Surfactants facilitated glycerol organosolv pretreatment of lignocellulosic biomass by structural modification for co-production of fermentable sugars and highly reactive lignin.

This study reported that surfactants could facilitate the organosolv pretreatment of lignocellulosic biomass (LCB) to produce fermentable sugars and highly active lignin. Under the optimized conditions, the surfactant-assisted glycerol organosolv (saGO) pretreatment achieved 80.7% delignification with a retention of 93.

Advances in organosolv modified components occurring during the organosolv pretreatment of lignocellulosic biomass.

The valorization of organosolv pretreatment (OP) is a required approach to the industrialization of the current enzyme-mediated lignocellulosic biorefinery. Recent literature has demonstrated that the solvolysis happening in the OP can modify the soluble components into value-added active compounds, namely organosolv modified lignin (OML) and organosolv modified sugars (OMSs), in addition to protecting them against excessive degradation. Among them, the OML is coincidental with the "lignin-first" strategy that should render a highly reactive lignin enriched with β-O-4 linkages and less condensed structure by organosolv grafting, which is desirable for the transformation into phenolic compounds.

Advances and perspectives on mass transfer and enzymatic hydrolysis in the enzyme-mediated lignocellulosic biorefinery: A review.

Enzymatic hydrolysis is a critical process for the cellulase-mediated lignocellulosic biorefinery to produce sugar syrups that can be converted into a whole range of biofuels and biochemicals. Such a process operating at high-solid loadings (i.e.

Metabolic Engineering for the Comprehensive Utilization of ,-Dimethylformamide-Containing Wastewater.

, -dimethylformamide is frequently present in industrial wastewater and is environmentally detrimental. The current study aims to assess the utilization and biodegradation of , -dimethylformamide-containing wastewater to lessen the associated environmental load. Results show that addition of wastewater containing , -dimethylformamide to fermentation media enhances cellulase production and facilitates cellulose hydrolysis.

Positive role of non-catalytic proteins on mitigating inhibitory effects of lignin and enhancing cellulase activity in enzymatic hydrolysis: Application, mechanism, and prospective.

Fermentable sugar production from lignocellulosic biomass has received considerable attention and has been dramatic progress recently. However, due to low enzymatic hydrolysis (EH) yields and rates, a high dosage of the costly enzyme is required, which is a bottleneck for commercial applications. Over the last decades, various strategies have been developed to reduce cellulase enzyme costs.

Effect of residual extractable lignin on acetone-butanol-ethanol production in SHF and SSF processes.

Background: Lignin plays an important role in biochemical conversion of biomass to biofuels. A significant amount of lignin is precipitated on the surface of pretreated substrates after organosolv pretreatment. The effect of this residual lignin on enzymatic hydrolysis has been well understood, however, their effect on subsequent ABE fermentation is still unknown.

Effect of fermentation stillage of food waste on bioelectricity production and microbial community structure in microbial fuel cells.

A single-chamber microbial fuel cell (MFC) was used in this study to treat recycled stillage obtained from food waste ethanol fermentation. Corresponding substrates inside the system were evaluated by fluorescence spectra, and microbial communities were also investigated. Results demonstrated that output voltage and current, respectively, reached 0.

Concise review on ethanol production from food waste: development and sustainability.

The development of sustainable bioethanol fuel production from food waste has increasingly become an attractive topic. Food waste is recognized as the most available and costless feedstock. Therefore, ethanol production has been adopted as cost-efficient and an ecological way for FW disposal.

Effect of overliming and activated carbon detoxification on inhibitors removal and butanol fermentation of poplar prehydrolysates.

Background: Biomass prehydrolysates from dilute acid pretreatment contain a considerable amount of fermentable sugars for biofuels production. However, carbonyl degradation compounds present severe toxicity to fermentation microbes. Furans (such as furfural and hydroxymethylfurfural), aliphatic acids (such as acetic acid, formic acid and levulinic acid) and phenolic compounds (such as vanillin and syringaldehyde) have been suggested to be the main inhibitors in biomass prehydrolysates.

Detoxification of Organosolv-Pretreated Pine Prehydrolysates with Anion Resin and Cysteine for Butanol Fermentation.

Bioconversion of lignocellulose to biofuels suffers from the degradation compounds formed during pretreatment and acid hydrolysis. In order to achieve an efficient biomass to biofuel conversion, detoxification is often required before enzymatic hydrolysis and microbial fermentation. Prehydrolysates from ethanol organosolv-pretreated pine wood were used as substrates in butanol fermentation in this study.

Synergistic effects of pH and organosolv lignin addition on the enzymatic hydrolysis of organosolv-pretreated loblolly pine.

The effect of ethanol organosolv lignin (EOL) on enzymatic hydrolysis was examined at pH 4.8-6.0.

Stimulation and inhibition of enzymatic hydrolysis by organosolv lignins as determined by zeta potential and hydrophobicity.

Background: Lignin typically inhibits enzymatic hydrolysis of cellulosic biomass, but certain organosolv lignins or lignosulfonates enhance enzymatic hydrolysis. The hydrophobic and electrostatic interactions between lignin and cellulases play critical roles in the enzymatic hydrolysis process. However, how to incorporate these two interactions into the consideration of lignin effects has not been investigated.

Heterologous expression of codon optimized Trichoderma reesei Cel6A in Pichia pastoris.

The Cel6A deficiency has become one of the limiting factors for cellulose saccharification in biochemical conversion of cellulosic biomass to fuels and chemicals. The work attempted to use codon optimization to enhance Trichoderma reesei Cel6A expression in Pichia pastoris. Two recombinants P.

Acetone-butanol-ethanol production from Kraft paper mill sludge by simultaneous saccharification and fermentation.

