Utilizing rice straw and sugarcane bagasse as low-cost feedstocks towards sustainable production of succinic acid.

Succinic acid (SA) has been produced from rice straw (RS) and sugarcane bagasse (SB) as low-cost feedstocks in this study through sequential peracetic acid (PA) and alkaline peroxide (AP) pretreatment assisted by ultrasound and pre-hydrolysis followed by simultaneous saccharification and fermentation (PSSF). The effect of yeast extract (YE) concentration, inoculum concentration, and biomass type on SA production was investigated. The results showed that SA production from RS and SB was significantly affected by the YE concentration. Final concentration and yield of SA produced were significantly increased along with the increasing of YE concentration. Moreover, inoculum concentration significantly affected the SA production from SB. Higher inoculum concentration led to higher SA production. On the other hand, SA production from RS was not significantly affected by the inoculum concentration. Using RS as the feedstock, the highest SA production was achieved on the medium containing 15 g/L YE with 5 % v/v inoculum, obtaining SA concentration and yield of 3.64 ± 0.1 g/L and 0.18 ± 0.05 g/g biomass, respectively. Meanwhile, the highest SA production from SB was acquired on the medium containing 10 g/L YE with 7.5 % v/v inoculum, resulting SA concentration and yield of 5.1 ± 0.1 g/L and 0.25 ± 0.05 g/g biomass, respectively. This study suggested that RS and SB are potential to be used as low-cost feedstocks for sustainable and environmentally friendly SA production through ultrasonic-assisted PA and AP pretreatment and PSSF.

Assessment of vine shoots and surplus grape must for succinic acid bioproduction.

Vine shoots and surplus grape must were assessed as feedstocks for succinic acid production with Actinobacillus succinogenes and Basfia succiniproducens. After acidic and enzymatic hydrolysis, vine shoots released 35-40 g/L total sugars. Both bacterial species produced 18-21 g/L succinic acid from this hydrolysate in 120 h. Regarding grape must fermentation, A. succinogenes clearly outperformed B. succiniproducens. Yeast extract (a source of organic nitrogen and vitamins) was the only additional nutrient needed by A. succinogenes to grow on grape must. Under mathematically optimized conditions (145.7 g/L initial sugars and 24.9 g/L yeast extract), A. succinogenes generated 88.9 ± 1.4 g/L succinic acid in 96 h, reaching a succinic acid yield of 0.66 ± 0.01 g/g and a sugar consumption of 96.64 ± 0.30%. Substrate inhibition was not observed in grape musts with 125-150 g/L initial sugars, provided that an adequate amount of yeast extract was available for bacteria. Alternative nitrogen sources to yeast extract (red wine lees, white wine lees, urea, NH4Cl, and choline chloride) were not suitable for A. succinogenes in grape must. KEY POINTS: • Vine shoots and surplus grape must were assessed for succinic acid bioproduction. • Succinic acid bioproduction was 21 g/L with vine shoots and 89 g/L with grape must. • Fermentation was efficient at high sugar loads if organic N supply was adequate.

Biorefinery development, techno-economic evaluation and environmental impact analysis for the conversion of the organic fraction of municipal solid waste into succinic acid and value-added fractions.

The organic fraction of municipal solid waste (OFMSW) was used for biorefinery development within a circular bioeconomy context towards extraction of lipids/fats and proteins with 100% and 68% recovery yields, respectively, as well as succinic acid (SA) production. A nutrient-rich hydrolysate (89.1 g/L sugars) produced using crude enzymes derived via solid state fermentation of Aspergillus awamori, was employed in Actinobacillus succinogenes fermentation leading to 31.7 gSA/L with 0.68 g/g yield and 0.67 g/L/h productivity. The SA minimum selling price ($1.13-2.39/kgSA) considering 60,000 tSA/year production varied depending on co-product market prices and OFMSW management fees. The biorefinery using 1000 kg OFMSW contributes 35% lower CO2 emissions than conventional processes for the production of 105 kg vegetable oil, 87 kg vegetable protein and 206.4 kg fossil-SA considering also the CO2 emissions due to OFMSW landfilling. The proposed OFMSW biorefinery leads to cost-competitive SA production with lower CO2 emissions for OFMSW treatment.

