKRD22 and the expression of glycolysis-related genes and M2 macrophage marker genes was analyzed. qRT-PCR was used for determination of the expression of ANKRD22, IL-10 and CCL17, CCK-8 for cell viability, and western blot for expression of ANKRD22, LDHA, HK2, PGK1, and PKM2. Immunofluorescence and flow cytometry were utilized to examine the level of CD163, and kits were used to measure the contents of pyruvic acid, lactate, citrate, and malate. Seahorse XF96 analyzer was employed to determine extracellular acidification rate (ECAR) and oxygen consumption rate (OCR). Mitochondrial membrane potential was assessed using the JC-1 probe. Bioinformatics analysis, qRT-PCR, and western blot showed that ANKRD22 was highly expressed in LUAD, which had a positive connection with M2 marker genes. Knockdown of ANKRD22 considerably attenuated the expression of ANKRD22, IL-10, and CCL17 in M2. ANKRD22 overexpression demonstrated the opposite results. Bioinformatics analysis uncovered that ANKRD22 was enriched in the glycolytic pathway and positively correlated with glycolysis-related genes. The knockdown of ANKRD22 substantially attenuated pyruvic acid, lactate, citrate, malate, and ECAR levels and elevated OCR levels in cells. The knockdown of ANKRD22 also reduced mitochondrial membrane potential. Further, it was discovered that glycolysis-related genes had a positive correlation with M2 marker genes. It was revealed by rescue experiments that the usage of 2-DG, a glycolytic inhibitor, remarkably reversed the facilitating effect of overexpression of ANKRD22 on M2 polarization. This study demonstrates that ANKRD22 can facilitate LUAD M2 polarization through glycolysis, and targeting ANKRD22 to inhibit M2 polarization has the potential to be a new strategy for LUAD treatment.


Assuntos
Adenocarcinoma de Pulmão , Neoplasias Pulmonares , Humanos , Interleucina-10 , Malatos , Ácido Pirúvico , Adenocarcinoma de Pulmão/genética , Citratos , Ácido Cítrico , Lactatos , Proliferação de Células , Linhagem Celular Tumoral
14.
EMBO Rep ; 25(2): 524-543, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38253688

RESUMO

Metabolites derived from the intestinal microbiota play an important role in maintaining skeletal muscle growth, function, and metabolism. Here, we found that D-malate (DMA) is produced by mouse intestinal microorganisms and its levels increase during aging. Moreover, we observed that dietary supplementation of 2% DMA inhibits metabolism in mice, resulting in reduced muscle mass, strength, and the number of blood vessels, as well as the skeletal muscle fiber type I/IIb ratio. In vitro assays demonstrate that DMA decreases the proliferation of vascular endothelial cells and suppresses the formation of blood vessels. In vivo, we further demonstrated that boosting angiogenesis by muscular VEGFB injection rescues the inhibitory effects of D-malate on muscle mass and fiber area. By transcriptomics analysis, we identified that the mechanism underlying the effects of DMA depends on the elevated intracellular acetyl-CoA content and increased Cyclin A acetylation rather than redox balance. This study reveals a novel mechanism by which gut microbes impair muscle angiogenesis and may provide a therapeutic target for skeletal muscle dysfunction in cancer or aging.


Assuntos
Células Endoteliais , Microbiota , Camundongos , Animais , Células Endoteliais/metabolismo , Acetilação , Ciclina A/metabolismo , Malatos/metabolismo , Músculo Esquelético/metabolismo , Envelhecimento
15.
Nat Commun ; 15(1): 422, 2024 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-38212310

