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Converting woody biomass to bioethanol might be more affordable, environmentally friendly, and efficient for making biofuel commercially feasible, but it would still need a significant optimization process and expand pilot-scale research. A combination of commercial low enzymes loading at 10 FPU/g glucan and compound additives utilizing Tween 80, PEG8000 and sophorolipid applied from lab-scale to pilot-scale have been studied in this work at economically viable dosages for enhancing bioethanol production. In lab-scale saccharification and fermentation, pretreated poplar at a high solid loading of 20% yielded the highest ethanol titers of 30.96 g/L and theoretical ethanol yield of 92.79%. Additionally, pilot-scale operation was used to investigate the bioethanol amplification, a final volume of 33 m3 which yielded the greatest ethanol amount of 599.6 kg from poplar wood while gaining on-site value-added production of hemicellulosic and cellobiose liquor 1122 kg and lignin residues 2292 kg.
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Tensoactivos , Madera , Biomasa , Madera/metabolismo , Fermentación , Lignina/química , Etanol , HidrólisisRESUMEN
SCOPE: Gamma-aminobutyric acid (GABA) represents positive effects in stress model, but the exact antioxidant remains unclear. This study aims to determine what GABA do and how GABA interfere on oxidative stress in the small intestine of radiation-induced intestinal injury (RIII) mice. METHODS AND RESULTS: C57BL/6J mice are gavaged. (1) Investigating the effects of GABA (50 100 mg kg-1 BW d-1 ) on basic information of healthy mice, and the survival time of RIII mice. (2) Evaluating the effect between GABA and theanine (100 mg kg-1 BW d-1 ) to RIII mice on the small intestine, by observing jejunum pathology, oxidative stress in small intestine and its mitochondria, and apoptosis protein expression. GABA reduces the weight loss and prolongs the median survival time of RIII mice. GABA and theanine reduce liver hyperemia, protect the villus crypt of jejunum, increase the antioxidant of duodenum and its mitochondria, to maintain the normal function and morphology. Besides, GABA increases B-cell lymphoma-2 (Bcl-2) expression and inhibits Caspase-3 activation, thereby inhibiting mitochondria-induced apoptosis. CONCLUSION: GABA reduces the oxidative stress of small intestine in RIII mice, and maintains the normal morphology and function of mitochondria, which mechanism is that high Bcl-2 expression inhibits the autophagy of mitochondrial pathway, thus reducing intestinal barrier damage.
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Antioxidantes , Ácido gamma-Aminobutírico , Ratones , Animales , Antioxidantes/farmacología , Antioxidantes/metabolismo , Ratones Endogámicos C57BL , Ácido gamma-Aminobutírico/farmacología , Ácido gamma-Aminobutírico/metabolismo , Intestino Delgado , Mucosa Intestinal/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/genética , Proteínas Proto-Oncogénicas c-bcl-2/metabolismoRESUMEN
Compound oral liquid (COL), made from functional herbal foods, has gained immense popularity in China for healthcare. However, the interaction between the nutrients in COL and gut microbiota is still unclear. In our study, the content of total flavonoids, polyphenols, and proteins was increased and the total sugar reduced by crushing raw ingredients to 10 mesh (COL-C). After 24 h incubation with supplemented COL by human gut microbiota, the results of 16S rRNA high-throughput sequencing revealed that Faecalibacterium, Collinsella, Bifidobacterium, Megamonas, Lactobacillus, Phascolarctobacterium, and Dialister were enriched by COL. In particular, the latter three genera were observed to be significantly enriched after incubation with COL-C. Meanwhile, the abundance of Dorea, Clostridium XIVa, and Escherichia/Shigella was inhibited by COL. Moreover, the increased levels of acetate, propionate, and butyrate in COL were jointly contributed by supplementary carbohydrates and the enrichment of short-chain fatty acid (SCFA)-producing bacteria. In summary, our results indicated that the optimized extraction facilitated the nutrients to be dissolved out and enhanced the potential prebiotic effects for promoting the abundance of probiotics, suggesting that the nutrients in COL-C might improve the microbial structure by strengthening the metabolism of beneficial bacteria and restricting the conditioned pathogens more efficiently.
