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Sample records for reesei enzymatic hydrolysis

  1. Enzymatic hydrolysis of cocoa pod husks. [Trichoderma reesei

    SciTech Connect

    Simpson, B.K.; Oldham, J.H.; Martin, A.M

    1984-07-01

    Laboratory results are presented of the bioconversion of cellulose from cocoa pod husks, utilizing cellulase from three mutants of Trichoderma reesei. Total reducing sugars in filtered hydrolysates were estimated by the dinitrosalicylic acid method. The sugars present were identified by paper chromatography as glucose and xylose.

  2. Precipitation of Trichoderma reesei commercial cellulase preparations under standard enzymatic hydrolysis conditions for lignocelluloses.

    PubMed

    Chylenski, Piotr; Felby, Claus; Østergaard Haven, Mai; Gama, Miguel; Selig, Michael J

    2012-08-01

    Comparative studies between commercial Trichoderma reesei cellulase preparations show that, depending on the preparation and loading, total protein precipitation can be as high as 30 % under standard hydrolysis conditions used for lignocellulosic materials. ATR-IR and SDS-PAGE data verify precipitates are protein-based and contain key cell wall hydrolyzing enzymes. Precipitation increased considerably with incubation temperature; roughly 50-150 % increase from 40 to 50 °C and 800 % greater at 60 °C. All of the reported protein losses translated into significant, and often drastic, losses in activity on related 4-nitrophenyl substrates. In addition, supplementation with the non-ionic surfactant PEG 6,000 decreased precipitation up to 80 % in 24 h precipitation levels. Protein precipitation is potentially substantial during enzymatic hydrolysis of lignocelluloses and should be accounted for during lignocellulose conversion process design, particularly when enzyme recycling is considered.

  3. Enzymatic hydrolysis of cellulose in aqueous two-phase systems. 1. Partition of cellulases from Trichoderma reesei

    SciTech Connect

    Tjerneld, F.; Persson, J.; Albertsson, P.A.; Hahn-Haegerdal, B.

    1985-07-01

    The partitioning of endo-..beta..-glucanase, exo-..beta..-glucananse, and ..beta..-glucosidase from Trichoderma reesei QM 9414 in aqueous two-phase systems has been studied with the object of designing a phase system for continuous bioconversion of cellulose. The partitioning of the enzymes in two-phase systems composed of various water soluble polymeric compounds were studied. Systems based on dextran and polyethylene glycol (PEG) were optimal for one sidedly partitioning of the enzymes to the bottom phase. The influence of polymer molecular weights, polymer concentration, ionic composition of the medium, pH, temperature, and adsorption of the enzymes to cellulose on the enyzme partition coefficients (K) were studied. By combining the effects of polymer molecular weight and adsorption to cellulose, K values could be reduced for endo-..beta..-glucanase to 0.02 and for ..beta..-glucosidase to 0.005 at 20 degrees C in a phase system of Dvalues could be reduced for endo-..beta..-glucanase to 0.02 and for ..beta..-glucosidase to 0.005 at 20 degrees C in a phase system of Dextran 40-PEG 40000 in the presence of excess cellulose. At 50 degrees C, K values were increased by a factor of two. In a phase system based on inexpensive crude dextran and PEG, the partition coefficient for endo-..beta..-glucanase was 0.16 and for beta-glucosidase was 0.14 at 20 degrees C with excess cellulose present.

  4. Pretreatment and Enzymatic Hydrolysis

    SciTech Connect

    2006-06-01

    Activities in this project are aimed at overcoming barriers associated with high capital and operating costs and sub-optimal sugar yields resulting from pretreatment and subsequent enzymatic hydrolysis of biomass.

  5. Enzymatic hydrolysis and fermentation of agricultural residues to ethanol

    SciTech Connect

    Mes-Hartree, M.; Hogan, C.M.; Saddler, J.N.

    1984-01-01

    A combined enzymatic hydrolysis and fermentation process was used to convert steam-treated wheat and barley straw to ethanol. Maximum conversion efficiencies were obtained when the substrates were steamed for 90 s. These substrates could yield over 0.4 g ethanol/g cellulose following a combined enzymatic hydrolysis and fermentation process procedure using culture filtrates derived from Trichoderma harzianum E58. When culture filtrates from Trichoderma reesei C30 and T. reesei QM9414 were used, the ethanol yields obtained were 0.32 and 0.12 g ethanol/g cellulose utilized, respectively. The lower ethanol yields obtained with these strains were attributed to the lower amounts of ..beta..-glucosidase detected in the T. reesei culture filtrates.

  6. Kinetics of cellobiose hydrolysis using cellobiase composites from Trichoderma reesei and Aspergillus niger

    SciTech Connect

    Grous, W.; Converse, A.; Grethlein, H.; Lynd, L.

    1985-01-01

    The enzymatic hydrolysis of cellulose to glucose involves the formation of cellobiose as an intermediate. It has been found necessary to add cellobiase from Aspergillus niger (NOVO) to the cellobiase component of Trichoderma reesei mutant Rut C-30 (Natick) cellulase enzymes in order to obtain after 48 h complete conversion of the cellobiose formed in the enzymatic hydrolysis of biomass. This study of the cellobiase activity of these two enzyme sources was undertaken as a first step in the formation of a kinetic model for cellulose hydrolysis that can be used in process design. In order to cover the full range of cellobiose concentrations, it was necessary to develop separate kinetic parameters for high- and low-concentration ranges of cellobiose for the enzymes from each organism. Competitive glucose inhibition was observed with the enzymes from both organisms. Substrate inhibition was observed only with the A. niger enzymes.

  7. Enzymatic hydrolyzing performance of Acremonium cellulolyticus and Trichoderma reesei against three lignocellulosic materials.

    PubMed

    Fujii, Tatsuya; Fang, Xu; Inoue, Hiroyuki; Murakami, Katsuji; Sawayama, Shigeki

    2009-10-01

    Bioethanol isolated from lignocellulosic biomass represents one of the most promising renewable and carbon neutral alternative liquid fuel sources. Enzymatic saccharification using cellulase has proven to be a useful method in the production of bioethanol. The filamentous fungi Acremonium cellulolyticus and Trichoderma reesei are known to be potential cellulase producers. In this study, we aimed to reveal the advantages and disadvantages of the cellulase enzymes derived from these fungi. We compared A. cellulolyticus and T. reesei cellulase activity against the three lignocellulosic materials: eucalyptus, Douglas fir and rice straw. Saccharification analysis using the supernatant from each culture demonstrated that the enzyme mixture derived from A. cellulolyticus exhibited 2-fold and 16-fold increases in Filter Paper enzyme and beta-glucosidase specific activities, respectively, compared with that derived from T. reesei. In addition, culture supernatant from A. cellulolyticus produced glucose more rapidly from the lignocellulosic materials. Meanwhile, culture supernatant derived from T. reesei exhibited a 2-fold higher xylan-hydrolyzing activity and produced more xylose from eucalyptus (72% yield) and rice straw (43% yield). Although the commercial enzymes Acremonium cellulase (derived from A. cellulolyticus, Meiji Seika Co.) demonstrated a slightly lower cellulase specific activity than Accellerase 1000 (derived from T. reesei, Genencor), the glucose yield (over 65%) from lignocellulosic materials by Acremonium cellulase was higher than that of Accellerase 1000 (less than 60%). In addition, the mannan-hydrolyzing activity of Acremonium cellulase was 16-fold higher than that of Accellerase 1000, and the conversion of mannan to mannobiose and mannose by Acremonium cellulase was more efficient. We investigated the hydrolysis of lignocellulosic materials by cellulase derived from two types of filamentous fungi. We found that glucan-hydrolyzing activity of the culture

  8. Linking hydrolysis performance to Trichoderma reesei cellulolytic enzyme profile.

    PubMed

    Lehmann, Linda; Rønnest, Nanna P; Jørgensen, Christian I; Olsson, Lisbeth; Stocks, Stuart M; Jørgensen, Henrik S; Hobley, Timothy

    2016-05-01

    Trichoderma reesei expresses a large number of enzymes involved in lignocellulose hydrolysis and the mechanism of how these enzymes work together is too complex to study by traditional methods, for example, by spiking with single enzymes and monitoring hydrolysis performance. In this study, a multivariate approach, partial least squares regression, was used to see whether it could help explain the correlation between enzyme profile and hydrolysis performance. Diverse enzyme mixtures were produced by T. reesei Rut-C30 by exploiting various fermentation conditions and used for hydrolysis of washed pretreated corn stover as a measure of enzyme performance. In addition, the enzyme mixtures were analyzed by liquid chromatography-tandem mass spectrometry to identify and quantify the different proteins. A multivariate model was applied for the prediction of enzyme performance based on the combination of different proteins present in an enzyme mixture. The multivariate model was used for identification of candidate proteins that are correlated to enzyme performance on pretreated corn stover. A very large variation in hydrolysis performance was observed and this was clearly caused by the difference in fermentation conditions. Besides β-glucosidase, the multivariate model identified several xylanases, Cip1 and Cip2, as relevant proteins to study further.

  9. Production of rice straw hydrolysis enzymes by the fungi Trichoderma reesei and Humicola insolens using rice straw as a carbon source.

