The integrated production of hydrochar and methane from lignocellulosic fermentative residue coupling hydrothermal carbonization with anaerobic digestion.

The popularization of large-scale biogas project makes the disposal of fermentative residue an urgent issue to be solved. Hydrothermal carbonization (HTC) technology is suitable for treating wet biomass to produce carbonaceous materials. In this study, the solid residue from the two-phase anaerobic digestion (AD) was hydrothermally converted in the range of 180-240 °C, and the hydrochar and aqueous components were characterized for subsequent utilization. The heating values of hydrochar were indicated to be increased by 14.2% and 16.6% at 210 °C and 240 °C as compared with feedstock, and also the specific surface areas were 34.8 m2/g and 27.1 m2/g with 17.4- and 13.3-fold enhancement, respectively. The migration of elements such as S, Cl, K to aqueous phase was beneficial for fuel application. The mesoporous pores were dominant in hydrochars with ample oxygenated functional groups. In addition, the wastewater involved organic acids, phenols, and nitrogen-containing compounds, etc. Evaluating the biodegradability by AD, it was found that when the initial concentration was ≤8 g COD/L, the maximum methane yields up to 275.9 mL CH4/g CODremoval and 277.6 mL CH4/g CODremoval were obtained. The enhanced toxicity/inhibition of representative pollutants on microorganisms was significant at higher organic loading, which could be indicated in the microbial structure and diversity. As a conclusion, the integrated production of hydrochar and methane will provide an extended route for further processing of lignocellulosic fermentative residue.

Energy recovery from high ash-containing sewage sludge: Focusing on performance evaluation of bio-fuel production.

Hydrothermal liquefaction (HTL) has shown great potential to convert sewage sludge (SS) with high moisture into bio-crude. However, the disposal and reutilization of hydrothermal liquefaction wastewater (HTLWW) is a critical issue. Anaerobic digestion (AD) is proven to be an alternative to treat organic wastewater. Therefore, energy recovery from high ash-containing SS was studied by integrating AD with HTL. The effect of temperature on HTL efficiency was investigated and then methane production from HTLWW was conducted by AD with organic loading increasing from 2 g COD/L to 6 g COD/L. Results showed that the maximum bio-crude yield of 23.5 % was obtained at 350 °C. Methane yield of 309.4 mL CH4/g CODremoved was achieved at 2 g COD/L with COD removal rate of 72.5 %. Meanwhile, the microbial structure and abundance showed great shifts resulting from the adaptation to complex compounds. JGI-000079-D21, Aminicenantales, and Bacteroidetes_ vadinHA17 predominated in the bacterial community. Due to the presence of the toxic substances in HTLWW, such as phenolic and nitrogenous heterocyclic compounds, there was a decrease in methane yield when the organic loading was higher than 4 g COD/L. The organic matters in extracellular polymeric substances (EPS) were rich in fulvic acid-like and humic acid-like substances due to the attack and stimulation of toxicants. Under the condition of unstable fermentation, Advenella and Bacillus first appeared as phenol and pyridine degrading bacteria, respectively. The microbial diversity declined sharply to demonstrate the toxic effect of the refractory organics existing at high organic loading. The enrichment of Methanosaeta in methanogens meant that acetotrophic metabolism is the dominant pathway in methanogenesis. In this study, the profile of bio-fuel production from high ash-containing SS would provide an integrated reference to treat wet biomass and recover energy simultaneously.

Acidogenic and methanogenic properties of corn straw silage: Regulation and microbial analysis of two-phase anaerobic digestion.

Corn straw silage (CSS) is one of the organic solid residues available for biogas production. The aim of this study was to investigate the possibility and optimal controlling strategy for anaerobic digestion (AD) of CSS. Four leaching bed reactors (LBR) were operated at different pH. Maximum volatile fatty acids (VFAs) concentration of 19.34 g/L was reached at pH 8.0 with acetic and propionic acids as dominant VFAs. The subsequent microbial analysis indicated that abundant bacteria were Firmicutes, Bacteroidetes and Proteobacteria. UASB as methanogenic reactor was integrated with the LBR. The organic loading rate (OLR) could reach 8 g COD/L·d with effective conversion of VFAs. Acetotrophic Methanosaeta and hydrogenotrophic Methanobacterium played major roles in methanogenic process. In the whole process, the results showed that methane yield of 143.4 mL CH4/g volatile solid (VS) was obtained. pH and OLR controls in two-phase AD were feasible for methane production from CSS.

