Function of hemocyanin-mediated succinate dehydrogenase in glucose metabolism and immunity of Penaeus vannamei.

Succinate dehydrogenase (SDH) is a crucial enzyme in the tricarboxylic acid cycle (TCA) and has established roles in immune function. However, the understanding of SDH in Penaeus vannamei, particularly its involvement in immune responses, is currently limited. Through affinity proteomics, a potential interaction between hemocyanin (HMC) and SDH in shrimp has been identified. The successful cloning of PvSDH in this study has revealed a high degree of evolutionary conservation. Additionally, it has been found that hemocyanin regulates SDH not only at the transcriptional and enzymatic levels but also through confirmed protein-protein interactions observed via Co-immunoprecipitation (CoIP) assay. Moreover, by combining PvHMC knockdown and Vibrio parahaemolyticus challenge, it was demonstrated that fumaric acid, a product of SDH, enhances the host's immune resistance to pathogen infection by modulating the expression of antimicrobial peptides. This research provides new insights into HMC as a crucial regulator of SDH, potentially impacting glycometabolism and the dynamics of immune responses.

Fumaric acid production by Rhizopus species from acid hydrolysate of oil palm empty fruit bunches.

The hemicellulosic fraction of lignocellulosic biomass is a very important material, due to the significant concentration of pentoses present in its composition and that can be used sustainably in biotechnological processes such as the production of fumaric acid. Research efforts are currently being promoted for the proper disposal and valorization of empty fruit bunches (EFB) from oil palm. In this work, seventeen Rhizopus species were evaluated in a fermentation medium with EFB hydrolyzate, without detoxification, as a carbon source for fumaric acid production. Rhizopus circicans 1475 and Rhizopus 3271 achieved productions of 5.65 g.L-1 and 5.25 g.L-1 of fumaric acid at 30 °C, 120 rpm for 96 h, respectively. The percentage of consumed sugars, mainly pentoses, was 24.88% and 34.02% for R. circicans 1475 and R 3271, respectively. Soy peptone and ammonium sulfate were evaluated as nitrogen sources, where soy peptone stimulated the formation of biomass pellets while ammonium sulfate produced mycelia and clamps.

New onset lymphopenia in patients with relapsing multiple sclerosis switching from long-standing dimethyl fumarate treatment to diroximel fumarate: A case series.

Lymphopenia is a known adverse effect in patients with relapsing multiple sclerosis (RMS) treated with fumaric acids. We present a case series of four patients diagnosed with RMS with prolonged lymphocyte stability on dimethyl fumarate for over 1 year who developed significant lymphopenia after transitioning to diroximel fumarate. This case series highlights the need for further research to elucidate the risk of lymphopenia in patients switching between fumaric acids.

Fumaric acid production from fermented oil palm empty fruit bunches using fungal isolate K20: a comparison between free and immobilized cells.

This study investigated the potential of using steam-exploded oil palm empty fruit bunches (EFB) as a renewable feedstock for producing fumaric acid (FA), a food additive widely used for flavor and preservation, through a separate hydrolysis and fermentation process using the fungal isolate K20. The efficiency of FA production by free and immobilized cells was compared. The maximum FA concentration (3.25 g/L), with 0.034 g/L/h productivity, was observed after incubation with the free cells for 96 h. Furthermore, the production was scaled up in a 3-L air-lift fermenter using oil palm EFB-derived glucose as the substrate. The FA concentration, yield, and productivity from 100 g/L initial oil palm EFB-derived glucose were 44 g/L, 0.39 g/g, and 0.41 g/L/h, respectively. The potential for scaling up the fermentation process indicates favorable results, which could have significant implications for industrial applications.

LC-ESI-MS/MS analysis of phenolic compounds and in vitro cytotoxicity and apoptosis-inducing effects of Nonea pulmonarioides extracts.

The chemical composition of Nonea pulmonarioides extracts were investigated for the first time. The phytoconstituents of the methanol extracts were screened by using LC/MS-MS technique. The anticancer activity of the acetone and methanol extracts were measured against four cancer cell lines; MCF-7, PC3, HT-29, and U-87 MG. Thirty phenolic compounds were identified, rosmarinic (90.06 mg analyte/g extract) and fumaric acids (39.737 mg analyte/g extract) were major compounds of the studied species. Moreover, both methanol and acetone extracts were found to have strong anticancer activities. The acetone extract HT-29 (with IC50 of 10.17 ± 0.25 µg/mL) compared with standard cis-platin (with IC50 of 22.20 ± 0.72 µg/mL) with apoptotic mediated programmed cell death. These findings identified N. pulmonarioides as a potential species exhibiting anticancer properties. In conclusion, the compelling results show that the methanol extract contains possible bioactive compounds with anticancer properties that require isolation and further characterisation.

