Fractionation of eucalyptus globulus wood by glycerol-water pretreatment: optimization and modeling

A glycerol-organosolv process can be a good alternative for Eucalyptus wood fractionation into its main compounds, improving the enzymatic saccharification of the cellulose. A study of process variables - glycerol−water percent content, temperature, and process time - was carried out using a Box-Behnken experimental design. The cellulose obtained from pretreated solids was recovered almost quantitatively, leading to a solid with a high percentage of cellulose (77 g/100 g of pretreated solid), low lignin content (9 g/100 g of pretreated solid), and 18% of residual hemicellulose in the solid at 200 °C, 56% of glycerol−water and 69 min. The enzymatic saccharification was enhanced achieving 98% cellulose-to-glucose conversion (under conditions: liquid to solid ratio 20 g/g and enzyme loading 20 FPU/g of solid). This study contributes to the improvement of biomass fractionation by exploring an eco-friendly treatment which allows for almost complete wood fractionation into constituents and high levels of glucose recovery available for subsequent yeast fermentation to bioethanol.The authors A. Romani and F. B. Pereira thank to the Portuguese Foundation for Science and Technology (FCT, Portugal) for their fellowships (grant number: SFRH/BPD/77995/2011 and SFRH/BD/64776/2009, respectively)

Comparative study of organosolv lignin extracted from prairie cordgrass, switchgrass and corn stover

► Organosolv lignin extracted from three feedstocks was analyzed. ► Lignin origin influences its properties. ► Examined lignins were found low in contaminants. ► Examined lignins were found highly phenolic and applicable in vanillin production. Lignin extracted from prairie cordgrass, switchgrass, and corn stover (using ethyl acetate–ethanol–water organosolv pretreatment) was analyzed and characterized using several methods. These methods included analysis of purity (by determination of Klason lignin, carbohydrate, and ash contents), solubility (with several organic solvents), phenolic group analysis (ultraviolet ionization difference spectra, and nitrobenzene oxidation), and general functional group analysis (by 1H NMR). Results showed that all the examined lignin samples were relatively pure (contained over 50% Klason lignin, less than 5% carbohydrate contamination, and less than 3% ash), but switchgrass-derived lignin was observed to be the purest. All the lignins were found to contain high amounts of phenolic groups, while switchgrass-derived lignin was the most phenolic, according to the ionization difference spectra. Nitrobenzene oxidation revealed that all the lignin samples contained available guaiacyl units in high amounts

Catalyzed modified clean fractionation of switchgrass

Switchgrass was used as a lignocellulosic feedstock for second generation ethanol production, after pretreatment using sulfuric acid-catalyzed modified clean fractionation based on NREL's (National Renewable Energy Laboratory) original procedure. Optimization of temperature, catalyst concentration and solvent composition was performed using Response Surface Methodology, and 59.03 ± 7.01% lignin recovery, 84.85 ± 1.34% glucose, and 44.11 ± 3.44% aqueous fraction xylose yields were obtained at 140.00 °C, 0.46% w/w catalyst concentration, 36.71% w/w ethyl acetate concentration, and 25.00% w/w ethanol concentration. The cellulose fraction did not inhibit the fermentation performance of Saccharomyces cerevisiae and resulted in an ethanol yield of 89.60 ± 2.1%

MicroRNA‐146a and RBM4 form a negative feed‐forward loop that disrupts cytokine mRNA translation following TLR4 responses in human THP‐1 monocytes

Within hours after its initiation, the severe systemic inflammatory response of sepsis shifts to an adaptive anti-inflammatory state with coincident immunosuppression. This anti-inflammatory phenotype is characterized by diminished proinflammatory cytokine gene expression in response to toll-like receptor (TLR) stimulation with bacterial endotoxin/ LPS, also known as endotoxin tolerance/adaptation. Our and other studies have established that gene-specific reprogramming following TLR4 responses independently represses transcription and translation of proinflammatory genes such as TNFα. We also previously demonstrated that TNFα and IL-6 mRNA translation is repressed in endotoxin adapted THP-1 human monocytes by a miRNA-based mechanism involving the argonaute family protein Ago2. Here, we further define the molecular nature of reprogramming translation by showing that TLR4-induced microRNA-146 promotes a feed-forward loop that modifies the subcellular localization of the RNA-binding protein RBM4 and promotes its interaction with Ago2. This interaction results in assembly of a translation repressor complex that disrupts TNFα and IL-6 cytokine synthesis in endotoxin adapted THP-1 monocytes. This novel molecular path prevents phosphorylation of RBM4 on serine-309 by p38 MAPK, which leads to RBM4 accumulation in the cytosol and interaction with Ago2. We further find that microRNA-146a knockdown by antagomirs or inhibiting protein phosphatases by okadaic acid, increases p38 MAPK phosphorylation and results in RBM4 serine-309 phosphorylation and nuclear re-localization, which disrupts RBM4 and Ago2 interactions and restores TLR4-dependent synthesis of TNFα and IL-6. We conclude that miR-146a plays a diverse and critical role in limiting an excessive acute inflammatory reaction

Associations between joint effusion in the knee and gene expression levels in the circulation: a meta-analysis

Objective: To identify molecular biomarkers for early knee osteoarthritis (OA), we examined whether joint effusion in the knee associated with different gene expression levels in the circulation. Materials and Methods: Joint effusion grades measured with magnetic resonance (MR) imaging and gene expression levels in blood were determined in women of the Rotterdam Study (N=135) and GARP (N=98). Associations were examined using linear regression analyses, adjusted for age, fasting status, RNA quality, technical batch effects, blood cell counts, and BMI. To investigate enriched pathways and protein-protein interactions, we used the DAVID and STRING webtools. Results: In a meta-analysis, we identified 257 probes mapping to 189 unique genes in blood that were nominally significantly associated with joint effusion grades in the knee. Several compelling genes were identified such as C1orf38 and NFATC1. Significantly enriched biological pathways were: response to stress, gene expression, negative regulation of intracellular signal transduction, and antigen processing and presentation of exogenous pathways. Conclusion: Meta-analyses and subsequent enriched biological pathways resulted in interesting candidate genes associated with joint effusion that require further characterization. Associations were not transcriptome-wide significant most likely due to limited power. Additional studies are required to replicate our findings in more samples, which will greatly help in understanding the pathophysiology of OA and its relation to inflammation, and may result in biomarkers urgently needed to diagnose OA at an early stage