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Bu L.,Beijing Forestry University | Tang Y.,Beijing Forestry University | Xing Y.,Beijing Forestry University | Zhang W.,Nanjing Academy of Wild Plant | And 2 more authors.
Bioscience, Biotechnology and Biochemistry

Furfural residue (FR) is a waste lignocellulosic material with enormous potential for bioethanol production. In this study, bioethanol production from FR after delignification was compared. Hydrophilic variation was measured by conductometric titration to detect the relationship between hydrophilicity and bioethanol production. It was found that ethanol yield increased as delignification enhanced, and it reached up to 75.6% of theoretical yield for samples with 8.7% lignin. The amount of by-products decreased as delignification increased. New inflection points appeared in conductometric titration curves of samples that were partially delignified, but they vanished in the curves of the highly delignified samples. Total charges and carboxyl levels increased after slight delignification, and they decreased upon further delignification. These phenomena suggested some new hydrophilic groups were formed during pretreated delignification, which would be beneficial to enzymatic hydrolysis. However, some newly formed groups may act as toxicant to the yeast during simultaneous saccharification and fermentation. © 2014 Japan Society for Bioscience, Biotechnology, and Agrochemistry. Source

Tang Y.,Beijing Forestry University | Zhu L.,Beijing Forestry University | Zhang W.,Nanjing Academy of Wild Plant | Shang X.,Chunlei Industrial Group Co. | Jiang J.,Beijing Forestry University
Applied Microbiology and Biotechnology

The sequential production of bioethanol and lactic acid from starch materials and lignocellulosic materials was investigated as ethanol fermentation broth (EFB) can provide nutrients for lactic acid bacteria. A complete process was developed, and all major operations are discussed, including ethanol fermentation, broth treatment, lactic acid fermentation, and product separation. The effect of process parameters, including ethanol fermentation conditions, treatment methods, and the amount of EFB used in simultaneous saccharification and fermentation (SSF), is investigated. Under the selected process conditions, the integrated process without additional chemical consumption provides a 1.08 acid/alcohol ratio (the broth containing 22.4 g/L ethanol and 47.6 g/L lactic acid), which corresponds to a polysaccharide utilization ratio of 86.9 %. Starch ethanol can thus promote cellulosic lactic acid by providing important nutrients for lactic acid bacteria, and in turn, cellulosic lactic acid could promote starch ethanol by improving the profit of the ethanol production process. Two process alternatives for the integration of starch ethanol and cellulosic lactic acid are compared, and some suggestions are given regarding the reuse of yeast following the cellulosic SSF step for lactic acid production. © 2012 Springer-Verlag Berlin Heidelberg. Source

Xing Y.,Beijing Forestry University | Ji L.,Beijing Forestry University | Liu Z.-P.,Chunlei Industrial Group Co. | Zhang W.-M.,Nanjing Academy of Wild Plant | Jiang J.-X.,Beijing Forestry University
Industrial Crops and Products

Surfactants are popular additives for the prevention of the inhibitory effect of lignin on cellulolytic enzymes. Saponin is a type of natural surfactant extracted from Gleditsia spp. In this study, the effect of saponin on the high-solids-loading enzymatic hydrolysis of furfural residues (FRs) with a lignin content of 45% was investigated. The optimal dosage of Gleditsia saponin (GS) was determined to be 25-fold greater than its critical micelle concentration (CMC; 0.16. g/L). The addition of GS increased the cellulose conversion by up to 52.63% in high-solids-loading enzymatic hydrolysis. Due to the addition of GS, a maximum cellulose conversion of 74.88% was achieved after FRs had hydrolyzed for 120. h at a solids loading of 20% (w/w) with 30 filter paper unit (FPU)/g-cellulose. The decrease in cellulose conversion was found to exhibit a linear correlation with an increase in the solids loadings from 20.0% to 27.5% (w/w). The surface structural variations of hydrolytic residues were characterized by X-ray photoelectron spectroscopy (XPS). The results indicated that the carbonyl groups of lignin facilitated the binding of GS to the surface of lignin, which resulted in a decrease in the adsorption of between the enzyme and lignin. Interestingly, GS could maintain enzymatic activity in the supernatants. © 2014 Elsevier B.V. Source

Yang H.,Beijing Forestry University | Wang K.,Beijing Forestry University | Xu F.,Beijing Forestry University | Sun R.-C.,Beijing Forestry University | And 2 more authors.
Industrial and Engineering Chemistry Research

Sealed structure of plant biomass resists assault on cellulose from enzymatic deconstruction. In this study, pretreatments of triploid poplar were conducted with 0.5 wt % H 2SO 4 at various temperatures (100-200 °C) to loosen the intricate structure. The effect of temperature on cellulose structure and enzymatic digestibility was evaluated. The results indicated that the effective removal of hemicelluloses and amorphous cellulose incurred the increment of crystalline indices of residues. Companied with the degradation of carbohydrates, inhibitory compounds were accumulated with the increasing severity. On the whole, 120 °C was considered as the optimum temperature by taking the balance between substrate digestibility and recovery into account. © 2012 American Chemical Society. Source

Ji L.,Beijing Forestry University | Yu H.,Beijing Forestry University | Liu Z.,Chunlei Industrial Group Co. | Jiang J.,Beijing Forestry University | Sun D.,Nanjing Institute for the Comprehensive Utilization of Wild Plant

Simultaneous saccharification and fermentation (SSF) is an attractive process configuration for bio-ethanol production. Further reductions in process cost of SSF are expected with the use of waste agricultural or industrial materials as feedstock. In the current study, two industrial lignocellulosic wastes, cassava residues (CR) and furfural residues (FR), were combined during SSF for ethanol production due to their value-added applications and positive environmental impacts. After CR were liquefied and saccharified, saccharification liquid was added to SSF of FR. The effect of substrate fractions was investigated in terms of ethanol yield, byproduct concentration and the number of yeast cells. Besides, a natural surfactant, Gleditsia saponin, was added to investigate the effect of FR lignin on SSF with 20% substrate concentration. The results showed that increasing the ratio of CR/FR improved the ethanol yield and that the ethanol yield was also increased gradually by increasing the substrate concentration from 6% to 12%. A high ethanol concentration of 36.0 g/L was obtained under the condition of CR:FR = 2:1 with 12% substrate concentration, reaching 71.1% of the theoretical yield. However, Gleditsia saponin did not affect the ethanol yield, indicating the insignificant effect of lignin in SSF with low lignin content in the reaction system. Source

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