Low cost nutrient-rich oil palm trunk bagasse hydrolysate for bio-succinic acid production by Actinobacillus succinogenes.

Economical source of succinic acid (SA) is most sought-after as a key platform chemical for a wide range of applications. Low-cost production of bio-succinic acid (bio-SA) from a renewable biomass resource i.e., oil palm trunk (OPT) is reported in this paper. Apart from carbon source, nitrogen source and mineral salts are other important nutrients affecting microbial cell growth and bio-SA biosynthesis by Actinobacillus succinogenes 130Z. In order to access and optimize nutrient requirement of the latter two sources, their effects in terms of types and concentrations were investigated. The findings highlighted the importance of selecting proper nitrogen source in A. succinogenes fermentation. The possibility of producing bio-SA from OPT economically can be achieved through minimal supply of 5 g/L yeast extract compared to that generally supplemented 15 g/L with a similar yield (0.47 g/g). In addition, a higher bio-SA yield (0.49 g/g) was achieved without adding mineral salts, which could further reduce fermentation cost. The use of minimally supplemented hydrolysate resulted in 21.1 g/L of bio-SA with a satisfactory yield (0.58 g/g) in a batch bioreactor system with an estimated 56.4% in cost savings. Conclusively, OPT bagasse hydrolysate is a nutrient-rich feedstock that can be practically utilized for bio-SA production.

Techno-economic evaluation and life cycle assessment of a biorefinery using winery waste streams for the production of succinic acid and value-added co-products.

This study presents techno-economic evaluation and life cycle assessment of a novel biorefinery using the three main waste streams generated by wineries for the production of bio-based succinic acid (SA), crude phenolic-rich extract, grape-seed oil, calcium tartrate and crude tannin-rich extract. Process design has been employed for the estimation of material and energy balances and the sizing of unit operations. The Minimum Selling Price of succinic acid production within a winery waste biorefinery ranges from $1.23-2.76/kgSA depending on the market price and the potential end-uses of the extracted fractions. The Global Warming Potential and the Abiotic Depletion Potential of winery waste valorisation through the proposed biorefinery are 1.47 kg CO2-eq per kg dry waste and 25.2 MJ per kg dry waste, respectively. Biorefining of winery waste could lead to the development of a sustainable and novel bioeconomy business model with new market opportunities and efficient waste management.

Resistance risk assessment for a novel succinate dehydrogenase inhibitor pydiflumetofen in Fusarium asiaticum.

BACKGROUND: Fusarium asiaticum is one of predominant pathogens of Fusarium head blight (FHB) in China. Pydiflumetofen (Pyd) is a novel succinate dehydrogenase inhibitor (SDHI) which has been commercialized in China for the controlling of wheat FHB since 2019. In the current study, a risk assessment of the pydiflumetofen-resistance selected in Fusarium asiaticum was investigated. RESULTS: One PydMR mutant [resistance factor (RF) < 80] and four PydHR mutants (RF > 3000) were generated by fungicide-taming from 1000 mycelial discs of the wild-type strain 2021. Nucleotide sequences alignment results of FaSdh from the wild-type strain and resistant mutants showed that all the mutations were categorized into three genotypes, i.e. FaSdhBH248Y from PydMR mutant, both FaSdhC1 A64V and FaSdhC1 R67K from PydHR mutants. All the resistant mutants possessed no fitness penalty based on the data of mycelial linear growth, conidiation and virulence. In addition, the FaSdhC1 A64V mutants showed positive cross-resistance between pydiflumetofen and boscalid or thifluzamide, but no cross-resistance between pydiflumetofen and Y13149 or Y12196, while the FaSdhC1 R67K mutants exhibited positive cross-resistance between pydiflumetofen and boscalid, thifluzamide or Y12196, and no cross-resistance between pydiflumetofen and Y13149. Furthermore, positive cross-resistance between the five tested SDHIs was detected in the FaSdhBH248Y mutants. CONCLUSION: The results suggest a moderate to high resistance risk of F. asiaticum to pydiflumetofen, and provide essential data for monitoring the emergence of resistance and resistance management strategies for pydiflumetofen, which will be useful for scientific application of this fungicide in China.

Sustainable production of bio-based chemicals and polymers via integrated biomass refining and bioprocessing in a circular bioeconomy context.