    PubMed

    Kogo, Takashi; Yoshida, Yuki; Koganei, Keisuke; Matsumoto, Hitoshi; Watanabe, Taisuke; Ogihara, Jun; Kasumi, Takafumi

    2017-02-11

    Rice straw was evaluated as a carbon source for the fungi, Trichoderma reesei and Humicola insolens, to produce enzymes for rice straw hydrolysis. The enzyme activity of T. reesei and H. insolens cultivated in medium containing non-treated rice straw were almost equivalent to the enzyme of T. reesei cultivated in Avicel medium, a form of refined cellulose. The enzyme activity of T. reesei cultivated in medium containing NH4OH-treated rice straw was 4-fold higher than enzyme from cultures grown in Avicel medium. In contrast, H. insolens enzyme from cultures grown in NH4OH-treated rice straw had significantly lower activity compared with non-treated rice straw or Avicel. The combined use of T. reesei and H. insolens enzymes resulted in a significant synergistic enhancement in enzymatic activity. Our data suggest that rice straw is a promising low-cost carbon source for fungal enzyme production for rice straw hydrolysis.

  10. Enzymatic hydrolysis of cellulose and various pretreated wood fractions

    SciTech Connect

    Saddler, J.N.; Brownell, H.H.; Clermont, L.P.; Levitin, N.

    1982-06-01

    Three strains of Trichoderma-Trichoderma reesei C30, Trichoderma reesei QM9414, and Trichoderma species E58-were used to study the enzymatic hydrolysis of pretreated wood substrates. Each of the culture filtrates was incubated with a variety of commercially prepared cellulose substrates and pretreated wood substrates. Solka floc was the most easily degraded commercial cellulose. The enzyme accessibility of steam-exploded samples which has been alkali extracted and then stored wet decreased with the duration of the steam treatment. Air drying reduced the extent of hydrolysis of all the samples but had a greater effect on the samples which had previously shown the greatest hydrolysis. Mild pulping using 2% chlorite increased the enzymatic hydrolysis of all the samples. Steam explosion was shown to be an excellent pretreatment method for aspen wood and was much superior to dilute nitric acid pretreatment. The results indicate that the distribution of the lignin as well as the surface area of the cellulosic substrate are important features in enzymatic hydrolysis. (Refs 17).

  11. Enzymatic Hydrolysis of Cellulosic Biomass

    SciTech Connect

    Yang, Bin; Dai, Ziyu; Ding, Shi-You; Wyman, Charles E.

    2011-08-22

    Biological conversion of cellulosic biomass to fuels and chemicals offers the high yields to products vital to economic success and the potential for very low costs. Enzymatic hydrolysis that converts lignocellulosic biomass to fermentable sugars may be the most complex step in this process due to substrate-related and enzyme-related effects and their interactions. Although enzymatic hydrolysis offers the potential for higher yields, higher selectivity, lower energy costs, and milder operating conditions than chemical processes, the mechanism of enzymatic hydrolysis and the relationship between the substrate structure and function of various glycosyl hydrolase components are not well understood. Consequently, limited success has been realized in maximizing sugar yields at very low cost. This review highlights literature on the impact of key substrate and enzyme features that influence performance to better understand fundamental strategies to advance enzymatic hydrolysis of cellulosic biomass for biological conversion to fuels and chemicals. Topics are summarized from a practical point of view including characteristics of cellulose (e.g., crystallinity, degree of polymerization, and accessible surface area) and soluble and insoluble biomass components (e.g., oligomeric xylan, lignin, etc.) released in pretreatment, and their effects on the effectiveness of enzymatic hydrolysis. We further discuss the diversity, stability, and activity of individual enzymes and their synergistic effects in deconstructing complex lignocellulosic biomass. Advanced technologies to discover and characterize novel enzymes and to improve enzyme characteristics by mutagenesis, post-translational modification, and over-expression of selected enzymes and modifications in lignocellulosic biomass are also discussed.

  12. Enzymatic hydrolysis of organic phosphorus

    USDA-ARS?s Scientific Manuscript database

    Orthophosphate-releasing enzymatic hydrolysis is an alternative means for characterizing organic phosphorus (Po) in animal manure. The approach is not only simple and fast, but can also provide information difficult to obtain by other methods. Currently, commercially available phosphatases are mainl...

  13. Influence of major structural features of cellulose on rate of enzymatic hydrolysis

    SciTech Connect

    Fan, L.T.; Lee, Y.H.; Beardmore, D.R.

    1981-02-01

    An attempt was made to determine the effect of two structural features of cellulose on its enzymatic hydrolysis: its crystallinity and its specific surface area. Solka Floc SW40 was pretreated in various ways prior to hydrolysis: ball milling, gamma radiation, pyrolysis, treatment by sodium hydroxide, treatment by CMCS, and treatment by sulfuric acid. Microcrystalline cellulose (Sigmacell 50) was also employed in the test. The culture filtrate of Trichoderma reesei QM9414 was the source of the enzyme. It was observed that, independent of the methods of treatment, the rate of hydrolysis would tend to increase with an increase in specific surface area and with a decrease in crystallinity index.

  14. Monitoring enzymatic ATP hydrolysis by EPR spectroscopy.

    PubMed

    Hacker, Stephan M; Hintze, Christian; Marx, Andreas; Drescher, Malte

    2014-07-14

    An adenosine triphosphate (ATP) analogue modified with two nitroxide radicals is developed and employed to study its enzymatic hydrolysis by electron paramagnetic resonance spectroscopy. For this application, we demonstrate that EPR holds the potential to complement fluorogenic substrate analogues in monitoring enzymatic activity.

  15. Alkaline peroxide delignification of agricultural residues to enhance enzymatic saccharification. [Trichoderma reesei

    SciTech Connect

    Gould, J.M.

    1984-01-01

    Approximately one-half of the lignin and most of the hemicellulose present in agricultural residues such as wheat straw and corn stover are solubilized when the residue is treated at 25/sup 0/C in an alkaline solution of hydrogen peroxide. The delignification reaction is most efficient when the ratio of hydrogen peroxide to substrate is at least 0.25 (w/w) and the pH is 11.5. The supernatant fraction from a given pretreatment, after addition of makeup peroxide and readjustment of the pH, can be recycled to treat at least six additional batches of substrate, resulting in a substantial concentration of hemicellulose and soluble lignin degradation products. Hydrolysis of the insoluble fraction with Trichoderma reesei cellulase after alkline peroxide treatment yields glucose with almost 100% efficiency, based upon the cellulose content of the residue before treatment. These data indicate that alkaline peroxide pretreatment is a simple and efficient method for enhancing the enzymatic digestibility of lignocellulosic crop residues to levels approaching the theoretical maximum.

  16. Review: Enzymatic Hydrolysis of Cellulosic Biomass

    SciTech Connect

    Yang, Bin; Dai, Ziyu; Ding, Shi-You; Wyman, Charles E.

    2011-07-16

    Biological conversion of cellulosic biomass to fuels and chemicals offers the high yields to products vital to economic success and the potential for very low costs. Enzymatic hydrolysis that converts lignocellulosic biomass to fermentable sugars may be the most complex step in this process due to substrate-related and enzyme-related effects and their interactions. Although enzymatic hydrolysis offers the potential for higher yields, higher selectivity, lower energy costs, and milder operating conditions than chemical processes, the mechanism of enzymatic hydrolysis and the relationship between the substrate structure and function of various glycosyl hydrolase components are not well understood. Consequently, limited success has been realized in maximizing sugar yields at very low cost. This review highlights literature on the impact of key substrate and enzyme features that influence performance to better understand fundamental strategies to advance enzymatic hydrolysis of cellulosic biomass for biological conversion to fuels and chemicals. Topics are summarized from a practical point of view including characteristics of cellulose (e.g., crystallinity, degree of polymerization, and accessible surface area) and soluble and insoluble biomass components (e.g., oligomeric xylan, lignin, etc.) released in pretreatment, and their effects on the effectiveness of enzymatic hydrolysis. We further discuss the diversity, stability, and activity of individual enzymes and their synergistic effects in deconstructing complex lignocellulosic biomass. Advanced technologies to discover and characterize novel enzymes and to improve enzyme characteristics by mutagenesis, post-translational modification, and over-expression of selected enzymes and modifications in lignocellulosic biomass are also discussed.

  17. Enzymatic hydrolysis of lignocellulosic biomass from Onopordum nervosum.

    PubMed

    Martín, C; Negro, M J; Alfonsel, M; Sáez, R

    1988-07-20

    Some properties of the cellulolytic complex obtained from Trichoderma reesei QM 9414 grown on Solka floc as carbon source and its ability to hydrolyze the lignocellulosic biomass of Onopordum nervosum Boiss were studied. The optimum enzyme activity was found at temperatures between 50 and 55 degrees C and pH ranging from 4.3 to 4.8. Hydrolysis of 4-nitropnenyl-beta-D-glucopyranoside (4-NPG) and cellobiose by the beta-glucosidase of the complex, showed competitive inhibition by glucose with a K(i) value of 0.8 mM for 4-NPG and 2. 56 mM for cellobiose. Enzymatic hydrolysis yield of Onopordum nervosum, evaluated as glucose production after 48 h, showed a threefold increase by pretreating the lignocellulosic substrate with alkali. When the loss of glucose incurred by de pretreatment was taken into account, a 160% increase in the final cellulose to glucose conversion was found to be due to the pretreatment.