Role of fumarate reductase on the fermentation properties of Lactobacillus delbrueckii ssp. bulgaricus.

Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus are symbiotic starters widely used in yogurt fermentation. They exchange metabolites to meet their nutritional demands during fermentation, promoting mutual growth. Although S. thermophilus produces fumaric acid, and the addition of fumaric acid has been shown to promote the growth of L. bulgaricus monoculture, whether fumaric acid produced by S. thermophilus is used by L. bulgaricus during coculture remains unclear. Furthermore, the importance of fumaric acid metabolism in the growth of L. bulgaricus is yet to be elucidated. Therefore, in this study, we investigated the importance of fumaric acid metabolism in L. bulgaricus monocultures and coculture with S. thermophilus. We deleted the fumarate reductase gene (frd), which is responsible for the metabolism of fumaric acid to succinic acid, in L. bulgaricus strains 2038 and NCIMB 701373. Both Δfrd strains exhibited longer fermentation times than their parent strains, and fumaric acid was metabolized to malic acid rather than succinic acid. Coculture of Δfrd strains with S. thermophilus 1131 also resulted in a longer fermentation time, and the accumulation of malic acid was observed. These results indicated that fumaric acid produced by S. thermophilus is used by L. bulgaricus as a symbiotic substance during yogurt fermentation and that the metabolism of fumaric acid to succinic acid by fumarate reductase is a key factor determining the fermentation ability of L. bulgaricus.

Simultaneous Analysis of Organic Acids, Glycerol and Phenolic Acids in Wines Using Gas Chromatography-Mass Spectrometry.

Fermented beverages, particularly wines, exhibit variable concentrations of organic and phenolic acids, posing challenges in their accurate determination. Traditionally, enzymatic methods or chromatographic analyses, mainly high-performance liquid chromatography (HPLC), have been employed to quantify these compounds individually in the grape must or wine. However, chromatographic analyses face limitations due to the high sugar content in the grape must. Meanwhile, phenolic acids, found in higher quantities in red wines than in white wines, are typically analyzed using HPLC. This study presents a novel method for the quantification of organic acids (OAs), glycerol, and phenolic acids in grape musts and wines. The approach involves liquid-liquid extraction with ethyl acetate, followed by sample derivatization and analysis using gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring (SIM) detection mode. The results indicated successful detection and quantification of all analyzed compounds without the need for sample dilution. However, our results showed that the method of adding external standards was more suitable for quantifying wine compounds, owing to the matrix effect. Furthermore, this method is promising for quantifying other metabolites present in wines, depending on their extractability with ethyl acetate. Fermented beverages, particularly wines, exhibit variable concentrations of organic and phenolic acids, posing challenges in their accurate determination. Traditionally, enzymatic methods or chromatographic analyses, mainly high-performance liquid chromatography (HPLC), have been employed to quantify these compounds individually in the grape must or wine. The approach of this proposed method involves (i) methoximation of wine compounds in a basic medium, (ii) acidification with HCl, (iii) liquid-liquid extraction with ethyl acetate, and (iv) silyl derivatization to analyze samples with gas chromatography-mass spectrometry (GC-MS) in ion monitoring detection mode (SIM). The results indicated successful detection and quantification of all analyzed compounds without the need for sample dilution. However, our results showed that the method of adding external standards was more suitable for quantifying wine compounds, owing to the matrix effect. Furthermore, this method is promising for quantifying other metabolites present in wines, depending on their extractability with ethyl acetate. In other words, the proposed method may be suitable for profiling (targeted) or fingerprinting (untargeted) strategies to quantify wine metabolites or to classify wines according to the type of winemaking process, grape, or fermentation.

Ensitrelvir eradicates persistent SARS-CoV-2 infection in a follicular lymphoma patient treated with anti-CD20 antibodies.