The sustainable production of bio-based chemicals and polymers is highly dependent on the development of viable biorefinery concepts using crude renewable resources for the production of diversified products. Within this concept, this critical review presents the availability of fractionated co-products and fermentable sugars that could be derived from major industrial and food supply chain side streams in EU countries. Fermentable sugars could be used for the production of bio-based chemicals and polymers. The implementation of biorefinery concepts in industry should depend on the evaluation of process efficiency and sustainability including techno-economic, environmental and social impact assessment following circular bioeconomy principles. Relevant sustainability indicators and End-of-Life scenarios have been presented. A case study on the techno-economic evaluation of bio-based succinic acid production from the organic fraction of municipal solid waste has been presented focusing on the evaluation of process profitability and feedstock requirements.

Disparity of Cytochrome Utilization in Anodic and Cathodic Extracellular Electron Transfer Pathways of Geobacter sulfurreducens Biofilms.

Extracellular electron transfer (EET) in microorganisms is prevalent in nature and has been utilized in functional bioelectrochemical systems. EET of Geobacter sulfurreducens has been extensively studied and has been revealed to be facilitated through c-type cytochromes, which mediate charge between the electrode and G. sulfurreducens in anodic mode. However, the EET pathway of cathodic conversion of fumarate to succinate is still under debate. Here, we apply a variety of analytical methods, including electrochemistry, UV-vis absorption and resonance Raman spectroscopy, quartz crystal microbalance with dissipation, and electron microscopy, to understand the involvement of cytochromes and other possible electron-mediating species in the switching between anodic and cathodic reaction modes. By switching the applied bias for a G. sulfurreducens biofilm coupled to investigating the quantity and function of cytochromes, as well as the emergence of Fe-containing particles on the cell membrane, we provide evidence of a diminished role of cytochromes in cathodic EET. This work sheds light on the mechanisms of G. sulfurreducens biofilm growth and suggests the possible existence of a nonheme, iron-involving EET process in cathodic mode.

Resistance risk assessment for Fusarium graminearum to pydiflumetofen, a new succinate dehydrogenase inhibitor.

BACKGROUND: Pydiflumetofen is a new generation succinate dehydrogenase inhibitor currently undergoing the process of registration in China for the control of Fusarium head blight in wheat. A resistance risk assessment of Fusarium graminearum to pydiflumetofen was undertaken in this study. RESULTS: A total of 75 pydiflumetofen-resistant mutants were generated through spontaneous selection and displayed high resistance with an average resistance factor (RF) value of 78. Four mutants were generated through UV mutagenesis and displayed very high resistance with an RF value >1000. The sequence analysis results for Sdh genes and fitness studies revealed the existence of four types of mutations. In particular, 32 spontaneous selection mutants (SP mutants) had an arginine (R) to histidine (H) transition at position 86 in FGSdhC, resulting in seriously reduced fitness. Seven SP mutants had an R to cysteine (C) transition at position 86 in FGSdhC, resulting in reduced fitness. Thirty-six SP mutants had an alanine (A) to valine (V) transition at position 83 in FGSdhC and had no fitness penalties. The efficacy of pydiflumetofen towards a mutant carrying A83V in FGSdhC in vivo was significantly decreased at 42.7%. Four UV mutants had no mutations on all Sdh genes and no fitness penalties. Cross-resistance among boscalid, fluopyram and pydiflumetofen was observed. CONCLUSION: Sdhc mutations were found and other target site resistance may be present in laboratory PR mutants of F. graminearum. An overall moderate risk of resistance development in F. graminearum was recommended for pydiflumetofen. © 2019 Society of Chemical Industry.

Two for the price of one: Attacking the energetic-metabolic hub of mycobacteria to produce new chemotherapeutic agents.

Cellular bioenergetics is an area showing promise for the development of new antimicrobials, antimalarials and cancer therapy. Enzymes involved in central carbon metabolism and energy generation are essential mediators of bacterial physiology, persistence and pathogenicity, lending themselves natural interest for drug discovery. In particular, succinate and malate are two major focal points in both the central carbon metabolism and the respiratory chain of Mycobacterium tuberculosis. Both serve as direct links between the citric acid cycle and the respiratory chain due to the quinone-linked reactions of succinate dehydrogenase, fumarate reductase and malate:quinone oxidoreductase. Inhibitors against these enzymes therefore hold the promise of disrupting two distinct, but essential, cellular processes at the same time. In this review, we discuss the roles and unique adaptations of these enzymes and critically evaluate the role that future inhibitors of these complexes could play in the bioenergetics target space.