  18. Enhanced enzymatic hydrolysis of cellulose in microgels.

    PubMed

    Chang, Aiping; Wu, Qingshi; Xu, Wenting; Xie, Jianda; Wu, Weitai

    2015-07-04

    A cellulose-based microgel, where an individual microgel contains approximately one cellulose chain on average, is synthesized via free radical polymerization of a difunctional small-molecule N,N'-methylenebisacrylamide in cellulose solution. This microgelation leads to a low-ordered cellulose, favoring enzymatic hydrolysis of cellulose to generate glucose.

  19. Regenerating cellulose from ionic liquids for an accelerated enzymatic hydrolysis

    SciTech Connect

    Zhao, Hua; Jones, Cecil L; Baker, Gary A; Xia, Shuqian; Olubajo, Olarongbe; Person, Vernecia

    2009-01-01

    The efficient conversion of lignocellulosic materials into fuel ethanol has become a research priority in producing affordable and renewable energy. The pretreatment of lignocelluloses is known to be key to the fast enzymatic hydrolysis of cellulose. Recently, certain ionic liquids (ILs)were found capable of dissolving more than 10 wt% cellulose. Preliminary investigations [Dadi, A.P., Varanasi, S., Schall, C.A., 2006. Enhancement of cellulose saccharification kinetics using an ionic liquid pretreatment step. Biotechnol. Bioeng. 95, 904 910; Liu, L., Chen, H., 2006. Enzymatic hydrolysis of cellulose materials treated with ionic liquid [BMIM]Cl. Chin. Sci. Bull. 51, 2432 2436; Dadi, A.P., Schall, C.A., Varanasi, S., 2007. Mitigation of cellulose recalcitrance to enzymatic hydrolysis by ionic liquid pretreatment. Appl. Biochem. Biotechnol. 137 140, 407 421] suggest that celluloses regenerated from IL solutions are subject to faster saccharification than untreated substrates. These encouraging results offer the possibility of using ILs as alternative and nonvolatile solvents for cellulose pretreatment. However, these studies are limited to two chloride-based ILs: (a) 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), which is a corrosive, toxic and extremely hygroscopic solid (m.p. 70 C), and (b) 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), which is viscous and has a reactive side-chain. Therefore, more in-depth research involving other ILs is much needed to explore this promising pretreatment route. For this reason, we studied a number of chloride- and acetate-based ILs for cellulose regeneration, including several ILs newly developed in our laboratory. This will enable us to select inexpensive, efficient and environmentally benign solvents for processing cellulosic biomass. Our data confirm that all regenerated celluloses are less crystalline (58 75% lower) and more accessible to cellulase (>2 times) than untreated substrates. As a result, regenerated Avicel

  20. Enzymatic hydrolysis of poly(ethylene furanoate).

    PubMed

    Pellis, Alessandro; Haernvall, Karolina; Pichler, Christian M; Ghazaryan, Gagik; Breinbauer, Rolf; Guebitz, Georg M

    2016-10-10

    The urgency of producing new environmentally-friendly polyesters strongly enhanced the development of bio-based poly(ethylene furanoate) (PEF) as an alternative to plastics like poly(ethylene terephthalate) (PET) for applications that include food packaging, personal and home care containers and thermoforming equipment. In this study, PEF powders of various molecular weights (6, 10 and 40kDa) were synthetized and their susceptibility to enzymatic hydrolysis was investigated for the first time. According to LC/TOF-MS analysis, cutinase 1 from Thermobifida cellulosilytica liberated both 2,5-furandicarboxylic acid and oligomers of up to DP4. The enzyme preferentially hydrolyzed PEF with higher molecular weights but was active on all tested substrates. Mild enzymatic hydrolysis of PEF has a potential both for surface functionalization and monomers recycling.

  1. Additives enhancing enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Rocha-Martín, Javier; Martinez-Bernal, Claudio; Pérez-Cobas, Yolanda; Reyes-Sosa, Francisco Manuel; García, Bruno Díez

    2017-11-01

    Linked to the development of cellulolytic enzyme cocktails from Myceliophthora thermophila, we studied the effect of different additives on the enzymatic hydrolysis yield. The hydrolysis of pretreated corn stover (PCS), sugar cane straw (PSCS) and microcrystalline cellulose (Avicel) was performed under industrial conditions using high solid loadings, limited mixing, and low enzyme dosages. The addition of polyethylene glycol (PEG4000) allowed to increase the glucose yields by 10%, 7.5%, and 32%, respectively in the three materials. PEG4000 did not have significant effect on the stability of the main individual enzymes but increased beta-glucosidase and endoglucanase activity by 20% and 60% respectively. Moreover, the presence of PEG4000 accelerated cellulase-catalyzed hydrolysis reducing up to 25% the liquefaction time. However, a preliminary economical assessment concludes that even with these improvements, a lower contribution of PEG4000 to the 2G bioethanol production costs would be needed to reach commercial feasibility. Copyright © 2017. Published by Elsevier Ltd.

  2. Molecular-scale investigations of cellulose microstructure during enzymatic hydrolysis.

    PubMed

    Santa-Maria, Monica; Jeoh, Tina

    2010-08-09

    Changes in cellulose microstructure have been proposed to occur throughout hydrolysis that impact enzyme access and hydrolysis rates. However, there are very few direct observations of such changes in ongoing reactions. In this study, changes in the microstructure of cellulose are measured by simultaneous confocal and atomic force microscopy and are correlated to hydrolysis extents and quantities of bound enzyme in the reaction. Minimally processed and never-dried cellulose I was hydrolyzed by a purified cellobiohydrolase, Trichoderma reesei Cel7A. Early in the reaction ( approximately 30% hydrolysis), at high hydrolysis rates and high bound cellulase quantities, untwisting of cellulose microfibrils was observed. As the hydrolysis reaction neared completion (>80% hydrolysis), extensively thinned microfibrils (diameters of 3-5 nm) and channels (0.3-0.6 nm deep) along the lengths of the microfibrils were observed. The prominent microstructural changes in cellulose due to cellobiohydrolase action are discussed in the context of the overall hydrolysis reaction.

  3. Palm date fibers: analysis and enzymatic hydrolysis.

    PubMed

    Shafiei, Marzieh; Karimi, Keikhosro; Taherzadeh, Mohammad J

    2010-11-01

    Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin) settled easily, while the low-lignin fibers (41.4% lignin) formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes.

  4. Palm Date Fibers: Analysis and Enzymatic Hydrolysis

    PubMed Central

    Shafiei, Marzieh; Karimi, Keikhosro; Taherzadeh, Mohammad J.

    2010-01-01

    Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin) settled easily, while the low-lignin fibers (41.4% lignin) formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes. PMID:21151438

  5. Effects of enzymatic hydrolysis on lentil allergenicity.

    PubMed

    Cabanillas, Beatriz; Pedrosa, Mercedes M; Rodríguez, Julia; González, Angela; Muzquiz, Mercedes; Cuadrado, Carmen; Crespo, Jesús F; Burbano, Carmen

    2010-09-01

    Enzymatic hydrolysis and further processing are commonly used to produce hypoallergenic dietary products derived from different protein sources, such as cow's milk. Lentils and chickpeas seem to be an important cause of IgE-mediated hypersensitivity in the Mediterranean area and India. Some studies have investigated the effects of enzymatic treatments on the in vitro immunological reactivity of members of the Leguminosae family, such as soybean, chickpea, lentil, and lupine. Nevertheless, there are only a few studies carried out to evaluate the effect on IgE reactivity of these food-hydrolysis products with sera from patients with well-documented allergy to these foods. In this study, lentil protein extract was hydrolyzed by sequential action of an endoprotease (Alcalase) and an exoprotease (Flavourzyme). Immunoreactivity to raw and hydrolyzed lentil extract was evaluated by means of IgE immunoblotting and ELISA using sera from five patients with clinical allergy to lentil. The results indicated that sequential hydrolysis of lentil results in an important proteolytic destruction of IgE-binding epitopes shown by in vitro experiments. However, some allergenic proteins were still detected by sera from four out of five patients in the last step of sequential hydrolyzation.

  6. Enzymatic hydrolysis of spent coffee ground.

    PubMed

    Jooste, T; García-Aparicio, M P; Brienzo, M; van Zyl, W H; Görgens, J F

    2013-04-01

    Spent coffee ground (SCG) is the main residue generated during the production of instant coffee by thermal water extraction from roasted coffee beans. This waste is composed mainly of polysaccharides such as cellulose and galactomannans that are not solubilised during the extraction process, thus remaining as unextractable, insoluble solids. In this context, the application of an enzyme cocktail (mannanase, endoglucanase, exoglucanase, xylanase and pectinase) with more than one component that acts synergistically with each other is regarded as a promising strategy to solubilise/hydrolyse remaining solids, either to increase the soluble solids yield of instant coffee or for use as raw material in the production of bioethanol and food additives (mannitol). Wild fungi were isolated from both SCG and coffee beans and screened for enzyme production. The enzymes produced from the selected wild fungi and recombinant fungi were then evaluated for enzymatic hydrolysis of SCG, in comparison to commercial enzyme preparations. Out of the enzymes evaluated on SCG, the application of mannanase enzymes gave better yields than when only cellulase or xylanase was utilised for hydrolysis. The recombinant mannanase (Man1) provided the highest increments in soluble solids yield (17 %), even when compared with commercial preparations at the same protein concentration (0.5 mg/g SCG). The combination of Man1 with other enzyme activities revealed an additive effect on the hydrolysis yield, but not synergistic interaction, suggesting that the highest soluble solid yields was mainly due to the hydrolysis action of mannanase.