RESUMO

To mobilize sparingly available phosphorus (P) in the rhizosphere, many plant species secrete malate to release P sorbed onto (hydr)oxides of aluminum and iron (Fe). In the presence of Fe, malate can provoke Fe over-accumulation in the root apoplast, triggering a series of events that inhibit root growth. Here, we identified HYPERSENSITIVE TO LOW P1 (HYP1), a CYBDOM protein constituted of a DOMON and a cytochrome b561 domain, as critical to maintain cell elongation and meristem integrity under low P. We demonstrate that HYP1 mediates ascorbate-dependent trans-plasma membrane electron transport and can reduce ferric and cupric substrates in Xenopus laevis oocytes and in planta. HYP1 expression is up-regulated in response to P deficiency in the proximal zone of the root apical meristem. Disruption of HYP1 leads to increased Fe and callose accumulation in the root meristem and causes significant transcriptional changes in roots. We further demonstrate that HYP1 activity overcomes malate-induced Fe accumulation, thereby preventing Fe-dependent root growth arrest in response to low P. Collectively, our results uncover an ascorbate-dependent metalloreductase that is critical to protect root meristems of P-deficient plants from increased Fe availability and provide insights into the physiological function of the yet poorly characterized but ubiquitous CYBDOM proteins.


Assuntos
Meristema , Fósforo , Meristema/metabolismo , Fósforo/metabolismo , Malatos/metabolismo , Ferro/metabolismo , Plantas/metabolismo , Ácido Ascórbico/metabolismo , Raízes de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas
16.
J Appl Microbiol ; 135(2)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38268424

RESUMO

AIMS: To assess the capability of Pichia kudriavzevii strains isolated from wine, cider, and natural environments in North Patagonia to produce ciders with reduced malic acid levels. METHODS AND RESULTS: Fermentation kinetics and malic acid consumption were assessed in synthetic media and in regional acidic apple musts. All P. kudriavzevii strains degraded malic acid and grew in synthetic media with malic acid as the sole carbon source. Among these strains, those isolated from cider exhibited higher fermentative capacity, mainly due to increased fructose utilization; however, a low capacity to consume sucrose present in the must was also observed for all strains. The NPCC1651 cider strain stood out for its malic acid consumption ability in high-malic acid Granny Smith apple must. Additionally, this strain produced high levels of glycerol as well as acceptable levels of acetic acid. On the other hand, Saccharomyces cerevisiae ÑIF8 reference strain isolated from Patagonian wine completely consumed reducing sugars and sucrose and showed an important capacity for malic acid consumption in apple must fermentations. CONCLUSIONS: Pichia kudriavzevii NPCC1651 strain isolated from cider evidenced interesting features for the consumption of malic acid and fructose in ciders.


Assuntos
Malatos , Malus , Pichia , Vinho , Frutose/metabolismo , Vinho/análise , Saccharomyces cerevisiae/metabolismo , Fermentação , Ácido Acético/metabolismo , Sacarose/metabolismo
17.
Nat Commun ; 15(1): 846, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38287013

RESUMO

A prevalent side-reaction of succinate dehydrogenase oxidizes malate to enol-oxaloacetate (OAA), a metabolically inactive form of OAA that is a strong inhibitor of succinate dehydrogenase. We purified from cow heart mitochondria an enzyme (OAT1) with OAA tautomerase (OAT) activity that converts enol-OAA to the physiological keto-OAA form, and determined that it belongs to the highly conserved and previously uncharacterized Fumarylacetoacetate_hydrolase_domain-containing protein family. From all three domains of life, heterologously expressed proteins were shown to have strong OAT activity, and ablating the OAT1 homolog caused significant growth defects. In Escherichia coli, expression of succinate dehydrogenase was necessary for OAT1-associated growth defects to occur, and ablating OAT1 caused a significant increase in acetate and other metabolites associated with anaerobic respiration. OAT1 increased the succinate dehydrogenase reaction rate by 35% in in vitro assays with physiological concentrations of both succinate and malate. Our results suggest that OAT1 is a universal metabolite repair enzyme that is required to maximize aerobic respiration efficiency by preventing succinate dehydrogenase inhibition.