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Extrusion improves the texture of wheat bran and enhances its product edibility, making it a promising processing method. However, the extrusion performance of wheat bran without any treatment is not satisfactory and limits the utilization of wheat bran in food processing. In this study, steam explosion pretreatment was used to treat wheat bran to investigate its promotion of wheat bran extrusion. The results showed that steam explosion could increase the extrusion ratio of wheat bran extrudate by 36%. Grinding the steam-exploded wheat bran extrudate yields wheat bran flour with smaller particle sizes and higher cell wall breakage. Fourier transform infrared spectroscopy and chemical composition results revealed that steam explosion degraded insoluble dietary fiber and disrupted the dense structure of the cell wall in wheat bran. The water-extracted arabinoxylan and soluble dietary fiber content of steam-exploded wheat bran were 13.95% and 7.47%, respectively, improved by 1567.42% and 241.75% compared to untreated samples. The total phenol and flavonoid contents, water solubility index, and cation exchange capacity of steam-exploded wheat bran extrudate were all superior to raw wheat bran extrudate. In summary, this study demonstrates that steam explosion improves the extrusion capacity of wheat bran and facilitates its utilization.
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High concentrations of fermentable sugars are a demand for economical bioethanol production. A single process strategy cannot comprehensively solve the limiting factors in high-solid enzymatic hydrolysis. The multiple intensification strategies in this study achieved the goal of preparing high-concentration fermentable sugars of corn stalk with high solid loading and low enzyme loading. First, steam explosion pretreatment enhanced the hydrophilicity of substrates and enzymatic accessibility. Second, periodic peristalsis was used to improve the mass transfer efficiency and short the liquefaction time. Additionally, fed-batch feeding and enzyme reduced the enzyme loading. Ultimately, the intensification strategies above showed that the highest fermentable sugar content was 313.8 g/L with a solids loading as much as 50% (w/w) and enzyme loading as low as 12.5 FPU/g DM. Thus, these multiple intensification strategies were promising in the high-solid enzymatic hydrolysis of steam-exploded lignocellulose.
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Vapor , Azúcares , Hidrólisis , PeristaltismoRESUMEN
BACKGROUND: Electric energy is not collected and utilized in biobutanol fermentation. The reason is that the yields of electron shuttles and nanowires are not enough to gather and transfer all electrons to the electrode in liquid fermentation. However, the solid matrix of the adsorption carrier may be conducive to the collection and transfer of electrons because of its good adsorption and conductivity. Therefore, this first-attempt study coupled microbial fuel cell (MFC) with adsorption carrier solid-state fermentation (ACSF). In addition, the effect and mechanism of adsorption carrier solid-state fermentation on power generation were explored. RESULTS: The power generation performance and fermentation performance were improved by ACSF. The power density by polyurethane and carbon felt carrier solid-state fermentation (PC) was 12 times that by no carrier fermentation (NC). The biobutanol yield of absorbent cotton and carbon felt carrier solid-state fermentation (ACC) was increased by 36.86%. Moreover, the mechanism was explored via metabolic flux analysis, cyclic voltammetry and scanning electron microscopy. The results of metabolic flux analysis showed that more electrons were produced and more carbon flowed to biobutanol production. The cyclic voltammetry results revealed that more riboflavin was produced to enhance extracellular electron transport (EET) by ACSF. The scanning electron microscopy image showed that the adsorption capacity and aggregation degree of bacteria were increased on the electrode and nanowires were observed by ACSF. CONCLUSIONS: A new fermentation mode was established by coupling MFC with ACSF to improve substrate utilization, which will provide crucial insights into the fermentation industry. In addition, the ACSF is an effective method to enhance power generation performance and fermentation performance.
