Sugarcane bagasse (SCB) has a recalcitrant structure, which hinders its component dismantling and subsequent high value utilization. Some organic solvents are favorable to dismantle lignocellulose, but their high viscosity prevents separation of components and reuse of solvents. Herein, ethylene glycol phenyl ether (EGPE)-acid system is used as an example to develop green and efficient methods to dismantle SCB, purify polysaccharides and lignin, and reuse solvents.
View Article and Find Full Text PDFLignin can affect the enzymatic hydrolysis efficiency of lignocellulose. In this study, the lignin isolated from sugarcane bagasse (SCB) pretreated with p-toluenesulfonic acid (PL) was firstly aminated, and then the effects of PL and aminated PL (APL) on the bagasse enzymatic hydrolysis efficiency (EHE) were investigated. The results showed that the addition of PL and APL promoted the EHE, and EHE with APL (73.
View Article and Find Full Text PDFEffective fractionation of lignocelluosic biomass and subsequent valorization of all three major components under mild conditions were achieved. Pretreatment with acidified monophasic phenoxyethanol (EPH) efficiently removed 92.6 % lignin and 80 % xylan from poplar at 110 °C in 60 min, yielding high-value EPH-xyloside, EPH-modified lignin (EPHL), and a solid residue nearly purely composed of carbohydrates.
View Article and Find Full Text PDFThis study identified the intrinsic relationships among slurry rheology, particle characteristics, and lignocellulosic liquefaction/saccharification based on correlation analysis and principal component analysis during the hydrolysis of sugarcane bagasse pretreated by deep eutectic solvents (DES) and mechanical milling (MM). The DES-MM pretreated lignocellulosic slurry (20% solids) exhibited high apparent viscosity of 1.4 × 10 Pa·s and shear stress of 929.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2024
Cellulosic bioethanol production generally has a higher operating cost due to relatively expensive pretreatment strategies and low efficiency of enzymatic hydrolysis. The production of other high-value chemicals such as xylitol and phenylacetylcarbinol (PAC) is, thus, necessary to offset the cost and promote economic viability. The optimal conditions of diluted sulfuric acid pretreatment under boiling water at 95°C and subsequent enzymatic hydrolysis steps for sugarcane bagasse (SCB), rice straw (RS), and corn cob (CC) were optimized using the response surface methodology via a central composite design to simplify the process on the large-scale production.
View Article and Find Full Text PDFPhenylacetylcarbinol (PAC) is a precursor for the synthesis of several pharmaceuticals, including ephedrine, pseudoephedrine, and norephedrine. PAC is commonly produced through biotransformation using microbial pyruvate decarboxylase (PDC) in the form of frozen-thawed whole cells. However, the lack of microorganisms capable of high PDC activity is the main factor in the production of PAC.
View Article and Find Full Text PDFOpen burning of agricultural residues causes numerous complications including particulate matter pollution in the air, soil degradation, global warming and many more. Since they possess bio-conversion potential, agro-industrial residues including sugarcane bagasse (SCB), rice straw (RS), corncob (CC) and sweet sorghum bagasse (SSB) were chosen for the study. Yeast strains, Candida tropicalis, C.
View Article and Find Full Text PDFTo obtain lignin from lignocellulosic biomass, phenoxyethanol (EPH) was employed to construct a biphasic solvent system. The concentration of EPH in this biphasic solvent system was first studied to determine a pretreatment condition for fractionation of lignin. Then, the fractionation of lignin from rice straw was performed under the conditions of temperature 130 °C, cooking time 60 min and sulfuric acid concentration 0.
View Article and Find Full Text PDFA novel method based on pretreatment severity and solvent effects on delignification, was introduced to pretreat and fractionate lignocellulose in a 2-phenoxyethanol (EPH) biphasic solvent system. The combined severity factor (CSF) was used to regulate pretreatment severity, and the relative energy difference (RED) of solvent system to lignin was used to evaluate solvent effects. The combined action of pretreatment severity and solvent effects on delignification was first investigated by the response surface regression analysis on the pretreatment of Amorpha.
View Article and Find Full Text PDFBioresour Bioprocess
September 2022
Unlabelled: The enhanced hydrolysis of xylan-type hemicellulose is important to maximize ethanol production yield and substrate utilization rate in lignocellulose-based simultaneous saccharification and co-fermentation system. In this study, we conduct δ-integration CRISPR Cas9 to achieve multicopy chromosomal integration with high efficiency of reductase–xylitol dehydrogenase pathway in . Subsequently, we devise a consolidated bioprocessing-enabling consortium, in which every engineered yeast strain could secrete or display different assembly components to be adaptively assembled on the surface of scaffoldin-displaying yeast cell for synergistic catalysis and co-fermentation from steam-exploded .
View Article and Find Full Text PDFA novel ternary solvent system for organosolv fractionation of lignocellulosic biomass, named APW process, which is composed of acetone, phenoxyethanol and water with the advantages of monophasic deconstruction and biphasic separation of components was developed. Through fractionation of amorpha as a case study, a monophasic APW solution (acetone/phenoxyethanol/water = 5:11:4, volume ratio) with the best lignin affinity was constructed based on Hansen solubility parameters. According to Taguchi experimental design, the optimal conditions were 130 °C, 70 min, 0.
View Article and Find Full Text PDFReduction in the adsorption of cellulase onto lignin has been thought to be the common reason for the improvement of enzymatic hydrolysis of lignocellulose (EHLC) by a nonionic surfactant (NIS). Few research studies have focused on the relationship between lignocellulosic features and NIS for improving EHLC. This study investigated the impact of Tween20 on the enzymatic hydrolysis and enzyme adsorption of acid-treated and alkali-treated sugarcane bagasse (SCB), cypress, and (PS) with and without being ground.