  7. Pretreatment and enzymatic hydrolysis of lignocellulosic biomass

    NASA Astrophysics Data System (ADS)

    Corredor, Deisy Y.

    The performance of soybean hulls and forage sorghum as feedstocks for ethanol production was studied. The main goal of this research was to increase fermentable sugars' yield through high-efficiency pretreatment technology. Soybean hulls are a potential feedstock for production of bio-ethanol due to their high carbohydrate content (≈50%) of nearly 37% cellulose. Soybean hulls could be the ideal feedstock for fuel ethanol production, because they are abundant and require no special harvesting and additional transportation costs as they are already in the plant. Dilute acid and modified steam-explosion were used as pretreatment technologies to increase fermentable sugars yields. Effects of reaction time, temperature, acid concentration and type of acid on hydrolysis of hemicellulose in soybean hulls and total sugar yields were studied. Optimum pretreatment parameters and enzymatic hydrolysis conditions for converting soybean hulls into fermentable sugars were identified. The combination of acid (H2SO4, 2% w/v) and steam (140°C, 30 min) efficiently solubilized the hemicellulose, giving a pentose yield of 96%. Sorghum is a tropical grass grown primarily in semiarid and dry parts of the world, especially in areas too dry for corn. The production of sorghum results in about 30 million tons of byproducts mainly composed of cellulose, hemicellulose, and lignin. Forage sorghum such as brown midrib (BMR) sorghum for ethanol production has generated much interest since this trait is characterized genetically by lower lignin concentrations in the plant compared with conventional types. Three varieties of forage sorghum and one variety of regular sorghum were characterized and evaluated as feedstock for fermentable sugar production. Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and X-Ray diffraction were used to determine changes in structure and chemical composition of forage sorghum before and after pretreatment and enzymatic hydrolysis

  8. Enhanced enzymatic hydrolysis of waste paper for ethanol production using separate saccharification and fermentation.

    PubMed

    Guerfali, Mohamed; Saidi, Adel; Gargouri, Ali; Belghith, Hafedh

    2015-01-01

    Ethanol produced from lignocellulosic biomass is a renewable alternative to diminishing petroleum-based liquid fuels. In this study, the feasibility of ethanol production from waste paper using the separate hydrolysis and fermentation (SHF) was investigated. Two types of waste paper materials, newspaper and office paper, were evaluated for their potential to be used as a renewable feedstock for the production of fermentable sugars via enzymatic hydrolysis of their cellulose fractions. Hydrolysis step was conducted with a mixture of cellulolytic enzymes produced locally by Trichoderma reesei Rut-C30 (cellulase-overproducing mutant) and Aspergillus niger F38 cultures. Surfactant pretreatment effect on waste paper enzymatic digestibility was studied and Triton X-100 at 0.5 % (w w(-1)) has improved the digestibility of newspaper about 45 %. The effects of three factors (dry matter quantity, phosphoric acid pretreatment and hydrolysis time) on the extent of saccharification were also assessed and quantified by using a methodical approach based on response surface methodology. Under optimal hydrolysis conditions, maximum degrees of saccharification of newspaper and office paper were 67 and 92 %, respectively. Sugars released from waste paper were subsequently converted into ethanol (0.38 g ethanol g(-1) sugar) with Saccharomyces cerevisiae CTM-30101.

  9. Real-time observation of the swelling and hydrolysis of a single crystalline cellulose fiber catalyzed by cellulase 7B from Trichoderma reesei.

    PubMed

    Wang, Jingpeng; Quirk, Amanda; Lipkowski, Jacek; Dutcher, John R; Hill, Christopher; Mark, Adam; Clarke, Anthony J

    2012-06-26

    The biodegradation of cellulose involves the enzymatic action of cellulases (endoglucanases), cellobiohydrolases (exoglucanases), and β-glucosidases that act synergistically. The rate and efficiency of enzymatic hydrolysis of crystalline cellulose in vitro decline markedly with time, limiting the large-scale, cost-effective production of cellulosic biofuels. Several factors have been suggested to contribute to this phenomenon, but there is considerable disagreement regarding the relative importance of each. These earlier investigations were hampered by the inability to observe the disruption of crystalline cellulose and its subsequent hydrolysis directly. Here, we show the application of high-resolution atomic force microscopy to observe the swelling of a single crystalline cellulose fiber and its-hydrolysis in real time directly as catalyzed by a single cellulase, the industrially important cellulase 7B from Trichoderma reesei. Volume changes, the root-mean-square roughness, and rates of hydrolysis of the surfaces of single fibers were determined directly from the images acquired over time. Hydrolysis dominated the early stage of the experiment, and swelling dominated the later stage. The high-resolution images revealed that the combined action of initial hydrolysis followed by swelling exposed individual microfibrils and bundles of microfibrils, resulting in the loosening of the fiber structure and the exposure of microfibrils at the fiber surface. Both the hydrolysis and swelling were catalyzed by the native cellulase; under the same conditions, its isolated carbohydrate-binding module did not cause changes to crystalline cellulose. We anticipate that the application of our AFM-based analysis on other cellulolytic enzymes, alone and in combination, will provide significant insight into the process of cellulose biodegradation and greatly facilitate its application for the efficient and economical production of cellulosic ethanol.

  10. Expression of Trichoderma reesei β-mannanase in tobacco chloroplasts and its utilization in lignocellulosic woody biomass hydrolysis.

    PubMed

    Agrawal, Pankaj; Verma, Dheeraj; Daniell, Henry

    2011-01-01

    Lignocellulosic ethanol offers a promising alternative to conventional fossil fuels. One among the major limitations in the lignocellulosic biomass hydrolysis is unavailability of efficient and environmentally biomass degrading technologies. Plant-based production of these enzymes on large scale offers a cost-effective solution. Cellulases, hemicellulases including mannanases and other accessory enzymes are required for conversion of lignocellulosic biomass into fermentable sugars. β-mannanase catalyzes endo-hydrolysis of the mannan backbone, a major constituent of woody biomass. In this study, the man1 gene encoding β-mannanase was isolated from Trichoderma reesei and expressed via the chloroplast genome. PCR and Southern hybridization analysis confirmed site-specific transgene integration into the tobacco chloroplast genomes and homoplasmy. Transplastomic plants were fertile and set viable seeds. Germination of seeds in the selection medium showed inheritance of transgenes into the progeny without any Mendelian segregation. Expression of endo-β-mannanase for the first time in plants facilitated its characterization for use in enhanced lignocellulosic biomass hydrolysis. Gel diffusion assay for endo-β-mannanase showed the zone of clearance confirming functionality of chloroplast-derived mannanase. Endo-β-mannanase expression levels reached up to 25 units per gram of leaf (fresh weight). Chloroplast-derived mannanase had higher temperature stability (40 °C to 70 °C) and wider pH optima (pH 3.0 to 7.0) than E.coli enzyme extracts. Plant crude extracts showed 6-7 fold higher enzyme activity than E.coli extracts due to the formation of disulfide bonds in chloroplasts, thereby facilitating their direct utilization in enzyme cocktails without any purification. Chloroplast-derived mannanase when added to the enzyme cocktail containing a combination of different plant-derived enzymes yielded 20% more glucose equivalents from pinewood than the cocktail without

  11. Pretreatment and enzymatic hydrolysis of corn fiber

    SciTech Connect

    Grohmann, K.; Bothast, R.J.

    1996-10-01

    Corn fiber is a co-product of the corn wet milling industry which is usually marketed as a low value animal feed ingredient. Approximately 1.2 x 10{sup 6} dry tons of this material are produced annually in the United States. The fiber is composed of kernel cell wall fractions and a residual starch which can all be potentially hydrolyzed to a mixture of glucose, xylose, arabinose and galactose. We have investigated a sequential saccharification of polysaccharides in corn fiber by a treatment with dilute sulfuric acid at 100 to 160{degrees}C followed by partial neutralization and enzymatic hydrolysis with mixed cellulose and amyloglucosidase enzymes at 45{degrees}C. The sequential treatment achieved a high (approximately 85%) conversion of all polysaccharides in the corn fiber to monomeric sugars, which were in most cases fermentable to ethanol by the recombinant bacterium Escherichia coli KOll.