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Ganoderma lucidum polysaccharides (GLP) exhibited excellent immunomodulatory activity. Unfortunately, the structure and immunomodulatory activity of GLP are still unclear. GLP was separated into two fractions [high Mw Restriction Fragment Length Polymorphism (RGLP) and low Mw EGLP] using 10 kDa cut-off ultrafiltration membrane. Although the RGLP content was low in GLP, the immunomodulatory activity in RGLP was significantly higher than that of EGLP. Moreover, RGLP was further separated via the Sephacryl column to obtain RGLP-1 showed the best immunomodulatory activity in the macrophage RAW264.7 model. Structural analysis revealed that RGLP-1 was 3,978 kDa and mainly consisted of glucose. Periodate oxidation, Smith degradation, and methylation results indicated that RGLP-1 is a ß-pyran polysaccharide mainly with 1â3, 1â4, 1â6, and 1â3, 6 glycosyl bonds at a molar ratio of 40.08: 8.11: 5.62: 17.81. Scanning electron microscopy, atomic force microscopy, and Congo red experiments revealed that RGLP-1 intertwined with each other to form circular aggregates and might possess a globular structure with triple-helix conformation in water. Overall, these results provide RGLP-1 as a potential functional food ingredient or pharmaceutical for immunomodulatory.
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This case report describes a 22-year-old man with a pharyngeal foreign body sensation arising from the left side of the postpharyngeal wall. Histological examination showed a biphasic pattern of epithelioid and spindle cells including glandular differentiation. The tumour was positive for vimentin and SS18-SSX, and the spindle cells were positive for bcl-2; in contrast, the epithelioid tumour cells were positive for pan-cytokeratin, epithelial membrane antigen and CD99. There was no INI-loss in tumour cells. Then, the presence of the SYT-SSX gene fusion was demonstrated by fluorescence in situ hybridization. In addition, androgen receptor gene somatic mutations were detected by next-generation sequencing. However, 6 months postoperatively, the patient had neither developed a recurrence nor received adjuvant radiotherapy and chemotherapy. Accurate diagnosis depends on morphological and immunohistochemical examination and a proper molecular analysis, and novel technologies can detect a wide variety of genetic alterations. Although androgen receptor somatic mutations cannot provide addition treatment at present, surgical resection with a clean margin and follow-up is an appropriate approach.
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BACKGROUND: Myocardial infarction (MI) triggers a strong inflammatory response that is associated with myocardial fibrosis and cardiac remodeling. Interleukin (IL)-1ß and IL-18 are key players in this response and are controlled by NLRP3-inflammatory bodies. Oridonin is a newly reported NLRP3 inhibitor with strong anti-inflammatory activity. We hypothesized that the covalent NLRP3 inhibitor Oridonin could reduce IL-1ß and IL-18 expression and ameliorate myocardial fibrosis after myocardial infarction in mice, improve poor heart remodeling, and preserve heart function. METHODS: Male C57BL/6 mice were subjected to left coronary artery ligation to induce MI and then treated with Oridonin (1, 3, or 6 mg/kg), MCC950 (10 mg/kg), CY-09 (5 mg/kg) or saline three times a week for two weeks. Four weeks after MI, cardiac function and myocardial fibrosis were assessed. In addition, myocardial expressions of inflammatory factors and fibrotic markers were analyzed by western blot, immunofluorescence, enzyme-linked immunosorbent assay, and quantitative real-time polymerase chain reaction. RESULTS: Oridonin treatment preserved left ventricular ejection fraction and fractional shortening, and markedly limited the myocardial infarct size in treated mice. The myocardial fibrosis was lower in the 1 mg/kg group (15.98 ± 1.64)%, 3 mg/kg group (17.39 ± 2.45)%, and 6 mg/kg group (16.76 ± 3.06)% compared to the control group (23.38 ± 1.65)%. Moreover, similar with the results of Oridonin, MCC950 and CY-09 also preserved cardiac function and reduced myocardial fibrosis. The expression levels of NLRP3, IL-1ß and IL-18 were decreased in the Oridonin treatment group compared to non-treated group. In addition, myocardial macrophage and neutrophil influxes were attenuated in the Oridonin treated group. CONCLUSIONS: The covalent NLRP3-inflammasome inhibitor Oridonin reduces myocardial fibrosis and preserves cardiac function in a mouse MI model, which indicates potential therapeutic effect of Oridonin on acute MI patients.