Patients with hematological malignancies, especially B-cell malignancies, who received anti-CD20 antibodies exhibit a poor immune response to the mRNA coronavirus disease 2019 (COVID-19) vaccine within 6-12 months after the last administration. These patients occasionally present with severe COVID-19 symptoms. Additionally, patients with hematologic diseases who have persistent COVID-19 after receiving anti-CD20 antibodies, postpone chemotherapy for the primary disease. Despite the efficacy of ensitrelvir in shortening the duration of symptoms, evidence of improved prognosis is lacking. However, prognosis might be improved if ensitrelvir treatment could reduce the viral load and shorten the time to postpone chemotherapy. It is unclear whether viral reduction directly improves prognosis. However, faster viral reduction may lead to faster resumption of chemotherapy for the underlying disease, resulting in better prognosis. Here, we present a case wherein we administered ensitrelvir fumaric acid to a 75-year-old woman with persistent COVID-19 after anti-CD20 antibody treatment. Her symptoms resolved quickly, with a reduction of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load, and she could continue receiving chemotherapy for lymphoma. Our findings suggest that ensitrelvir administration should be considered in patients with SARS-CoV-2 infection after anti-CD20 antibody treatment.

Microbial removal of nutrients from anaerobic digestate: assessing product-coupled and non-product-coupled approaches.

Although anaerobic digestate contains >90% water, the high nutrient content of digestate makes it economically and technically intractable to treatment by existing wastewater treatment technologies. This study separately assessed the feasibility of nutrient removal from digestate by Rhizopus delemar DSM 905 and a culture of phosphate-accumulating organisms (PAOs). With Rhizopus delemar DSM 905, we investigated concomitant nutrient removal from digestate-supplemented medium and fumaric acid production, as a potentially economical strategy for digestate treatment. Following the cultivation of R. delemar DSM 905 in a fermentation medium containing 25% (v/v) digestate, the concentrations of Al, Cr, Cu, Fe, K, Mg, Mn, Pb, and Zn reduced 40, 12, 74, 96, 12, 26, 23%, ~18, and 28%, respectively. Similarly, the concentrations of total phosphorus, total nitrogen, phosphate (PO4-P), ammonium (NH4-N), nitrate (NO3-N), and sulfur decreased 93, 88, 97, 98, 69, and 13%, respectively. Concomitantly, cultures supplemented with 25 and 15% (v/v) digestate produced comparable titers of fumarate (~11 and ~ 17 g/L, respectively) to the digestate un-supplemented control cultures. With PAOs, we assessed the removal of total phosphorus, total nitrogen, PO4-P, and NH4-N, of which the concentrations reduced 86, 90%, ~99, and 100%, respectively in 60% (v/v) digestate. This study provides additional bases for microbial removal of excess nutrients from anaerobic digestate, with the potential to engender future water recovery from this waste stream that is currently largely recalcitrant to treatment.

Thermal, morphology and bacterial analysis of pH-responsive sodium carboxyl methylcellulose/ fumaric acid/ acrylamide nanocomposite hydrogels: Synthesis and characterization.

In this present investigation, sodium carboxymethyl cellulose grafted with Fumaric acid/Acrylamide (CMC/FA/AAm=CFA) hydrogel and their silver nanocomposite hydrogels (CFA-Ag x, x = 5, 10 and 20) were developed by simple, cost effective and ecofriendly greener method. Mint leaf extract was used as an efficient natural reducing agent due to presence of active and antioxidant potential of polyphenol and flavonoid components. Swelling equilibrium of CFA hydrogel showed Seq% 3000 both in pH medium and distilled water. CFA (90:10) hydrogel has been produced greater than Seq% 6000. The synthesized CFA (90:10)-Ag-5, CFA (90:10)-Ag-10 and CFA (90:10)-Ag-20 nanocomposite hydrogels have been observed lower Seq% 2000-3000 than the CFA hydrogel. The homogeneous distribution of AgNPs throughout the CFA hydrogel and nanocomposites has been explored by SEM analysis. The interaction of network heteroatoms with AgNPs has been strongly revealed by the FTIR spectra and XRD analysis. The thermal stability of CFA (90:10)-Ag-5, 10, and 20 nanocomposite hydrogels have showed greater stability than CFA hydrogel which is confirmed by TGA/DSC thermogram analysis. The TEM analysis was used to explore a uniform distribution of spherical AgNPs (10 nm-50 nm) embedded on the CFA composite hydrogel. The CFA (90:10)-Ag-20 nanocomposite hydrogel has showed good antibacterial activity beside E. coli (Gram positive) and S. aureus (Gram negative) pathogens. Based on the antibacterial activity and swelling properties of CFA-Ag nanocomposite hydrogels have the ability to accelerate the antibacterial activity and are potential candidates for medical and environmental applications.

Effect of ethylenediaminetetraacetic acid, maleic acid, and fumaric acid on postendodontic treatment root fracture toughness - An in vitro study.