  12. Adsorption and synergism of cellobiohydrolase I and II of Trichoderma reesei during hydrolysis of microcrystalline cellulose

    SciTech Connect

    Medve, J.; Tjerneld, F. . Dept. of Biochemistry); Staahlberg, J. . Dept. of Molecular Biology)

    1994-11-05

    Hydrolysis of microcrystalline cellulose (Avicel) by cellobiohydrolase I and II (CBH I and II) from Trichoderma reesei has been studied. Adsorption and synergism of the enzymes were investigated. Experiments were performed at different temperatures and enzyme/substrate ratios using CBH I and CBH II alone and in reconstituted equimolar mixtures. Fast protein liquid chromatography (FPLC) analysis was found to be an accurate and reproducible method to follow the enzyme adsorption. A linear correlation was found between the conversion and the amount of adsorbed enzyme when Avicel was hydrolyzed by increasing amounts of CBH I and/or CBH II. CBH I had lower specific activity compared to CBH II although, over a wide concentration range, more CBH I was adsorbed than CBH II. Synergism between the cellobiohydrolases during hydrolysis of the amorphous fraction of Avicel showed a maximum as a function of total enzyme concentration. Synergism measured as a function of bound enzyme showed a continuous increase, which indicates that by decreasing the distance between the two enzymes the synergism is enhanced. The adsorption process for both enzymes was slow. Depending on the enzyme/substrate ratio it took 30--90 min to reach 95% of the equilibrium binding. The amount of bound enzyme decreased with increasing temperature. The two enzymes compete for the adsorption sites but also bind to specific sites. Stronger competition for adsorption sites was shown by CBH I.

  13. Studies on the Enzymatic Hydrolysis of Organophosphate Poisons in Pigs.

    DTIC Science & Technology

    1982-11-01

    Idantlty by Woe« numb«-; Hydrolysis Of the OrganO- phosphate paraoxon was studied in Yorkshire pig, rat and human sera. Enzymatic hydrolysis ...D-A123 269 UNCLASSIFIED STUDIES ON THE ENZYMATIC HYDROLYSIS OF ORGflNOPHOSPHATE 1/i POISONS IN PIGS(U) LETTERNAN ARMY INST OF RESEARCH...ON THE ENZYMATIC HYDROLYSIS OF ORGANOPHOSPHATE POISONS IN PIGS Part 1. pH and Ion Effects in Sera from Pigs, Rats, and Humans PETER SCHMID, PhD

  14. Cellulose hydrolysis and binding with Trichoderma reesei Cel5A and Cel7A and their core domains in ionic liquid solutions.

    PubMed

    Wahlström, Ronny; Rahikainen, Jenni; Kruus, Kristiina; Suurnäkki, Anna

    2014-04-01

    Ionic liquids (ILs) dissolve lignocellulosic biomass and have a high potential as pretreatment prior to total enzymatic hydrolysis. ILs are, however, known to inactivate cellulases. In this article, enzymatic hydrolysis of microcrystalline cellulose (MCC) and enzyme binding onto the cellulosic substrate were studied in the presence of cellulose-dissolving ILs. Two different ILs, 1,3-dimethylimidazolium dimethylphosphate ([DMIM]DMP) and 1-ethyl-3-methylimidazolium acetate ([EMIM]AcO), and two monocomponent cellulases, Trichoderma reesei cellobiohydrolase Cel7A and endoglucanase Cel5A, were used in the study. The role and IL sensitivity of the carbohydrate-binding module (CBM) were studied by performing hydrolysis and binding experiments with both the intact cellulases, and their respective core domains (CDs). Based on hydrolysis yields and substrate binding experiments for the intact enzymes and their CDs in the presence of ILs, the function of the CBM appeared to be very IL sensitive. Binding data suggested that the CBM was more important for the substrate binding of endoglucanase Cel5A than for the binding of cellobiohydrolase Cel7A. The CD of Cel7A was able to bind well to cellulose even without a CBM, whereas Cel5A CD had very low binding affinity. Hydrolysis also occurred with Cel5A CD even if this protein had very low binding affinity in all the studied matrices. Binding and hydrolysis were less affected by the studied ILs for Cel7A than for Cel5A. To our knowledge, this is the first systematic study of IL effects on cellulase substrate binding.

  15. Enzymatic Hydrolysis of Hydrotropic Pulps at Different Substrate Loadings.

    PubMed

    Denisova, Marina N; Makarova, Ekaterina I; Pavlov, Igor N; Budaeva, Vera V; Sakovich, Gennady V

    2016-03-01

    Enzymatic hydrolysis of cellulosic raw materials to produce nutrient broths for microbiological synthesis of ethanol and other valuable products is an important field of modern biotechnology. Biotechnological processing implies the selection of an effective pretreatment technique for raw materials. In this study, the hydrotropic treatment increased the reactivity of the obtained substrates toward enzymatic hydrolysis by 7.1 times for Miscanthus and by 7.3 times for oat hulls. The hydrotropic pulp from oat hulls was more reactive toward enzymatic hydrolysis compared to that from Miscanthus, despite that the substrates had similar compositions. As the initial substrate loadings were raised during enzymatic hydrolysis of the hydrotropic Miscanthus and oat hull pulps, the concentration of reducing sugars increased by 34 g/dm(3) and the yield of reducing sugars decreased by 31 %. The findings allow us to predict the efficiency of enzymatic hydrolysis of hydrotropic pulps from Miscanthus and oat hulls when scaling up the process by volume.

  16. Evaluation of Enzymatic Hydrolysis of CELSS Wheat Residue Cellulose at a Scale Environment to NASA's KSC Breadboard Project

    NASA Technical Reports Server (NTRS)

    Strayer, Richard F.

    1993-01-01

    Biomass processing at the Kennedy Space Center CELSS breadboard project has focused on the evaluation of breadboard-scale enzymatic hydrolysis of wheat residue cellulose (25%, w/w). Five replicate runs of cellulase production by Trichoderma reesei (QM9414) and enzymatic hydrolysis of residue cellulose were completed. Enzymes were produced in 1 0 days (5 L, 25 g (dry weight) residue). Cellulose hydrolysis (12 L, 50 g (dry weight) residue) using these enzymes produced 5.5 to 6.0 g glucose liter(exp -1) in 7 days. Cellulose conversion efficiency was 29%. These processes are feasible technically on a breadboard scale, but would only increase the edible wheat yield 10%.

  17. Evaluation of Enzymatic Hydrolysis of CELSS Wheat Residue Cellulose at a Scale Environment to NASA's KSC Breadboard Project

    NASA Technical Reports Server (NTRS)

    Strayer, Richard F.

    1993-01-01

    Biomass processing at the Kennedy Space Center CELSS breadboard project has focused on the evaluation of breadboard-scale enzymatic hydrolysis of wheat residue cellulose (25%, w/w). Five replicate runs of cellulase production by Trichoderma reesei (QM9414) and enzymatic hydrolysis of residue cellulose were completed. Enzymes were produced in 1 0 days (5 L, 25 g (dry weight) residue). Cellulose hydrolysis (12 L, 50 g (dry weight) residue) using these enzymes produced 5.5 to 6.0 g glucose liter(exp -1) in 7 days. Cellulose conversion efficiency was 29%. These processes are feasible technically on a breadboard scale, but would only increase the edible wheat yield 10%.

  18. Short-time ultrasonication treatment in enzymatic hydrolysis of biomass

    Treesearch

    Zengqian Shi; Zhiyong Cai; Siqun Wang; Qixin Zhong; Joseph J. Bozell

    2013-01-01

    To improve the conversion of enzymatic hydrolysis of biomass in an energy-efficient manner, two shorttime ultrasonication strategies were applied on six types of biomass with different structures and components. The strategies include pre-sonication before the hydrolysis and intermittent sonication during the ongoing hydrolysis. The microstructures of each type of...

  19. A kinetic study of Trichoderma reesei Cel7B catalyzed cellulose hydrolysis.

    PubMed

    Song, Xiangfei; Zhang, Shujun; Wang, Yefei; Li, Jingwen; He, Chunyan; Yao, Lishan

    2016-06-01

    One prominent feature of Trichoderma reesei (Tr) endoglucanases catalyzed cellulose hydrolysis is that the reaction slows down quickly after it starts (within minutes). But the mechanism of the slowdown is not well understood. A structural model of Tr- Cel7B catalytic domain bound to cellulose was built computationally and the potentially important binding residues were identified and tested experimentally. The 13 tested mutants show different binding properties in the adsorption to phosphoric acid swollen cellulose and filter paper. Though the partitioning parameter to filter paper is about 10 times smaller than that to phosphoric acid swollen cellulose, a positive correlation is shown for two substrates. The kinetic studies show that the reactions slow down quickly for both substrates. This slowdown is not correlated to the binding constant but anticorrelated to the enzyme initial activity. The amount of reducing sugars released after 24h by Cel7B in phosphoric acid swollen cellulose, Avicel and filter paper cellulose hydrolysis is correlated with the enzyme activity against a soluble substrate p-nitrophenyl lactoside. Six of the 13 tested mutants, including N47A, N52D, S99A, N323D, S324A, and S346A, yield ∼15-35% more reducing sugars than the wild type (WT) Cel7B in phosphoric acid swollen cellulose and filter paper hydrolysis. This study reveals that the slowdown of the reaction is not due to the binding of the enzyme to cellulose. The activity of Tr- Cel7B against the insoluble substrate cellulose is determined by the enzyme's capability in hydrolyzing the soluble substrate.