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Antiinflamatorios/farmacología , Diterpenos de Tipo Kaurano/farmacología , Inflamasomas/antagonistas & inhibidores , Infarto del Miocardio/tratamiento farmacológico , Miocitos Cardíacos/efectos de los fármacos , Proteína con Dominio Pirina 3 de la Familia NLR/antagonistas & inhibidores , Función Ventricular Izquierda/efectos de los fármacos , Remodelación Ventricular/efectos de los fármacos , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Fibrosis , Furanos , Compuestos Heterocíclicos de 4 o más Anillos/farmacología , Indenos , Inflamasomas/metabolismo , Interleucina-1beta/metabolismo , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , Ratones Endogámicos C57BL , Infarto del Miocardio/metabolismo , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Infiltración Neutrófila/efectos de los fármacos , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Receptores de Interleucina-18/metabolismo , Transducción de Señal , Volumen Sistólico/efectos de los fármacos , Sulfonamidas , Sulfonas/farmacología , Tiazolidinas/farmacología , Tionas/farmacologíaRESUMEN
A new sequence of steam explosion (SE) with periodic peristalsis (PP) exploited to fractionate corn pericarp (CP), and its high solid cellulosic hydrolysis to increase sugar yield. In this investigation, the optimum SE-condition was 0.8 MPa/5 min., recovered around 12.62 % total sugars than untreated CP, whereas glucan and xylan digestibility reached around 97 % and 87 %, respectively. Besides that, the unground SECP conversion increased by 27.10 % glucan and 34.18 % xylan than the ground one. FE-SEM, FTIR, XRD results confirmed that SE significantly fractionated the amorphous substances that driven the increment of the crystallinity index. SE changed the functional groups without altering the lignin, and also the formation of degradations products was negligible and not detrimental to sugars conversion. An unpolluted SEPP enzymatic hydrolysis system at high solid loading (25 %) with compatible low cellulase dose (15 FPU g-1 solids) was beneficial to intensified sugars conversion.
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Biotecnología/métodos , Vapor , Xilanos/química , Zea mays/química , Celulasa/química , Hidrólisis , Lignina/química , Microscopía Electrónica de Rastreo/métodos , Peristaltismo , Fenómenos Físicos , Espectroscopía Infrarroja por Transformada de Fourier/métodos , Azúcares/química , Difracción de Rayos X/métodosRESUMEN
Solid-state fermentation, featured by water-saving, eco-friendly and high concentration product, is a promising technology in lignocellulosic ethanol industry. However, in solid-state fermentation system, large gas content inside the substrate directly leads to high oxygen partial pressure and inhibits ethanol fermentation. Z. mobilis can produce ethanol from glucose near the theoretical maximum value, but this ethanol yield would be greatly decreased by high oxygen partial pressure during solid-state fermentation. In this study, we applied N2 periodic pulsation process intensification (NPPPI) to ethanol solid-state fermentation, which displaced air with N2 and provided a proper anaerobic environment for Z. mobilis. Based on the water state distribution, the promotion effects of NPPPI on low solid loading and solid-state fermentation were analyzed to confirm the different degrees of oxygen inhibition in ethanol solid-state fermentation. During the simultaneous saccharification solid-state fermentation, the NPPPI group achieved 45.29% ethanol yield improvement and 30.38% concentration improvement compared with the control group. NPPPI also effectively decreased 58.47% of glycerol and 84.24% of acetic acid production and increased the biomass of Z. mobilis. By coupling the peristaltic enzymatic hydrolysis and fed-batch culture, NPPPI made the ethanol yield and concentration reach 80.11% and 55.06 g/L, respectively, in solid-state fermentation.