Two-phase anaerobic digestion of lignocellulosic hydrolysate: Focusing on the acidification with different inoculum to substrate ratios and inoculum sources.

Biogas production from lignocellulosic hydrolysate is of great potential for lignocellulosic materials. Two-phase anaerobic digestion was proposed in this study. Acidogenic fermentation was carried out with corn straw hydrolysate as feedstock for volatile fatty acids (VFAs) production. Using anaerobic sludge (AnS), different inoculum to substrate ratios (ISRs) of 0.5:1, 1:1 and 2:1 were investigated. The highest VFAs yield was obtained at ISR of 0.5:1.VFAs composition analysis showed that butyric acid was the predominant acid, followed by acetic acid and propionic acid. The effects of AnS and aerobic sludge (AeS) on the acidogenic performance of hydrolysate were compared. The optimum VFA yields were 0.38 g/g COD-added for AnS and 0.32 g/g COD-added for AeS with HRT of 5 d, respectively. The bacterial diversities of inocula and digestates were analyzed by high-throughput sequencing. Two origins of inocula had distinct bacterial structures, but they did share core communities that included Firmicutes, Chloroflexi, Proteobacteria and Bacteroidetes at phylum level. The bacterial communities of both digestates changed significantly as compared with those in inoculum. Firmicutes was absolutely dominant in all the bacterial species. Therefore, the AeS could be an option as the acidogenic inoculum. The microbial information will be beneficial for the enrichment and acclimatization of microbes. In methanogenic process, VFAs obtained in acidogenic stage could be efficiently converted into methane. The ultimate methane yield at organic loading rate (OLR) of 8 g/L·d could reach 290 mL CH4/g COD-added and 279 mL CH4/g COD-added for AnS and AeS acidified digestate. Two-phase anaerobic digestion was proved to be suitable for bioconversion of lignocellulosic hydrolysate into biogas.

Acidogenic properties of carbohydrate-rich wasted potato and microbial community analysis: Effect of pH.

Vegetable waste is one of the major organic solid residues available for sustainable biogas production. The aim of this study was to investigate the possibility and optimal controlling strategy for acidogenic fermentation of wasted potato (WP). Three leaching bed reactors (LBRs) were operated at various pH values (6.0, 7.0 and 8.0) with an organic loading rate (OLR) of 6.7 g volatile solid/(L·d) and hydraulic retention time of 6 d. Butyric acid-type fermentation with butyric acid as predominant volatile fatty acid (VFA) was observed with a concentration and proportion (of total VFAs) of butyric acid, which were 7.8 g/L, 49.7 % and 9.6 g/L and 52.2 % at pH 6.0 and 7.0, respectively. Conversely, at pH 8.0, mixed acid-type fermentation was observed with acetic and butyric acid as the major VFAs. Control experiment without pH manipulation didn't perform well in VFAs production at first 6 days and then VFAs concentration increased as pH value was adjusted to 8. It was indicated that the inhibition was caused by high undissociated VFAs concentration due to low pH and the VFAs production could be improved through pH control strategy to regulate the undissociated VFAs concentration. According to the bacterial analysis, the microbial community was diverse and Firmicutes were the most important bacteria at different pH conditions. Therefore, the results suggested that a process of pH control might be feasible for stable and efficient acidogenic fermentation.

Circulating miR-126 and miR-130a levels correlate with lower disease risk, disease severity, and reduced inflammatory cytokine levels in acute ischemic stroke patients.