View Article and Find Full Text PDFIn this work, Spirulina platensis cells harvested in the exponential and equilibrium phases with intact and broken cell walls were treated through a set of alkaline or acidic conditions including alkalis and acids, with solutions of pH 0.0-14.0.
View Article and Find Full Text PDFIn this work, porous cross-linked enzyme aggregates (p-CLEAs) were synthesized by the co-precipitation method using CaCO microparticles as templates. The preparation procedure involved the immobilization of crude lipase as CLEAs precipitation with ammonium sulfate and entrapping these lipase molecules into the CaCO templates, followed by DTT (dithiothreitol)-induced assembly of lipase molecules to form lipase microparticles (lipase molecules were assembled into microparticles internally using disulfide bonds within the lipase molecules as the molecular linkers and stimulated by dithiothreitol); finally, the removal of CaCO templates was performed by EDTA to form pores in CLEAs. The scanning electron microscopy analysis of p-CLEAs showed a porous structure.
View Article and Find Full Text PDFA low-temperature sodium hydroxide (NaOH) pretreatment for sugarcane bagasse (SCB) was obtained via the surface response design in this study. However, a large quantity of water consumption and wastewater generation which have been the common problems for alkaline pretreatment of lignocellulose still exists in this pretreatment. In order to reduce water consumption and wastewater generation, this study attempted to perform enzymatic hydrolysis and fermentation of NaOH-treated SCB without washing process.
View Article and Find Full Text PDFHere, the potential use of herbal residues of Akebia as feedstock for ethanol production is evaluated. Additionally, five deep eutectic solvents from hemicellulose-derived acids were prepared to overcome biomass recalcitrance. Reaction temperatures had more significant influences on solid loss and chemical composition than the molar ratios of choline chloride (ChCl) to derived acids.
View Article and Find Full Text PDFThe black liquor (BL) generated in the alkaline pretreatment process is usually thought as the environmental pollutant. This study found that the pure alkaline lignin hardly inhibited the enzymatic hydrolysis of cellulose (EHC), which led to the investigation on the feasibility of reusing BL as the buffer via pH adjustment for the subsequent enzymatic hydrolysis and fermentation. The pH value of BL was adjusted from 13.
View Article and Find Full Text PDFA process for co-extraction of soluble and insoluble sugars from energy sorghum (ES) was developed based on hydrothermal hydrolysis (HH). Two series of ES were investigated: one (N) with a high biomass yield displayed a higher recalcitrance to sugar release, whereas the second (T) series was characterized by high sugar extraction. The highest total xylose recoveries of 87.
View Article and Find Full Text PDFDuring liquid hot water (LHW) pretreatment, lignin is mostly retained in the pretreated biomass, and the changes in the chemical and structural characteristics of lignin should probably refer to re-/depolymerization, solubilization, or glass transition. The residual lignin could influence the effective enzymatic hydrolysis of cellulose. The pure lignin was used to evaluate the effect of LHW process on its structural and chemical features.
View Article and Find Full Text PDFThe generation of a great quantity of black liquor (BL) and waste wash water (WWW) has been key problems of the alkaline pretreatment. This work tried to build a sustainable way to recycle the BL for pretreating sugarcane bagasse (SCB) and the WWW for washing the residual solid (RS) of alkali-treated SCB which would be subsequently hydrolysed and fermented. The enzymatic hydrolysis efficiency of the washed RS decreased with the recycling times of BL and WWW increasing.
View Article and Find Full Text PDFInt J Biol Macromol
January 2016
Lignin layers surrounding hemicelluloses and cellulose in the plant cell walls protect them from deconstruction. This recalcitrance to sugar release is a major limitation for cost-effective industrial conversion of lignocellulosic biomass to biofuels. Many literatures had reported the contribution of lignin removal to cellulose accessibility to enzyme, but less to the hemicellulose hydrolysis.
View Article and Find Full Text PDFPretreatment is an essential prerequisite to overcome recalcitrance of biomass and enhance the ethanol conversion efficiency of polysaccharides. Compared with other pretreatment methods, liquid hot water (LHW) pretreatment not only reduces the downstream pressure by making cellulose more accessible to the enzymes but minimizes the formation of degradation products that inhibit the growth of fermentative microorganisms. Herein, this review summarized the improved LHW process for different biomass feedstocks, the decomposition behavior of biomass in the LHW process, the enzymatic hydrolysis of LHW-treated substrates, and production of high value-added products and ethanol.
View Article and Find Full Text PDFPennisetum hybrid I, II and switchgrass were pretreated with liquid hot water to enhance the release of sugars. The optimum hydrolysis factor for three energy grasses was 5.98, and the total xylose yield was 88.
View Article and Find Full Text PDFIn the process of liquid hot water (LHW) pretreatment, there are numbers of pellets formed on the lignocellulosic surface. The characteristics and effect of pellets on the enzymatic hydrolysis of LHW-treated sugarcane bagasse (SCB) were investigated. After SCB was treated with LHW at 180°C, the pellets deposited on the surface of solid residues were extracted gently with 1% sodium hydroxide (NaOH) solution.
View Article and Find Full Text PDFMicrob Biotechnol
September 2015
Metagenomics analysis has been applied to identify the dominant anaerobic microbial consortium of the carbon monoxide (CO) oxidizers in anaerobic sludge. Reads from the hypervariable V6 region in the bacterial 16s rDNA were aligned and finally clustered into operational taxonomic units (OTUs). The OTUs from different stages in anaerobic CO condition were classified.
View Article and Find Full Text PDF