Succinylated Jeffamine ED-2003 coated polycarbonate chips for low-cost analytical microarrays.

Analytical microarrays feature great capabilities for simultaneous detection and quantification of multiple analytes in a single measurement. In this work, we present a rapid and simple method for bulk preparation of microarrays on polycarbonate sheets. Succinylated Jeffamine® ED-2003 was screen printed on polycarbonate sheets to create a polyfunctional shielding layer by baking at 100 °C. After microdispension of capture probes (antibodies, oligonucleotides, or small molecules) in a microarray format, chips were assembled with a flow cell from double-sided tape. It was shown that the shielding layer was firmly coated and suppressed unspecific binding of proteins. Universal applicability was demonstrated by transferring established flow-based chemiluminescence microarray measurement principles from glass slides to polycarbonate chips without loss of analytical performance. Higher chemiluminescence signals could be generated by performing heterogeneous asymmetric recombinase polymerase amplification on polycarbonate chips. Similar results could be shown for sandwich microarray immunoassays. Beyond that, lower inter- and intra-assay variances could be measured for the analysis of Legionella pneumophila Serogroup 1, strain Bellingham-1. Even surface regeneration of indirect competitive immunoassays was possible, achieving a limit of detection of 0.35 ng L-1 for enrofloxacin with polycarbonate microarray chips. Succinylated Jeffamine ED-2003 coated polycarbonate chips have great potential to replace microtiter plates by flow-based chemiluminescence microarrays for rapid analysis. Therefore, it helps analytical microarrays to advance into routine analysis and diagnostics. Graphical abstract ᅟ.

Large-Scale Assessment of Bioinformatics Tools for Lysine Succinylation Sites.

Lysine succinylation is a form of posttranslational modification of the proteins that play an essential functional role in every aspect of cell metabolism in both prokaryotes and eukaryotes. Aside from experimental identification of succinylation sites, there has been an intense effort geared towards the development of sequence-based prediction through machine learning, due to its promising and essential properties of being highly accurate, robust and cost-effective. In spite of these advantages, there are several problems that are in need of attention in the design and development of succinylation site predictors. Notwithstanding of many studies on the employment of machine learning approaches, few articles have examined this bioinformatics field in a systematic manner. Thus, we review the advancements regarding the current state-of-the-art prediction models, datasets, and online resources and illustrate the challenges and limitations to present a useful guideline for developing powerful succinylation site prediction tools.

Continuous Succinic Acid Fermentation by Actinobacillus Succinogenes: Assessment of Growth and Succinic Acid Production Kinetics.

Succinic acid is one of the most interesting platform chemicals that can be produced in a biorefinery approach. The paper reports the characterization of the growth kinetics of Actinobacillus succinogenes DSM 22257 using glucose as carbon source. Tests were carried out in a continuous bioreactor operated under controlled pH. Under steady-state conditions, the conversion process was characterized in terms of concentration of glucose, cells, acids, and pH. The effects of acid-succinic, acetic, and formic-concentration in the medium on fermentation performance were investigated. The fermentation was interpreted according to several models characterized by substrate and product inhibition. The selected kinetic model of biomass growth and of metabolite production described the microorganism growth rate under a broad interval of operating conditions. Under the investigated operating conditions, results pointed out that: no substrate inhibition was observed; acetic acid did not inhibit the cell growth and succinic acid production.

Life cycle assessment of a bioelectrochemical system as a new technological platform for biosuccinic acid production from waste.