Aim: The aim of this study was to evaluate the effectiveness of ultrasonic activation of ethylenediaminetetraacetic acid (EDTA), maleic acid (MA), and fumaric acid (FA) in combination with sodium hypochlorite (NaOCl) on postendodontic treatment root fracture toughness. Materials and Methods: Forty single-rooted mandibular premolars were sectioned below the cementoenamel junction and were kept on average 14 mm long. With the exception of eight randomly selected teeth acting as a negative control group (Group I/nonprepared), the rest were prepared till F3. Thirty-two specimens were randomly placed into four groups equally and then irrigated using the final irrigation protocols. Saline and NaOCl were used to irrigate Group II, 17% EDTA and NaOCl were used to irrigate Group III, 7% MA and NaOCl were used to irrigate Group IV, and 0.7% FA and NaOCl were used to irrigate Group V. The irrigants were ultrasonically activated in every group. The root canals were obturated with gutta-percha and AH Plus sealer. The roots were embedded along the long axis in the self-curing acrylic blocks along with polyvinyl siloxane, leaving the coronal 2 mm of the root exposed. The specimens were tested using a universal testing machine. Statistical Analysis: The Post hoc Tamhane's and one-way ANOVA tests were applied to examine the data. Results: The result of the study revealed that 0.7% FA (598.09 N) provided better root fracture resistance than EDTA (428.07 N) and MA (511.87 N). Conclusion: The conclusion derived from the study was that 0.7% FA provided better fracture resistance of endodontically treated teeth when compared to 17% EDTA and 7% MA.

Post-Thaw Parameters of Buck Semen Quality after Soy Lecithin Extender Supplementation with Fumaric Acid.

The supplementation of cryopreservation media with antioxidants improves the post-thaw quality and fertilizing ability of spermatozoa. To maximize the fertility of frozen-thawed buck spermatozoa, further research is required to overcome obstacles that have yielded controversial results and standardize protocols. In the present work, the effect of adding fumaric acid (a well-described antioxidant) to a soy lecithin semen extender on certain quality parameters of spermatozoa following freezing and thawing was examined for the first time. Five sexually mature Skopelos bucks were used, and ejaculates were collected with an artificial vagina. The semen samples (98 samples, five replicates) were diluted (400 × 106 spermatozoa/mL) with OviXcell®, supplemented with fumaric acid (0 mM, 2.15 mM, 10 mM or 30 mM), equilibrated (5 °C; 3 h), packed (0.5 mL straws), frozen and stored (-196 °C) until further processing. After thawing, the spermatozoa total and progressive motility (CASA), viability (eosin-nigrosin), membrane functional integrity (HOST), acrosome integrity (SpermBlue®) and mitochondrial function (Rhodamine-123/SYBR-14/PI) were evaluated. Statistical analysis was performed with one-way ANOVA, followed by Duncan's test; significance was set at 0.05. The addition of 2.15 mM fumaric acid improved (p < 0.05) spermatozoa viability, membrane functional integrity, acrosome integrity and mitochondrial function compared to all other concentrations. The addition of 30 mM fumaric acid decreased (p < 0.05) spermatozoa viability and mitochondrial function compared to all other concentrations. These results indicate a beneficial effect of a 2.15 mM fumaric acid addition to a soy lecithin extender on post-thaw buck spermatozoa quality. Further research is required to evaluate the in vivo fertility of frozen-thawed buck spermatozoa treated with fumaric acid, as well as to elucidate the mechanism of action of fumaric acid in spermatozoa.

Promising Markers of Inflammatory and Gut Dysbiosis in Patients with Post-COVID-19 Syndrome.

Post-COVID-19 syndrome is a complex of different symptoms, which results in a multisystemic impairment after the suffering from COVID-19 infection. The aim of the study was to reveal the clinical, laboratory, and gut disorders in patients with post-COVID-19 syndrome (n = 39) before and after taking part in the 14-day complex program of rehabilitation. A complete blood count, coagulation test, blood chemistry, biomarkers, and metabolites in serum samples, and gut dysbiosis were revealed in patients on the day of admission and after 14-day rehabilitation, in comparison with the variables of healthy volunteers (n = 48) or with reference ranges. On the day of discharge, patients noted an improvement in respiratory function, general well-being, and mood. At the same time, the levels of some metabolic (4-hydroxybenzoic, succinic, fumaric acids) and inflammatory (interleukin-6) variables, which were increased on admission, did not reach the level of healthy people during the rehabilitation program. Taxonomy disbalance was observed in patients' feces, namely, a high level of total bacterial mass, a decrease in the number of Lactobacillus spp., and an increase in pro-inflammatory microorganisms. The authors suggest that the post-COVID-19 rehabilitation program should be personalized, considering the patient's state together with not only the baseline levels of biomarkers, but also with the individual taxonomy of the gut microbiota.