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Etanol/metabolismo , Fermentación , Nitrógeno/metabolismo , Zymomonas/metabolismo , Biomasa , Hidrólisis , Presión , Zea mays/químicaRESUMEN
Oenothein B (OEB) exhibits extensive biological activities, but few investigations have been carried out on the pharmacologic influence of OEB on longevity in any organism. To explore the potential pharmacological ability of OEB to postpone the progression of age-related degenerative processes and diseases, we monitored the effects of OEB isolated from Eucalyptus leaves on the lifespan of Caenorhabditis elegans (C. elegans) at four different concentrations. We found that OEB increased the median lifespan of worms by up to 22% in a dose-dependent manner. Further studies demonstrated that OEB significantly enhanced youthfulness (healthy lifespan) by increasing the whole adult life's locomotory mobility, reducing age pigment and reactive oxygen species (ROS) accumulation, and enhancing thermal stress resistance. Furthermore, the genes daf-16, age-1, eat-2, sir-2.1, and isp-1 were required for the healthy longevity benefits induced by OEB, but not the genes mev-1 and clk-1. Taken together, OEB might modulate multiple genetic pathways involved in insulin/IGF-1 signaling (IIS) via age-1 and daf-16, the dietary restriction (DR) pathway via eat-2 and sir-2.1, and the mitochondrial electron transport chain via isp-1 to promote healthy lifespan including the reduction of age pigment and ROS accumulation and the enhancement of locomotory mobility, thermal stress tolerance and lifespan. These findings indicated that OEB has the potential to be developed into the next generation of multi-target drugs for prolonging healthy lifespan and intervening in age-related diseases.
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Caenorhabditis elegans/efectos de los fármacos , Eucalyptus/química , Taninos Hidrolizables/farmacología , Longevidad/efectos de los fármacos , Animales , Caenorhabditis elegans/fisiología , Taninos Hidrolizables/química , Taninos Hidrolizables/aislamiento & purificación , Estrés Oxidativo/efectos de los fármacos , Fitoquímicos/química , Fitoquímicos/aislamiento & purificación , Fitoquímicos/farmacologíaRESUMEN
Effective pretreatment process to improve enzymatic saccharification and decrease inhibitors generation is a key operation involved in the lignocellulosic bioconversion. The pretreatment of steam explosion associated with ammonium sulfite (SEAS) process was carried out to investigate the effect on enzymatic hydrolysis and fermentation production as a combinatorial pretreatment. Results showed that after pretreatment (1.0 MPa, 30 min, 20%w/w ammonium sulfite added), the phenolic inhibitors derived from lignin significantly removed (37.8%), which transformed to chemical humic acid (humic acid and fulvic acid) mostly. Sugar conversion (glucan (77.8%) and xylan (73.3%)) and ethanol concentration (40.8 g/L) of combinatorial pretreated samples were increased by 24.7% and 33.8%, respectively, compared with steam explosion (SE) pretreated samples. FT-IR and elemental analysis results indicated that the lignin structure changed and aromatization degree increased after SEAS pretreatment. In addition, the ratio of C/N decreased and compost maturity degree increased with the holding time. The effect on the growth of wheat seedlings of soluble fulvic acid solution from combinatorial pretreatment was investigated, where below 1% (w/w) concentration did contribute to growth. Therefore, one-step chemical pretreatment process could be provided for inhibitors removal, enzymatic saccharification increase, and chemical humic acid formation as well.