  20. Effect of Ultrasonic Frequency on Enzymatic Hydrolysis of Cellulose

    NASA Astrophysics Data System (ADS)

    Yasuda, Keiji; Kato, Daiki; Xu, Zheng; Sakka, Makiko; Sakka, Kazuo

    2010-07-01

    The effect of ultrasonic frequency on the enzymatic hydrolysis of cellulose was examined. As the cellulose and enzyme, needle unbleached kraft pulp and cellulase were used. In the cases of the horn-type transducer at 20 kHz and the plate-type transducer at 28 kHz, the enzymatic hydrolysis was accelerated by ultrasonic irradiation. Total sugar concentration linearly increased with ultrasonic intensity. On the other hand, in the case of the plate-type transducer at 500 kHz, the enzymatic hydrolysis was inhibited. Total sugar concentration decreased with increasing ultrasonic intensity.

  1. Enzymatic hydrolysis of biomass from wood.

    PubMed

    Álvarez, Consolación; Reyes-Sosa, Francisco Manuel; Díez, Bruno

    2016-03-01

    Current research and development in cellulosic ethanol production has been focused mainly on agricultural residues and dedicated energy crops such as corn stover and switchgrass; however, woody biomass remains a very important feedstock for ethanol production. The precise composition of hemicellulose in the wood is strongly dependent on the plant species, therefore different types of enzymes are needed based on hemicellulose complexity and type of pretreatment. In general, hardwood species have much lower recalcitrance to enzymes than softwood. For hardwood, xylanases, beta-xylosidases and xyloglucanases are the main hemicellulases involved in degradation of the hemicellulose backbone, while for softwood the effect of mannanases and beta-mannosidases is more relevant. Furthermore, there are different key accessory enzymes involved in removing the hemicellulosic fraction and increasing accessibility of cellulases to the cellulose fibres improving the hydrolysis process. A diversity of enzymatic cocktails has been tested using from low to high densities of biomass (2-20% total solids) and a broad range of results has been obtained. The performance of recently developed commercial cocktails on hardwoods and softwoods will enable a further step for the commercialization of fuel ethanol from wood.

  2. Comparison of different pretreatment strategies for enzymatic hydrolysis of wheat and barley straw.

    PubMed

    Rosgaard, Lisa; Pedersen, Sven; Meyer, Anne S

    2007-12-01

    In biomass-to-ethanol processes a physico-chemical pretreatment of the lignocellulosic biomass is a critical requirement for enhancing the accessibility of the cellulose substrate to enzymatic attack. This report evaluates the efficacy on barley and wheat straw of three different pretreatment procedures: acid or water impregnation followed by steam explosion versus hot water extraction. The pretreatments were compared after enzyme treatment using a cellulase enzyme system, Celluclast 1.5 L from Trichoderma reesei, and a beta-glucosidase, Novozyme 188 from Aspergillus niger. Barley straw generally produced higher glucose concentrations after enzymatic hydrolysis than wheat straw. Acid or water impregnation followed by steam explosion of barley straw was the best pretreatment in terms of resulting glucose concentration in the liquid hydrolysate after enzymatic hydrolysis. When the glucose concentrations obtained after enzymatic hydrolyses were related to the potential glucose present in the pretreated residues, the highest yield, approximately 48% (g g-1), was obtained with hot water extraction pretreatment of barley straw; this pretreatment also produced highest yields for wheat straw, producing a glucose yield of approximately 39% (g g-1). Addition of extra enzyme (Celluclast 1.5 L+Novozyme 188) during enzymatic hydrolysis resulted in the highest total glucose concentrations from barley straw, 32-39 g L-1, but the relative increases in glucose yields were higher on wheat straw than on barley straw. Maldi-TOF MS analyses of supernatants of pretreated barley and wheat straw samples subjected to acid and water impregnation, respectively, and steam explosion, revealed that the water impregnated + steam-exploded samples gave a wider range of pentose oligomers than the corresponding acid-impregnated samples.

  3. Effect of pretreatment and enzymatic hydrolysis of wheat straw on cell wall composition, hydrophobicity and cellulase adsorption.

    PubMed

    Heiss-Blanquet, Senta; Zheng, Dan; Lopes Ferreira, Nicolas; Lapierre, Catherine; Baumberger, Stéphanie

    2011-05-01

    The present study aimed to determine the impact of cell wall composition and lignin content on enzyme adsorption and degradability. Thioacidolysis analysis of residual lignins in wheat straw after steam-explosion or organosolv pretreatment revealed an increase in lignin condensation degree of 27% and 33%, respectively. Surface hydrophobicity assessed through wettability tests decreased after the pretreatments (contact angle decrease of 20-50%), but increased with enzymatic conversion (30% maximum contact angle increase) and correlatively to lignin content. Adsorption of the three major cellulases Cel7A, Cel6A and Cel7B from Trichoderma reesei decreased with increasing hydrolysis time, down to 7%, 31% and 70% on the sample with the highest lignin content, respectively. The fraction of unspecifically bound enzymes was dependent both on the enzyme and the lignin content. Adsorption and specific activity were shown to be inversely proportional to lignin content and hydrophobicity, suggesting that lignin is one of the factors restricting enzymatic hydrolysis.

  4. Enzymatic hydrolysis of microcrystalline cellulose and pretreated wheat straw: a detailed comparison using convenient kinetic analysis.

    PubMed

    Monschein, Mareike; Reisinger, Christoph; Nidetzky, Bernd

    2013-01-01

    Marked slow-down of soluble sugar production at low degree of substrate conversion limits the space-time yield of enzymatic hydrolysis of ligno-cellulosic materials. A simple set of kinetic descriptors was developed to compare reducing sugar release from pure crystalline cellulose (Avicel) and pretreated wheat straw by Trichoderma reesei cellulase at 50 °C. The focus was on the rate-retarding effect of maximum hydrolysis rate at reaction start (r(max)), limiting hydrolysis rate (r(lim)) at extended reaction time (24h), and substrate conversion, marking the transition between the r(max) and r(lim) kinetic regimes (C(trans)). At apparent saturation of substrate (12.2g cellulose/L) with enzyme, r(max) for pretreated wheat straw (~9.6g/L/h) surpassed that for Avicel by about 1.7-fold whereas their r(lim) were almost identical (~0.15 g/L/h). C(trans) roughly doubled as enzyme/substrate loading was increased from 3.8 to 75FPU/g, suggesting C(trans) to be a complex manifestation of cellulase-cellulose interaction, not an intrinsic substrate property. A low-temperature adsorption step preceding hydrolysis at 50 °C resulted in enhanced cellulase binding at reaction start without increasing r(max). C(trans) was higher for pretreated wheat straw (~30%) than for Avicel (~20%) under these conditions.

  5. Ultrasound enhanced enzymatic hydrolysis of Parthenium hysterophorus: A mechanistic investigation.

    PubMed

    Singh, Shuchi; Agarwal, Mayank; Bhatt, Aditya; Goyal, Arun; Moholkar, Vijayanand S

    2015-09-01

    This study has attempted to establish the mechanism of the ultrasound-induced enhancement of enzymatic hydrolysis of pretreated and delignified biomass of Parthenium hysterophorus. A dual approach of statistical optimization of hydrolysis followed by application of sonication at optimum conditions has been adopted. The kinetics of hydrolysis shows a marked 6× increase with sonication, while net sugar yield shows marginal rise of ∼ 20%. The statistical experimental design reveals the hydrolysis process to be enzyme limited. Profile of sugar yield in ultrasound-assisted enzymatic hydrolysis has been analyzed using HCH-1 model coupled with Genetic Algorithm optimization. The trends in the kinetic and physiological parameters of HCH-1 model reveal that sonication enhances enzyme/substrate affinity and reaction velocity of hydrolysis. The product inhibition of enzyme in all forms (free, adsorbed, complexed) also reduces with ultrasound. These effects are attributed to intense micro-convection induced by ultrasound and cavitation in the liquid medium.

  6. Ultrasound Enhancement of Enzymatic Hydrolysis of Cellulose Plant Matter

    USDA-ARS?s Scientific Manuscript database

    The work reported here is based on acceleration of enzymatic hydrolysis of plant biomass substrate by introduction of low intensity, uniform ultrasound field into a reaction chamber (bio-reactor). This method may serve as improvement of rates in the hydrolysis of cellulosic materials to sugars, whi...

  7. Enzymatic hydrolysis of steryl ferulates and steryl glycosides

    USDA-ARS?s Scientific Manuscript database

    Steryl ferulates and steryl glycosides are phytosterol conjugates found characteristically in cereals. Their properties in enzymatic hydrolysis are, however, not yet well known. Steryl ferulates and steryl glycosides were extracted and purified from rye and wheat bran. Their rates of hydrolysis with...

  8. Synergies in coupled hydrolysis and fermentation of cellulose using a Trichoderma reesei enzyme preparation and a recombinant Saccharomyces cerevisiae strain.

    PubMed

    Casa-Villegas, Mary; Marín-Navarro, Julia; Polaina, Julio

    2017-07-01

    We describe a procedure by which filter paper is digested with a cellulolytic enzyme preparation, obtained from Trichoderma reesei cultivated under solid state fermentation conditions and then fermented by a recombinant Saccharomyces cerevisiae strain. The yeast strain produces a β-glucosidase encoded by the BGL1 gene from Saccharomycopsis fibuligera that quantitatively and qualitatively complements the limitations that the Trichoderma enzyme complex shows for this particular activity. The supplemental β-glucosidase activity fuels the progression of cellulose hydrolysis and fermentation by decreasing the inhibitory effects caused by the accumulation of cellobiose and glucose. Fermentation of filter paper by this procedure yields ethanol concentrations above 70 g/L.