Cocrystals by Design: A Rational Coformer Selection Approach for Tackling the API Problems.

Active pharmaceutical ingredients (API) with unfavorable physicochemical properties and stability present a significant challenge during their processing into final dosage forms. Cocrystallization of such APIs with suitable coformers is an efficient approach to mitigate the solubility and stability concerns. A considerable number of cocrystal-based products are currently being marketed and show an upward trend. However, to improve the API properties by cocrystallization, coformer selection plays a paramount role. Selection of suitable coformers not only improves the drug's physicochemical properties but also improves the therapeutic effectiveness and reduces side effects. Numerous coformers have been used till date to prepare pharmaceutically acceptable cocrystals. The carboxylic acid-based coformers, such as fumaric acid, oxalic acid, succinic acid, and citric acid, are the most commonly used coformers in the currently marketed cocrystal-based products. Carboxylic acid-based coformers are capable of forming the hydrogen bond and contain smaller carbon chain with the APIs. This review summarizes the role of coformers in improving the physicochemical and pharmaceutical properties of APIs, and deeply explains the utility of afore-mentioned coformers in API cocrystal formation. The review concludes with a brief discussion on the patentability and regulatory issues related to pharmaceutical cocrystals.

Short-chain fatty acids reprogram metabolic profiles with the induction of reactive oxygen species production in human colorectal adenocarcinoma cells.

Short-chain fatty acids (SCFAs) exhibit anticancer activity in cellular and animal models of colon cancer. Acetate, propionate, and butyrate are the three major SCFAs produced from dietary fiber by gut microbiota fermentation and have beneficial effects on human health. Most previous studies on the antitumor mechanisms of SCFAs have focused on specific metabolites or genes involved in antitumor pathways, such as reactive oxygen species (ROS) biosynthesis. In this study, we performed a systematic and unbiased analysis of the effects of acetate, propionate, and butyrate on ROS levels and metabolic and transcriptomic signatures at physiological concentrations in human colorectal adenocarcinoma cells. We observed significantly elevated levels of ROS in the treated cells. Furthermore, significantly regulated signatures were involved in overlapping pathways at metabolic and transcriptomic levels, including ROS response and metabolism, fatty acid transport and metabolism, glucose response and metabolism, mitochondrial transport and respiratory chain complex, one-carbon metabolism, amino acid transport and metabolism, and glutaminolysis, which are directly or indirectly linked to ROS production. Additionally, metabolic and transcriptomic regulation occurred in a SCFAs types-dependent manner, with an increasing degree from acetate to propionate and then to butyrate. This study provides a comprehensive analysis of how SCFAs induce ROS production and modulate metabolic and transcriptomic levels in colon cancer cells, which is vital for understanding the mechanisms of the effects of SCFAs on antitumor activity in colon cancer.

Pectin Extraction from Residues of the Cocoa Fruit (Theobroma cacao L.) by Different Organic Acids: A Comparative Study.

Ecuador is the world's fifth largest cocoa producer, generating hundreds of tons of residues from this fruit annually. This research generates value from the residual (cocoa pod husk) by using it as raw material to obtain pectin, which is widely used in the food and pharmaceutical industries. Extraction of three different organic acids with GRAS status (safe for use), the citric, malic and fumaric acids, was studied. In addition, two other factors, temperature (70-90 °C) and extraction time (60-90 min), were explored in a central composite design of experiments. We determined the conditions of the experiments where the best yields were garnered for citric acid, malic acid and fumaric acid, along with a ~86 min extraction time. The temperature did not show a significant influence on the yield. The pectin obtained under optimal conditions was characterised, showing the similarity with commercial pectin. However, the equivalent weight and esterification degree of the pectin obtained with fumaric acid led us to classify it as having a high equivalent weight and a low degree of esterification. In these regards, it differed significantly from the other two acids, perhaps due to the limited solubility of fumaric acid.

Constructing recombinant Saccharomyces cerevisiae strains for malic-to-fumaric acid conversion.