Waste management is a key environmental and socio-economic issue. Environmental concerns are encouraging the use of alternative resources and lower emissions to air, water and soil. Innovative technologies to deal with waste recovery that produce marketable bioproducts are emerging. Bioelectrochemical synthesis systems (BESs) are based on the primary principle of transforming organic waste into added-value products using microorganisms to catalyse chemical reactions. This technology is at the core of a research project called BIORARE (BIoelectrosynthesis for ORganic wAste bioREfinery), an interdisciplinary project that aims to use anaerobic digestion as a supply chain to feed a BES and produce target biomolecules. This technology needs to be driven by environmental strategies. Life Cycle Assessment (LCA) was used to evaluate the BIORARE concept based on expert opinion and prior experiments for the production of biosuccinic acid and waste management. A multidisciplinary approach based on biochemistry and process engineering expertise was used to collect the inventory data. The BES design and the two-step anaerobic digestion process have many potential impacts on air pollution or ecotoxicity-related categories. The comparison of the BIORARE concept with conventional fermentation processes and a water-fed BES technology demonstrated the environmental benefit resulting from the use of both the BES technology and a waste-based substrate as input thus supporting the BIORARE concept. Some trade-offs among the impact categories were identified but led to options to improve the concept. BES design and synergy management may improve the environmental performance of the BIORARE concept.

Assessment of alterations in X-ray irradiation-induced DNA damage of glioma cells by using proton nuclear magnetic resonance spectroscopy.

Glioma is one of the most common types of brain tumors. DNA damage is closely associated with glioma cell apoptosis induced by X-ray irradiation. Alterations of metabolites in glioma can be detected noninvasively by proton nuclear magnetic resonance (1H NMR) spectroscopy. To noninvasively explore the micro mechanism in X-ray irradiation-induced apoptosis, the relationship between metabolites and DNA damage in glioma cells was investigated. Three glioma cell lines (C6, U87 and U251) were randomly designated as control (0Gy) and treatment groups (1, 5, 10, 15Gy). After X-ray exposure, each group was separated into four parts: (i) to detect metabolites by 1H NMR spectroscopy; (ii) to make cell colonies; (iii) to detect cell cycle distribution and apoptosis rate by flow cytometry; and (iv) to measure DNA damage by comet assay. The metabolite ratios of lactate/creatine and succinate/creatine decreased (lactate/creatine: C6, 22.17-66.27%; U87, 15.93-44.56%; U251, 26.27-74.48%. succinate/creatine: C6, 14.41-48.35%; U87, 22.03-70.62%; U251, 17.33-60.06%) and choline/creatine increased (C6, 52.22-389.68%; U87, 56.15-82.36%; U251, 31.87-278.62%) in the treatment groups compared with the control group (each P<0.05), which linearly depended on DNA damage. An increasing dose of X-ray irradiation increased numbers of apoptotic cells (P<0.01), and the DNA damage parameters were dose-dependent (P<0.05). The colony-forming rate declined (P<0.01) and the percentage of cells at G1 stage increased when exposed to 1Gy X-ray (three cell lines, P<0.05). Metabolite alterations detected by 1H NMR spectroscopy can be used to determine DNA damage induced by X-ray irradiation. 1H NMR spectroscopy is a noninvasive method to predict DNA damage of glioma cell at the micro level.

Improving succinic acid production by Actinobacillus succinogenes from raw industrial carob pods.

Carob pods are an inexpensive by-product of locust bean gum industry that can be used as renewable feedstock for bio-based succinic acid. Here, for the first time, unprocessed raw carob pods were used to extract a highly enriched sugar solution, afterwards used as substrate to produce succinic acid using Actinobacillus succinogenes. Batch fermentations containing 30g/L sugars resulted in a production rate of 1.67gSA/L.h and a yield of 0.39gSA/g sugars. Taking advantage of A. succinogenes' metabolism, uncoupling cell growth from succinic acid production, a fed-batch mode was implemented to increase succinic acid yield and reduce by-products formation. This strategy resulted in a succinic acid yield of 0.94gSA/g sugars, the highest yield reported in the literature for fed-batch and continuous experiments, while maintaining by-products at residual values. Results demonstrate that raw carob pods are a highly efficient feedstock for bio-based succinic acid production.

[Current status of bio-based materials industry in China].

In recent years, bio-based materials are becoming a new dominant industry leading the scientific and technological innovation, and economic development of the world. We reviewed the new development of bio-based materials industry in China, analyzed the entire market of bio-based materials products comprehensively, and also stated the industry status of bio-based chemicals, such as lactic acid, 1,3-propanediol, and succinic acid; biodegradable bio-based polymers, such as co-polyester of diacid and diol, polylactic acid, carbon dioxide based copolymer, polyhydroxyalknoates, polycaprolactone, and thermoplastic bio-based plastics; non-biodegradable bio-based polymers, such as bio-based polyamide, polytrimethylene terephthalate, bio-based polyurethane, and bio-based fibers.