To investigate the correlations of five angiogenesis-related miRNA (miR-126, miR-130a, miR-222, miR-218, and miR-185) expression levels with risk, severity, and inflammatory cytokines levels in acute ischemic stroke (AIS) patients. A total of 148 AIS patients and 148 age- and gender-matched controls were consecutively enrolled. Blood samples were collected from AIS patients and controls, and plasma was separated for miRNAs and cytokine level detection. Plasma levels of miRNAs were evaluated by real-time qPCR method, and inflammatory cytokine levels were detected using an enzyme-linked immunosorbent assay (ELISA). Plasma miR-126 and miR-130a expression levels in AIS patients were lower than those of controls, while the levels of miR-222, miR-218, and miR-185 were elevated in AIS patients compared with controls. After pooling the five miRNA expression levels together, the area under the curve (AUC) for predicting AIS risk was 0.840 (95% CI 0.795-0.885) with a sensitivity of 83.8% and a specificity of 69.6% at the best cut-off point. Plasma miR-126 (r = - 0.402, P < 0.001) and miR-130a (r = - 0.161, P = 0.050) levels were negatively correlated with NIHSS scores, while plasma miR-218 level was positively correlated with NIHSS scores (r = 0.471, P < 0.001). Most importantly, plasma miR-126 expression was negatively correlated with TNF-α (r = - 0.168, P = 0.041), IL-1ß (r = - 0.246, P = 0.003), and IL-6 (r = - 0.147, P = 0.035) levels, while miR-130a expression was negatively correlated with TNF-α (r = - 0.287, P < 0.001), IL-1ß (r = - 0.168, P = 0.041), and IL-6 (r = - 0.239, P = 0.003) expression levels and positively associated with IL-10 level (r = 0.261, P = 0.001). Circulating miR-126 and miR-130a levels correlate with lower disease risk, decreased disease severity, and reduced inflammatory cytokine levels in AIS patients.

Microbial and nutritional regulation of high-solids anaerobic mono-digestion of fruit and vegetable wastes.

The anaerobic digestion of single fruit and vegetable wastes (FVW) can be easily interrupted by rapid acidogenesis and inhibition of methanogen, and the digestion system tends to be particularly unstable at high solid content. In this study, the anaerobic digestion of FVW in batch experiments under mesophilic condition at a high solid concentration of 10% was successfully conducted to overcome the acidogenesis problem through several modifications. Firstly, compared with the conventional anaerobic sludge (CAS), the acclimated anaerobic granular sludge (AGS) was found to be a better inoculum due to its higher Archaea abundance. Secondly, waste activated sludge (WAS) was chosen to co-digest with FVW, because WAS had abundant proteins that could generate intermediate ammonium. The ammonium could neutralize the accumulated volatile fatty acids (VFAs) and prevent the pH value of the digestion system from rapidly decreasing. Co-digestion of FVW and WAS with TS ratio of 60:40 gave the highest biogas yield of 562 mL/g-VS and the highest methane yield of 362 mL/g-VS. Key parameters in the digestion process, including VFAs concentration, pH, enzyme activity, and microbial activity, were also examined.

Circulating pro-angiogenic and anti-angiogenic microRNA expressions in patients with acute ischemic stroke and their association with disease severity.

The main objectives of this study are to evaluate 28 selected pro-angiogenic and anti-angiogenic microRNA (miRNA) expressions in plasma of acute ischemic stroke (AIS) patients and controls and to assess the correlations of these miRNAs with risk and severity of AIS. In the exploring stage, 10 AIS patients and 10 controls with vascular risk factors were enrolled. And in the validating stage, 106 AIS patients and 110 controls with the same eligibility were recruited. Blood samples were collected from participants within 24 h post the onset of symptoms, and plasma levels of miRNAs were evaluated by the qPCR method. In the exploring stage, 11 differentially expressed miRNAs (DEM) were identified and included into the validating stage. In the validating stage, the expression of miR-126, miR-130a, and miR-378 in plasma declined in the AIS patients; however, miR-222, miR-218, and miR-185 plasma levels were elevated. Univariate and multivariate logistic regression analysis disclosed that miR-126, miR-130a, miR-222, miR-218, and miR-185 were independent predicting factors for AIS. When these five DEMs were combined together, they presented a good diagnostic value with an area under curve (AUC) value of 0.767 (95% CI 0.705-0.829), sensitivity of 87.7%, and specificity of 54.5% at best cutoff point. Additionally, miR-126, miR-378, miR-101, miR-222, miR-218, and miR-206 were associated with National Institutes of Health Stroke Scale (NIHSS) score. Circulating miR-126, miR-130a, miR-222, miR-218, and miR-185 could be served as promising and independent biomarkers for risk of AIS, and miR-126, miR-378, miR-222, miR-101, miR-218, and miR-206 could be used for disease severity management of AIS.