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Celulasa/química , Compuestos de Amonio Cuaternario/química , Vapor , Sulfitos/química , Zea mays/química , Glucanos/química , Hidrólisis , Xilanos/químicaRESUMEN
An efficient hybrid pretreatment method was developed for butanol production from corn stover using dilute sulfuric acid (DA) and aqueous ammonia (AA). With the optimized AA concentration, treatment temperature and time of 10% AA, 80⯰C and 24â¯h, the hybrid pretreatment could effectively dissolve hemicellulose and lignin with solid recovery rate of 37.45% and lignin reduction rate of 86.77% compared to those of 57.75% and 45.84% from single DA pretreatment. By washing 1 time after each step treatment, sugar yield and butanol production were increased to 401.76â¯mg/g-CS and 10.89â¯g/L from 346.04â¯mg/g-CS and 9.33â¯g/L obtained without washing. Compared with conventional single DA and AA pretreatment methods, wastewater generation was reduced to 0.83â¯L/g-butanol from 2.11 and 3.46â¯L/g-butanol, indicating this hybrid pretreatment could be an effective approach for improving butanol production from lignocellulosic feedstocks.
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Amoníaco/química , Butanoles/química , Ácidos Sulfúricos/química , Aguas Residuales/química , Zea mays/química , Hidrólisis , Técnicas de Dilución del Indicador , Lignina/química , Polisacáridos/químicaRESUMEN
Gas double-dynamic solid-state fermentation (SSF) is a promising strategy with the potential in transforming open-pattern fermentation into closed-pattern fermentation. This paper investigated gas double-dynamic SSF performance in cultivating Coniothyrium minitans (C. minitans), as well as its effect on physiology of C. minitans. Results showed that gas double-dynamic increased biomass content by 48.6%. High temperature impeded pycnidia formation and increased glycine production. More pycnidia formed in solid matrix at 20⯰C, which was responsible for higher conidia production (1.5 (±0.03)â¯×â¯1010â¯spores/g dry mass), indicating decisive role of high temperature in pycnidia formation of C. minitans in solid-state fermentation. Higher glycine content may be the response of high temperature stress which has close relationship with pycnidia and conidia production. Based on the findings, a two-step strategy for gas double-dynamic SSF was proposed and an satisfactory conidia production was obtained while fermentation period shortened.
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Ascomicetos , Fermentación , Esporas Fúngicas , Biomasa , CalorRESUMEN
A series of γ-[Glu](n=2,3,4)-Val or γ-[Glu](n=2,3,4)-Met were synthesized in the presence of donor (Gln) and corresponding acceptor (Val or Met) through transpeptidation catalyzed by the glutaminase from Bacillus amyloliquefaciens. Gln in excess significantly (pâ¯<â¯.05) improved the yield of γ-[Glu](n>1)-Val/Met except for γ-Glu-Val/Met. The Km values for transpeptidase activity to yield γ-[Glu](n=0,1,2,3)-Val increased with an elevated n, but remained essentially the same irrespective of n value for γ-[Glu](n=0,1,2)-Met (which were 31-44% of that for γ-[Glu]3-Met). The highest Km value appearing when nâ¯=â¯3 (γ-[Glu]3-Val or γ-[Glu]3-Met) suggested the rising difficulty for synthesis when the number of donor increases. All the γ-[Glu]n-Val/Met substances exhibited kokumi properties and enhanced the continuity and umami taste of soy sauce as well as the thickness, mouthfulness and umaminess of model chicken broth. These results indicate the potential of the γ-[Glu]n-Val and γ-[Glu]n-Met as food flavor enhancers.
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Bacillus amyloliquefaciens/enzimología , Dipéptidos/metabolismo , Glutaminasa/metabolismo , Péptidos/metabolismo , Catálisis , Metionina/metabolismo , Alimentos de Soja , Gusto , Valina/metabolismoRESUMEN
Solid state enzymatic hydrolysis (SSEH) has many advantages, such as higher sugar concentration, lower operating costs, and less energy input. It should be a potential approach for the industrial application of lignocellulosic ethanol. The purpose of this work is to review the enzymatic hydrolysis of lignocellulosic biomass from low to high solids loading and introduce its both challenges and perspectives. The limitations of SSEH, including inhibition effects, water constraint, and rheology characteristic, are summarized firstly. Various strategies for overcoming these limitations are proposed correspondingly. Fed batch process and its feeding strategy to improve the SSEH efficiency are then discussed. Finally, several intensification methods, hydrolysis reactor, and pilot- and demonstration-scale operations of SSEH are described. In-depth analysis of main limitations and development of novel intensification methods and reactors should provide an effective way to achieve large-scale implementation of SSEH.