Saccharomyces cerevisiae with its robustness and good acid tolerance, is an attractive candidate for use in various industries, including waste-based biorefineries where a high-value organic acid is produced, such as fumaric acid could be beneficial. However, this yeast is not a natural producer of dicarboxylic acids, and genetic engineering of S. cerevisiae strains is required to achieve this outcome. Disruption of the natural FUM1 gene and the recombinant expression of fumarase and malate transporter genes improved the malic acid-to-fumaric acid conversion by engineered S. cerevisiae strains. The efficacy of the strains was significantly influenced by the source of the fumarase gene (yeast versus bacterial), the presence of the XYNSEC signal secretion signal and the available oxygen in synthetic media cultivations. The ΔFUM1Ckr_fum + mae1 and ΔFUM1(ss)Ckr_fum + mae1 strains converted extracellular malic acid into 0.98 and 1.11 g/L fumaric acid under aerobic conditions.

The Antineoplastic Effect of Dimethyl Fumarate on Virus-Negative Merkel Cell Carcinoma Cell Lines: Preliminary Results.

Merkel cell carcinoma (MCC) is a rare, difficult-to-treat skin cancer once immunotherapy has failed. MCC is associated either with the clonal integration of the Merkel cell polyomavirus (MCPyV) or mutagenic UV-radiation. Fumaric acid esters, including dimethyl fumarate (DMF), have been shown to inhibit cell growth in cutaneous melanoma and lymphoma. We aimed to explore the effects of DMF on MCPyV-negative MCC cell lines. Three MCC cell lines (MCC13, MCC14.2, and MCC26) were treated with different doses of DMF. The cytotoxic effects and cell proliferation were assessed by the MTT cytotoxicity assay and BrdU proliferation assay at different time points. A significant reduction in cell viability and proliferation were demonstrated for all the cell lines used, with DMF proving to be effective.

Recent advances and perspectives on production of value-added organic acids through metabolic engineering.

Organic acids are important consumable materials with a wide range of applications in the food, biopolymer and chemical industries. The global consumer organic acids market is estimated to increase to $36.86 billion by 2026. Conventionally, organic acids are produced from the chemical catalysis process with petrochemicals as raw materials, which posts severe environmental concerns and conflicts with our sustainable development goals. Most of the commonly used organic acids can be produced from various organisms. As a state-of-the-art technology, large-scale fermentative production of important organic acids with genetically-modified microbes has become an alternative to the chemical route to meet the market demand. Despite the fact that bio-based organic acid production from renewable cheap feedstock provides a viable solution, low productivity has impeded their industrial-scale application. With our deeper understanding of strain genetics, physiology and the availability of strain engineering tools, new technologies including synthetic biology, various metabolic engineering strategies, omics-based system biology tools, and high throughput screening methods are gradually established to bridge our knowledge gap. And they were further applied to modify the cellular reaction networks of potential microbial hosts and improve the strain performance, which facilitated the commercialization of consumable organic acids. Here we present the recent advances of metabolic engineering strategies to improve the production of important organic acids including fumaric acid, citric acid, itaconic acid, adipic acid, muconic acid, and we also discuss the current challenges and future perspectives on how we can develop a cost-efficient, green and sustainable process to produce these important chemicals from low-cost feedstocks.

The ornithine-urea cycle involves fumaric acid biosynthesis in Aureobasidium pullulans var. aubasidani, a green and eco-friendly process for fumaric acid production.

The current petroleum chemical methods for fumaric acid production can cause heavy pollution and global warming. In this study, the engineered strains of A. pullulans var. aubasidani were found to be suitable for green fumaric acid producer. Removal and complementation of the relevant genes showed only the ornithine-urea cycle (OUC) was involved in high level fumarate biosynthesis which was controlled by the Ca2+ signaling pathway. Removal of both the GOX gene encoding glucose oxidase and the PKS1 gene encoding the polyketide synthase for 3,5-dihydroxydecanoic acid biosynthesis and overexpression of the PYC gene encoding pyruvate carboxylase made the strain e-PYC produce 88.1 ± 4.3 g/L of fumarate at flask level and 93.9 ± 0.8 g/L of fumarate during the fed-batch fermentation. As a yeast-like fungal strain, it was very easy to cultivate A. pullulans var. aubasidani DH177 and their mutants in the bioreactor and to edit its genomic DNAs to enhance fumarate production. It was found that 2 mol of CO2 could be fixed during a maximal theoretical yield of 2 mol of fumarate per mole of glucose consumed in the OUC. Therefore, the OUC-mediated fumarate biosynthesis pathway in A. pullulans var. aubasidani was a green and eco-friendly process for the global sustainable development and carbon neutrality.