EXPERIMENTAL ASSESSMENT OF THE SPECIFIC EFFICIENCY OF NEW METABOLIC DRUG RUNIKHOL ON MODELS OF NON-ALCOHOLIC FATTY LIVER DISEASE.

We present results of preclinical evaluation of the specific efficiency of new metabolic corrector runikhol on models of non-alcoholic fatty liver disease in laboratory rats (228 albino males of gray Wistar rats weighing 220 - 240 g). The drug based on succinic acid positively influences the key types of metabolism impaired under conditions of development of the metabolic syndrome. Results of research testify to high efficiency and good prospects of using runikhol in the treatment of metabolic syndrome accompanied by organ disorders.

Economically enhanced succinic acid fermentation from cassava bagasse hydrolysate using Corynebacterium glutamicum immobilized in porous polyurethane filler.

An immobilized fermentation system, using cassava bagasse hydrolysate (CBH) and mixed alkalis, was developed to achieve economical succinic acid production by Corynebacterium glutamicum. The C. glutamicum strains were immobilized in porous polyurethane filler (PPF). CBH was used efficiently as a carbon source instead of more expensive glucose. Moreover, as a novel method for regulating pH, the easily decomposing NaHCO3 was replaced by mixed alkalis (NaOH and Mg(OH)2) for succinic acid production by C. glutamicum. Using CBH and mixed alkalis in the immobilized batch fermentation system, succinic acid productivity of 0.42gL(-1)h(-1) was obtained from 35gL(-1) glucose of CBH, which is similar to that obtained with conventional free-cell fermentation with glucose and NaHCO3. In repeated batch fermentation, an average of 22.5gL(-1) succinic acid could be obtained from each batch, which demonstrated the enhanced stability of the immobilized C. glutamicum cells.

Health impact assessment of decreases in PM10 and ozone concentrations in the Mexico City Metropolitan Area: A basis for a new air quality management program / Evaluación de impacto en salud ante reducciones de PM10 y ozono en la Zona Metropolitana del Valle de México: Base para un nuevo programa de calidad del aire

Objective. To conduct a health impact assessment (HIA) to quantify health benefits for several PM and O3 air pollution reduction scenarios in the Mexico City Metropolitan Area (MCMA). Results from this HIA will contribute to the scientific support of the MCMA air quality management plan (PROAIRE) for the period 2011-2020. Materials and methods. The HIA methodology consisted of four steps: 1) selection of the air pollution reduction scenarios, 2) identification of the at-risk population and health outcomes for the 2005 baseline scenario, 3) selection of concentration-response functions and 4) estimation of health impacts. Results. Reductions of PM10 levels to 20 μg/m³ and O3 levels to 0.050ppm (98 µg/m³) would prevent 2300 and 400 annual deaths respectively. The greatest health impact was seen in the over-65 age group and in mortality due to cardiopulmonary and cardiovascular disease. Conclusion. Improved air quality in the MCMA could provide significant health benefits through focusing interventions by exposure zones.

Objetivo. Realizar una evaluación de impacto en salud (EIS) que documente los beneficios en salud ante diversos escenarios de reducción de PM10 y O3 en el aire de la Zona Metropolitana del Valle de México (ZMVM). Los resultados contribuyen al sustento científico del plan de gestión de calidad del aire (PROAIRE 2011-2020). Material y métodos. La metodología de EIS comprende cuatro pasos: 1) selección de los escenarios de reducción, 2) identificación de la población en riesgo y de los eventos en salud para el año basal 2005, 3) selección de las funciones de concentración-respuesta y 4) estimación del impacto en la salud. Resultados. Reducciones de PM10 a 20μg/m³ y de O3 a 0.050ppm (98 µg/m³) evitarían, respectivamente, cerca de 2 300 y 400 muertes por año. El mayor impacto se observa en el grupo de más de 65 años y en la mortalidad por causas cardiopulmonares y cardiovasculares. Conclusiones. Mejorar la calidad del aire en la ZMVM podría reflejar importantes beneficios para la salud focalizados por zonas o áreas de exposición.