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The simultaneous saccharification and fermentation (SSF) of corn stover biomass for ethanol production was performed by integrating steam explosion (SE) pretreatment, hydrolysis and fermentation. Higher SE pretreatment severity and two-step size reduction increased the specific surface area, swollen volume and water holding capacity of steam exploded corn stover (SECS) and hence facilitated the efficiency of hydrolysis and fermentation. The ethanol production and yield in SSF increased with the decrease of particle size and post-washing of SECS prior to fermentation to remove the inhibitors. Under the SE conditions of 1.5MPa and 9min using 2.0cm particle size, glucan recovery and conversion to glucose by enzymes were 86.2% and 87.2%, respectively. The ethanol concentration and yield were 45.0g/L and 85.6%, respectively. With this two-step size reduction and post-washing strategy, the water utilization efficiency, sugar recovery and conversion, and ethanol concentration and yield by the SSF process were improved.
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Etanol/química , Vapor , Zea mays/química , Biomasa , Explosiones , Fermentación , Glucosa/química , HidrólisisRESUMEN
Levulinic acid production, directly from lignocellulosic biomass, resulted in low yields due to the poor substrate accessibility and occurrence of side reactions. The effects of reaction conditions, enzymatic pretreatment, and inhibitor addition on the conversion of steam-exploded rice straw (SERS) short fiber to levulinic acid catalyzed by solid superacid were investigated systematically. The results indicated that the optimal reaction conditions were temperature, time, and solid superacid concentration combinations of 200 °C, 15 min, and 7.5 %. Enzymatic pretreatment improved the substrate accessibility to solid superacid catalyst, and p-hydroxyanisole inhibitor reduced the side reactions during reaction processes, which helped to increase levulinic acid yield. The levulinic acid yield reached 25.2 % under the optimal conditions, which was 61.5 % higher than that without enzymatic pretreatment and inhibitor addition. Therefore, enzymatic pretreatment coupled with the addition of p-hydroxyanisole increased levulinic acid production effectively, which contributed to the value-added utilization of lignocellulosic biomass.
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Anisoles/farmacología , Celulasa/metabolismo , Ácidos Levulínicos/metabolismo , Oryza/química , Vapor , Residuos , Biocatálisis/efectos de los fármacos , Biomasa , Lignina/metabolismo , Oryza/efectos de los fármacos , Temperatura , Factores de TiempoRESUMEN
The acetone-butanol-ethanol (ABE) fermentation of lignocellulose at high solids content has recently attracted extensive attention. However, the productivity of high solids ABE fermentation of lignocellulose is typically low in traditional processes due to the lack of efficient intensifying methods. In the present study, periodic peristalsis, a novel intensifying method, was applied to improve ABE production by the simultaneous saccharification and fermentation (SSF) of steam-exploded corn straw using Clostridium acetobutylicum ATCC824. The ABE concentration and the ABE productivity of SSF at a solids content of 17.5% (w/w) with periodic peristalsis were 17.1 g/L and 0.20 g/(L h), respectively, which were higher than those obtained under static conditions (15.2 g/L and 0.14 g/(L h)). The initial sugar conversion rate over the first 12 h with periodic peristalsis was 4.67 g/(L h) at 10 FPU/g cellulase dosage and 15% (w/w) solids content, an increase of 49.7% compared with the static conditions. With periodic peristalsis, the period of batch fermentation was shortened from 108 h to 84 h. The optimal operating regime was a low frequency (6 h-1) of periodic peristalsis in the acid-production phase (0-48 h) of SSF. Therefore, periodic peristalsis should be an effective intensifying method to increase the productivity of ABE fermentation at high solids content.