Conversion of vegetable wastes to organic acids in leaching bed reactor: Performance and bacterial community analysis.

Vegetable wastes (VWs), which contained abundant solid content, were digested in a leaching bed reactor (LBR). The tested VWs for acidification in the LBR included cabbage, potato, and tomato vine. The digestion in the LBR was carried out at the same organic loading rate of 25 g volatile solid (VS) per liter. It was found that cabbage and potato produced much more volatile fatty acids (VFAs) than tomato vine, probably because readily degradable components were more abundant in cabbage and potato. The retention time to digest each feedstock was different. It took 4, 5, and 8 days for cabbage, potato, and tomato vine to completely disappear in the reactor, respectively. The profiles of the VFAs generated from the three VWs were examined. In all cases, the predominant VFAs were acetic acid and butyric acid, although the relative abundance of individual VFA varied across the tested leachate samples. The bacterial community compositions of the leachates were analyzed by high throughput sequencing, and it was found that the feedstock strongly affected the bacterial community structure in the acidogenic process. All leachates had distinct bacterial community structure, although they did share a common set of core communities that included Proteobacteria, Firmicutes, and Bacteroidetes.

Simultaneous glucose and xylose uptake by an acetone/butanol/ethanol producing laboratory Clostridium beijerinckii strain SE-2.

OBJECTIVES: Most butanol-producing strains of Clostridium prefer glucose over xylose, leading to a slower butanol production from lignocellulose hydrolysates. It is therefore beneficial to find and use a strain that can simultaneously use both glucose and xylose. RESULTS: Clostridium beijerinckii SE-2 strain assimilated glucose and xylose simultaneously and produced ABE (acetone/butanol/ethanol). The classic diauxic growth behavior was not seen. Similar rates of sugar consumption (4.44 mM glucose h(-1) and 6.66 mM xylose h(-1)) were observed suggesting this strain could use either glucose or xylose as the substrate and it has a similar capability to degrade these two sugars. With different initial glucose:xylose ratios, glucose and xylose were consumed simultaneously at rates roughly proportional to their individual concentrations in the medium, leading to complete utilization of both sugars at the same time. CONCLUSIONS: ABE production profiles were similar on different substrates. Transcriptional studies on the effect of glucose and xylose supplementation, however, suggests a clear glucose inhibition on xylose metabolism-related genes is still present.

Biodiesel production from rubber seed oil using poly (sodium acrylate) supporting NaOH as a water-resistant catalyst.

Poly (sodium acrylate) supporting NaOH (NaOH/NaPAA) was prepared by in situ polymerization of aqueous solution of acrylic acid with an over-neutralization by adding excess of NaOH. NaOH/NaPAA presented a promising selectivity for water absorbency and good water retention with negligible swelling capacity in the organic solvents of methanol, glycerol, rubber seed oil methyl esters, and rubber seed oil. NaOH/NaPAA catalysts showed a basic strength of 15.0

New general sulfinylating process for asymmetric synthesis of enantiopure sulfinates and sulfoxides.

[reaction: see text] A general process for the efficient synthesis of sulfinyl transfer agents has been developed using cinchona alkaloids quinine and quinidine as chiral auxiliaries. The importance of these new and unique sulfinyl transfer agents is exemplified by the expedient synthesis of several sulfoxides in excellent enantiopurities and high yields.