Assuntos
Malatos , Succinato Desidrogenase , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo , Malatos/metabolismo , Ciclo do Ácido Cítrico , Mitocôndrias Cardíacas/metabolismo , Oxaloacetatos/metabolismo , Ácido Oxaloacético/metabolismo , Malato Desidrogenase/metabolismo
18.
Bioresour Technol ; 394: 130304, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38211713

RESUMO

Brown macroalgae is a promising feedstock for biorefinery owing to its high biomass productivity and contents of carbohydrates such as alginate and mannitol. However, the limited availability of microbial platforms efficiently catabolizing the brown macroalgae sugars has restricted its utilization. In this study, the direct production of citramalate, an important industrial compound, was demonstrated from brown macroalgae by utilizing Vibrio sp. dhg, which has a remarkably efficient catabolism of alginate and mannitol. Specifically, citramalate synthase from Methanocaldococcus jannaschii was synthetically expressed, and competing pathways were removed to maximally redirect the carbon flux toward citramalate production. Notably, a resulting strain, VXHC, produced citramalate up to 9.8 g/L from a 20 g/L mixture of alginate and mannitol regardless of their ratios. Citramalate was robustly produced even when diverse brown macroalgae were provided directly. Collectively, this study showcased the high potential of brown macroalgae biorefinery using Vibrio sp. dhg.


Assuntos
Malatos , Alga Marinha , Vibrio , Alga Marinha/metabolismo , Manitol/metabolismo , Vibrio/metabolismo , Alginatos/metabolismo
19.
Microb Cell Fact ; 23(1): 8, 2024 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172830

RESUMO

BACKGROUND: One carbon (C1) molecules such as methanol have the potential to become sustainable feedstocks for biotechnological processes, as they can be derived from CO2 and green hydrogen, without the need for arable land. Therefore, we investigated the suitability of the methylotrophic yeast Ogataea polymorpha as a potential production organism for platform chemicals derived from methanol. We selected acetone, malate, and isoprene as industrially relevant products to demonstrate the production of compounds with 3, 4, or 5 carbon atoms, respectively. RESULTS: We successfully engineered O. polymorpha for the production of all three molecules and demonstrated their production using methanol as carbon source. We showed that the metabolism of O. polymorpha is well suited to produce malate as a product and demonstrated that the introduction of an efficient malate transporter is essential for malate production from methanol. Through optimization of the cultivation conditions in shake flasks, which included pH regulation and constant substrate feeding, we were able to achieve a maximum titer of 13 g/L malate with a production rate of 3.3 g/L/d using methanol as carbon source. We further demonstrated the production of acetone and isoprene as additional heterologous products in O. polymorpha, with maximum titers of 13.6 mg/L and 4.4 mg/L, respectively. CONCLUSION: These findings highlight how O. polymorpha has the potential to be applied as a versatile cell factory and contribute to the limited knowledge on how methylotrophic yeasts can be used for the production of low molecular weight biochemicals from methanol. Thus, this study can serve as a point of reference for future metabolic engineering in O. polymorpha and process optimization efforts to boost the production of platform chemicals from renewable C1 carbon sources.


Assuntos
Metanol , Pichia , Pichia/genética , Pichia/metabolismo , Metanol/metabolismo , Malatos/metabolismo , Acetona/metabolismo , Carbono/metabolismo
20.
Int J Food Microbiol ; 413: 110583, 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38277869

RESUMO

In the context of ecological transition, the use of wine by-products for industrial applications is a major challenge. Wine lees, the second wine by-product in terms of quantity, represent a source of nutrients that can be used for stimulating the growth of microorganisms. Here, white wine lees were used as a stimulating agent for the growth of wine lactic acid bacteria (LAB) and to promote wine malolactic fermentation (MLF) driven out by Oenococcus oeni. By adding freeze-dried wine lees to wines under different conditions - including different wine lees at different concentrations and different O. oeni strains at various initial populations - it was observed that wine lees can enhance the growth of LAB and reduce the duration of MLF. The chemical composition of wines was also evaluated, proving that wine lees do not compromise the quality of the wines. In addition, wine lees did not seem to promote the growth of spoilage microorganisms like as Brettanomyces bruxellensis. Altogether, this work reports the possibility of recovering the lees of white wine to obtain a product favoring the MLF of red wines. More general, we propose a recycling strategy of wine by-products to obtain new products for winemaking.


Assuntos
Lactobacillales , Oenococcus , Vinho , Vinho/microbiologia , Fermentação , Malatos
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