  9. The role of acetyl xylan esterase in the solubilization of xylan and enzymatic hydrolysis of wheat straw and giant reed

    PubMed Central

    2011-01-01

    Background Due to the complexity of lignocellulosic materials, a complete enzymatic hydrolysis into fermentable sugars requires a variety of cellulolytic and xylanolytic enzymes. Addition of xylanases has been shown to significantly improve the performance of cellulases and to increase cellulose hydrolysis by solubilizing xylans in lignocellulosic materials. The goal of this work was to investigate the effect of acetyl xylan esterase (AXE) originating from Trichoderma reesei on xylan solubilization and enzymatic hydrolysis of cellulose. Results The solubilization of xylan in pretreated wheat straw and giant reed (Arundo donax) by xylanolytic enzymes and the impact of the sequential or simultaneous solubilization of xylan on the hydrolysis of cellulose by purified enzymes were investigated. The results showed that the removal of acetyl groups in xylan by AXE increased the accessibility of xylan to xylanase and improved the hydrolysis of xylan in pretreated wheat straw and giant reed. Solubilization of xylan led to an increased accessibility of cellulose to cellulases and thereby increased the hydrolysis extent of cellulose. A clear synergistic effect between cellulases and xylanolytic enzymes was observed. The highest hydrolysis yield of cellulose was obtained with a simultaneous use of cellulases, xylanase and AXE, indicating the presence of acetylated xylan within the cellulose matrix. Acetylated xylobiose and acetylated xylotriose were produced from xylan without AXE, as confirmed by atmospheric pressure matrix-assisted laser desorption/ionization ion trap mass spectrometry. Conclusions The results in this paper demonstrate that supplementation of xylanase with AXE enhances the solubilization of xylan to some extent and, consequently, increases the subsequent hydrolysis of cellulose. The highest hydrolysis yield was, however, obtained by simultaneous hydrolysis of xylan and cellulose, indicating a layered structure of cellulose and xylan chains in the cell wall

  10. Ultrasound mediated enzymatic hydrolysis of cellulose and carboxymethyl cellulose.

    PubMed

    Sulaiman, Ahmad Ziad; Ajit, Azilah; Chisti, Yusuf

    2013-01-01

    A recombinant Trichoderma reesei cellulase was used for the ultrasound-mediated hydrolysis of soluble carboxymethyl cellulose (CMC) and insoluble cellulose of various particle sizes. The hydrolysis was carried out at low intensity sonication (2.4-11.8 W cm(-2) sonication power at the tip of the sonotrode) using 10, 20, and 40% duty cycles. [A duty cycle of 10%, for example, was obtained by sonicating for 1 s followed by a rest period (no sonication) of 9 s.] The reaction pH and temperature were always 4.8 and 50°C, respectively. In all cases, sonication enhanced the rate of hydrolysis relative to nonsonicated controls. The hydrolysis of CMC was characterized by Michaelis-Menten kinetics. The Michaelis-Menten parameter of the maximum reaction rate Vmax was enhanced by sonication relative to controls, but the value of the saturation constant Km was reduced. The optimal sonication conditions were found to be a 10% duty cycle and a power intensity of 11.8 W cm(-2) . Under these conditions, the maximum rate of hydrolysis of soluble CMC was nearly double relative to control. In the hydrolysis of cellulose, an increasing particle size reduced the rate of hydrolysis. At any fixed particle size, sonication at a 10% duty cycle and 11.8 W cm(-2) power intensity improved the rate of hydrolysis relative to control. Under the above mentioned optimal sonication conditions, the enzyme lost about 20% of its initial activity in 20 min. Sonication was useful in accelerating the enzyme catalyzed saccharification of cellulose.

  11. Enzymatic hydrolysis and characterization of lignocellulosic biomass exposed to electron beam irradiation.

    PubMed

    Karthika, K; Arun, A B; Rekha, P D

    2012-10-01

    Pretreatment of lignocellulosic biomass has been taken up as a global challenge as it comprises a large renewable source of fermentable sugars. In this study, effect of electron beam irradiation (EBI) on a hybrid grass variety investigated as a biomass pretreatment method. Dry biomass samples after characterization were exposed to EBI doses of 0, 75, 150 and 250 kGy. The pretreated biomass samples were enzymatically hydrolyzed using Trichoderma reesei ATCC 26921 cellulase for 144 h. The enzyme loadings were 15 and 30 FPU/g of biomass. The structural changes and degree of crystallinity of the pretreated biomass were studied by FTIR, XRD and SEM analyses. The lignocellulosic biomass sample showed 12.0% extractives, 36.9% cellulose, 28.4% hemicellulose, 11.9% lignin and 8.6% ash. Significant improvements in the reducing sugar and glucose yields were observed in the hydrolysate of EBI pretreated biomass compared to the control. In 250 kGy exposed samples 79% of the final reducing sugar yield was released within 48 h of hydrolysis at an enzyme loading rate of 30FPU/g of biomass. The IR crystallinity index calculated from the FTIR data and degree of crystallinity (XRD) decreased in the EBI treated samples. A significant negative correlation was observed between degree of crystallinity and the glucose yield from enzymatic hydrolysis.

  12. Sugarcane bagasse enzymatic hydrolysis: rheological data as criteria for impeller selection.

    PubMed

    Pereira, Leonardo Tupi Caldas; Pereira, Lucas Tupi Caldas; Teixeira, Ricardo Sposina Sobral; Bon, Elba Pinto da Silva; Freitas, Suely Pereira

    2011-08-01

    The aim of this work was to select an efficient impeller to be used in a stirred reactor for the enzymatic hydrolysis of sugar cane bagasse. All experiments utilized 100 g (dry weight)/l of steam-pretreated bagasse, which is utilized in Brazil for cattle feed. The process was studied with respect to the rheological behavior of the biomass hydrolysate and the enzymatic conversion of the bagasse polysaccharides. These parameters were applied to model the power required for an impeller to operate at pilot scale (100 l) using empirical correlations according to Nagata [16]. Hydrolysis experiments were carried out using a blend of cellulases, β-glucosidase, and xylanases produced in our laboratory by Trichoderma reesei RUT C30 and Aspergillus awamori. Hydrolyses were performed with an enzyme load of 10 FPU/g (dry weight) of bagasse over 36 h with periodic sampling for the measurement of viscosity and the concentration of glucose and reducing sugars. The mixture presented pseudoplastic behavior. This rheological model allowed for a performance comparison to be made between flat-blade disk (Rushton turbine) and pitched-blade (45°) impellers. The simulation showed that the pitched blade consumed tenfold less energy than the flat-blade disk turbine. The resulting sugar syrups contained 22 g/l of glucose, which corresponded to 45% cellulose conversion.

  13. Transition-state structures for enzymatic and alkaline phosphotriester hydrolysis

    SciTech Connect

    Caldwell, S.R.; Raushel, F.M. ); Weiss, P.M.; Cleland, W.W. )

    1991-07-30

    The primary and secondary {sup 18}O isotope effects for the alkaline (KOH) and enzymatic (phosphotriesterase) hydrolysis of two phosphotriesters, O,O-diethyl p-nitrophenyl phosphate (I) and O,O-diethyl O-(4-carbamoylphenyl) phosphate (II), are consistent with an associative mechanism with significant changes in bond order to both the phosphoryl and phenolic leaving group oxygens in the transition state. The synthesis of ({sup 15}N, phosphoryl-{sup 18}O)-,({sup 15}N, phenolic-{sup 18}O)-, and ({sup 15}N)-O,O-diethyl p-nitrophenyl phosphate and O,O-diethyl O-(4-carbamoylphenyl)phosphate is described. The primary and secondary {sup 18}O isotope effects for the alkaline hydrolysis of compound I are 1.0060 and 1.0063 {plus minus} 0.0001, whereas for compound II they are 1.027{plus minus}0.002 and 1.025 {plus minus} 0.002, respectively. These isotope effects are consistent with the rate-limiting addition of hydroxide and provide evidence for a S{sub N}2-like transition state with the absence of a stable phosphorane intermediate. For the enzymatic hydrolysis of compound I, the primary and secondary {sup 18}O isotope effects are very small, 1.0020 and 1.0021{plus minus}0.0004, respectively, and indicate that the chemical step in the enzymatic mechanism is not rate-limiting. The {sup 18}O isotope effects for the enzymatic hydrolysis of compound II are 1.036{plus minus}0.001 and 1.0181{plus minus}0.0007, respectively, and are comparable in magnitude to the isotope effects for alkaline hydrolysis, suggesting that the chemical step is rate-limiting. The relative magnitude of the primary {sup 18}O isotope effects for the alkaline and enzymatic hydrolysis of compound II reflect a transition state that is more progressed for the enzymatic reaction.