Paper mill sludge (PS), a solid waste from pulp and paper industry, was investigated as a feedstock for acetone-butanol-ethanol (ABE) production by simultaneous saccharification and fermentation (SSF). ABE fermentation of paper sludge by Clostridium acetobutylicum required partial removal of ash in PS to enhance its enzymatic digestibility. Enzymatic hydrolysis was found to be a rate-limiting step in the SSF.

Detoxification of biomass hydrolysates with nucleophilic amino acids enhances alcoholic fermentation.

Carbonyl compounds generated in biomass pretreatment hinder the biochemical conversion of biomass hydrolysates to biofuels. A novel approach of detoxifying hydrolysates with amino acids for ethanol production was developed. Among the 20 amino acids assessed for their detoxification efficiency and nucleophilicity, cysteine was the most effective one.

Effect of carbonyl inhibitors and their H₂O₂ detoxification on lactic acid fermentation.

Biomass degradation compounds significantly inhibit biochemical conversion of biomass prehydrolysates to biofuels and chemicals, such as lactic acid. To characterize the structure-activity relationship of carbonyl inhibition on lactic acid fermentation, we examined effects of eight carbonyl compounds (furfural, 5-hydroxymethyl furfural, vanillin, syringaldehyde, 4-hydroxybenzaldehyde, phthalaldehyde, benzoic acid, and pyrogallol aldehyde) and creosol on lactic acid production by Lactobacillus delbrueckii. Pyrogallol aldehyde reduced the cell growth rate by 35 % at 1.

Contrasting effects of hardwood and softwood organosolv lignins on enzymatic hydrolysis of lignocellulose.

Identifying an appropriate parameter to elucidate effects of lignin on enzymatic hydrolysis is essential to understand the interactions between enzymes and lignin. Contrasting effects of hardwood organosolv lignin (EOL-SG) and softwood organosolv lignin (EOL-LP) on enzymatic hydrolysis were observed. The addition of EOL-SG (8 g/L) significantly improved the 72 h hydrolysis yields of organosolv pretreated sweetgum (OPSG) and loblolly pine (OPLP) from 49.

Characterization of a novel GH2 family α-L-arabinofuranosidase from hyperthermophilic bacterium Thermotoga thermarum.

The 2,367-bp ORF of TtAFase from Thermotoga thermarum DSM 5069 encodes a calculated 90-kDa α-L-arabinofuranosidase (TtAFase), which does not belonging to any reported glycosyl hydrolase families α-L-arabinofuranosidases in the database and represents a novel one of glycosyl hydrolase family 2. The purified recombinant TtAFase produced in Escherichia coli BL21 (DE3) had optimum activity at pH 5.5 and at 80 °C.

Remarkable solvent and extractable lignin effects on enzymatic digestibility of organosolv pretreated hardwood.

Low solvent concentration effect on substrate digestibility of ethanol organosolv pretreated sweetgum was examined. Surprisingly, lower ethanol concentration in organosolv pretreatments resulted in faster initial rates and higher 72h hydrolysis yields in pretreated substrates. A strong correlation (r(2)=0.

Inhibitory activity of carbonyl compounds on alcoholic fermentation by Saccharomyces cerevisiae.

Aldehydes and acids play important roles in the fermentation inhibition of biomass hydrolysates. A series of carbonyl compounds (vanillin, syringaldehyde, 4-hydroxybenzaldehyde, pyrogallol aldehyde, and o-phthalaldehyde) were used to examine the quantitative structure-inhibitory activity relationship of carbonyl compounds on alcoholic fermentation, based on the glucose consumption rate and the final ethanol yield. It was observed that pyrogallol aldehyde and o-phthalaldehyde (5.

A comparison of three pH control methods for revealing effects of undissociated butyric acid on specific butanol production rate in batch fermentation of Clostridium acetobutylicum.

pH control has been essential for butanol production with Clostridium acetobutylicum. However, it is not very clear at what pH level the acid crash will occur, at what pH level butanol production will be dominant, and at what pH level butyric acid production will be prevailing. Furthermore, contradictory results have been reported about required acidic conditions for initiation of solventogenesis.

Distinct roles of residual xylan and lignin in limiting enzymatic hydrolysis of organosolv pretreated loblolly pine and sweetgum.

The interactions between xylan/lignin and cellulase enzymes play a key role in the effective hydrolysis of lignocellulosic biomass. Organosolv pretreated loblolly pine (OPLP) and sweetgum (OPSG) were used to quantitatively elucidate the distinct roles of residual xylan and lignin on enzymatic hydrolysis, based on the initial hydrolysis rates and the final hydrolysis yields. The initial hydrolysis rates of OPLP and OPSG were 1.

Production of hydrocarbon fuels from biomass using catalytic pyrolysis under helium and hydrogen environments.

This study is focused on hydrocarbon production through changing carrier gas and using zeolite catalysts during pyrolysis. A large reduction in high molecular weight, oxygenated compounds was noticed when the carrier gas was changed from helium to hydrogen during pyrolysis. A catalytic pyrolysis was conducted using two different methods based on how the biomass and catalysts were contacted together.

Improvement in HPLC separation of acetic acid and levulinic acid in the profiling of biomass hydrolysate.

5-Hydroxymethylfurfural (HMF) and furfural could be separated by the Aminex HPX-87H column chromatography, however, the separation and quantification of acetic acid and levulinic acid in biomass hydrolysate have been difficult with this method. In present study, the HPLC separation of acetic acid and levulinic acid on Aminex HPX-87H column has been investigated by varying column temperature, flow rate, and sulfuric acid content in the mobile phase. The column temperature was found critical in resolving acetic acid and levulinic acid.