  14. Transition-state structures for enzymatic and alkaline phosphotriester hydrolysis.

    PubMed

    Caldwell, S R; Raushel, F M; Weiss, P M; Cleland, W W

    1991-07-30

    The primary and secondary 18O isotope effects for the alkaline (KOH) and enzymatic (phosphotriesterase) hydrolysis of two phosphotriesters, O,O-diethyl p-nitrophenyl phosphate (I) and O,O-diethyl O-(4-carbamoylphenyl) phosphate (II), are consistent with an associative mechanism with significant changes in bond order to both the phosphoryl and phenolic leaving group oxygens in the transition state. The synthesis of [15N, phosphoryl-18O]-, [15N, phenolic-18O]-, and [15N]-O,O-diethyl p-nitrophenyl phosphate and O,O-diethyl O-(4-carbamoylphenyl)phosphate is described. The primary and secondary 18O isotope effects for the alkaline hydrolysis of compound I are 1.0060 and 1.0063 +/- 0.0001, whereas for compound II they are 1.027 +/- 0.002 and 1.025 +/- 0.002, respectively. These isotope effects are consistent with the rate-limiting addition of hydroxide and provide evidence for a SN2-like transition state with the absence of a stable phosphorane intermediate. For the enzymatic hydrolysis of compound I, the primary and secondary 18O isotope effects are very small, 1.0020 and 1.0021 +/- 0.0004, respectively, and indicate that the chemical step in the enzymatic mechanism is not rate-limiting. The 18O isotope effects for the enzymatic hydrolysis of compound II are 1.036 +/- 0.001 and 1.0181 +/- 0.0007, respectively, and are comparable in magnitude to the isotope effects for alkaline hydrolysis, suggesting that the chemical step is rate-limiting. The relative magnitude of the primary 18O isotope effects for the alkaline and enzymatic hydrolysis of compound II reflect a transition state that is more progressed for the enzymatic reaction.

  15. Effect of pretreatment severity in continuous steam explosion on enzymatic conversion of wheat straw: Evidence from kinetic analysis of hydrolysis time courses.

    PubMed

    Monschein, Mareike; Nidetzky, Bernd

    2016-01-01

    Focusing on continuous steam explosion, the influence of pretreatment severity due to varied acid loading on hydrolysis of wheat straw by Trichoderma reesei cellulases was investigated based on kinetic evaluation of the saccharification of each pretreated substrate. Using semi-empirical descriptors of the hydrolysis time course, key characteristics of saccharification efficiency were captured in a quantifiable fashion. Not only hydrolysis rates per se, but also the transition point of their bi-phasic decline was crucial for high saccharification degree. After 48h the highest saccharification was achieved for substrate pretreated at relatively low severity (1.2% acid). Higher severity increased enzyme binding to wheat straw, but reduced the specific hydrolysis rates. Higher affinity of the lignocellulosic material for cellulases does not necessarily result in increased saccharification, probably because of lignin modifications occurring at high pretreatment severities. At comparable severity, continuous pretreatment produced a substrate more susceptible to enzymatic hydrolysis than the batch process.

  16. Functional characterization of the native swollenin from Trichoderma reesei: study of its possible role as C1 factor of enzymatic lignocellulose conversion.

    PubMed

    Eibinger, Manuel; Sigl, Karin; Sattelkow, Jürgen; Ganner, Thomas; Ramoni, Jonas; Seiboth, Bernhard; Plank, Harald; Nidetzky, Bernd

    2016-01-01

    Through binding to cellulose, expansin-like proteins are thought to loosen the structural order of crystalline surface material, thus making it more accessible for degradation by hydrolytic enzymes. Swollenin SWO1 is the major expansin-like protein from the fungus Trichoderma reesei. Here, we have performed a detailed characterization of a recombinant native form of SWO1 with respect to its possible auxiliary role in the enzymatic saccharification of lignocellulosic substrates. The swo1 gene was overexpressed in T. reesei QM9414 Δxyr1 mutant, featuring downregulated cellulase production, and the protein was purified from culture supernatant. SWO1 was N-glycosylated and its circular dichroism spectrum suggested a folded protein. Adsorption isotherms (25 °C, pH 5.0, 1.0 mg substrate/mL) revealed SWO1 to be 120- and 20-fold more specific for binding to birchwood xylan and kraft lignin, respectively, than for binding to Avicel PH-101. The SWO1 binding capacity on lignin (25 µmol/g) exceeded 12-fold that on Avicel PH-101 (2.1 µmol/g). On xylan, not only the binding capacity (22 µmol/g) but also the affinity of SWO1 (K d = 0.08 µM) was enhanced compared to Avicel PH-101 (K d = 0.89 µM). SWO1 caused rapid release of a tiny amount of reducing sugars (<1 % of total) from different substrates (Avicel PH-101, nanocrystalline cellulose, steam-pretreated wheat straw, barley β-glucan, cellotetraose) but did not promote continued saccharification. Atomic force microscopy revealed that amorphous cellulose films were not affected by SWO1. Also with AFM, binding of SWO1 to cellulose nanocrystallites was demonstrated at the single-molecule level, but adsorption did not affect this cellulose. SWO1 exhibited no synergy with T. reesei cellulases in the hydrolysis of the different celluloses. However, SWO1 boosted slightly (1.5-fold) the reducing sugar release from a native grass substrate. SWO1 is a strongly glycosylated protein, which has implications for producing

  17. Enzymatic hydrolysis of waste sugarcane bagasse in water media.

    PubMed

    Zheng, C; Lei, Y; Yu, Q; Lui, X; Huan, K

    2002-09-01

    Enzymatic hydrolysis of natural cellulose such as sugarcane bagasse is usually carried out in a buffer medium. In this paper, the enzymatic hydrolysis of a waste sugarcane bagasse in water media was carried out.The bagasse was pre-treated with heating explosion and pure (ion exchange), reverse-osmosis and tap water media were used in place of a buffer solution in the hydrolysis process. The yields for reducing sugars and the changes in solution pH and electric conductivity during the hydrolysis under various conditions were studied. The results were also compared with those obtained in buffer solutions. Similar levels of sugar yields were obtained in water and buffer solution media. The pH of the hydrolyzate was in the range of 4.5 - 5.0, which coincided with the optimum pH for the enzyme reaction. It was considered that the enzyme and the substrate formed a transitional complex in the hydrolysis process. The transitional complex provided the buffering capacity pH 5. The results indicate of the hydrolyzate solution at around that industrialization of the enzymatic hydrolysis in a water medium is feasible.

  18. Epidemic based modeling of enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Tai, Chao; Arellano, Maria G; Keshwani, Deepak R

    2014-01-01

    An epidemic based model was developed to describe the enzymatic hydrolysis of a lignocellulosic biomass, dilute sulfuric acid pretreated corn stover. The process of substrate getting adsorbed and digested by enzyme was simulated as susceptibles getting infected by viruses and becoming removed and recovered. This model simplified the dynamic enzyme "infection" process and the catalysis of cellulose into a two-parameter controlled, enzyme behavior guided mechanism. Furthermore, the model incorporates the adsorption block by lignin and inhibition effects on cellulose catalysis. The model satisfactorily predicted the enzyme adsorption and hydrolysis, negative role of lignin, and inhibition effects over hydrolysis for a broad range of substrate and enzyme loadings. Sensitivity analysis was performed to evaluate the incorporation of lignin and other inhibition effects. Our model will be a useful tool for evaluating the effects of parameters during hydrolysis and guide a design strategy for continuous hydrolysis and the associated process control.

  19. Effect of pore size distribution on the rate of enzymatic hydrolysis of cellulosic substrates

    SciTech Connect

    Grethlein, H.E.

    1985-02-01

    Hard and softwoods were pretreated by mild acid hydrolysis and their pore size distribution determined. Regardless of the substrate, the initial rate of hydrolysis using cellulase from Trichoderma reesei is linearly correlated with the pore volume of the substrate accessible to a nominal diameter of 51 Angstroms representative of the size of the cellulase. In contrast, crystallinity index has no relationship to the rate of hydrolysis. 21 references.

  20. The Preparation and Enzymatic Hydrolysis of a Library of Esters

    ERIC Educational Resources Information Center

    Sanford, Elizabeth M.; Smith, Traci L.

    2008-01-01

    An investigative case study involving the preparation of a library of esters using Fischer esterification and alcoholysis of acid chlorides and their subsequent enzymatic hydrolysis by pig liver esterase and orange peel esterase is described. Students work collaboratively to prepare and characterize the library of esters and complete and evaluate…

  1. Kinetic Modeling of Enzymatic Hydrolysis of Pretreated Creeping Wild Ryegrass

    USDA-ARS?s Scientific Manuscript database

    A semimechanistic multi-reaction kinetic model was developed to describe the enzymatic hydrolysis of a lignocellulosic biomass, creeping wild ryegrass (CWR; Leymus triticoides). This model incorporated one homogeneous reaction of cellobiose-to-glucose and two heterogeneous reactions of cellulose-to...

  2. Effect of particle size on enzymatic hydrolysis of pretreated Miscanthus

    USDA-ARS?s Scientific Manuscript database

    Particle size reduction is a crucial factor in transportation logistics as well as cellulosic conversion. The effect of particle size on enzymatic hydrolysis of pretreated Miscanthus x giganteus was determined. Miscanthus was ground using a hammer mill equipped with screens having 0.08, 2.0 or 6.0...

  3. The Preparation and Enzymatic Hydrolysis of a Library of Esters

    ERIC Educational Resources Information Center

    Sanford, Elizabeth M.; Smith, Traci L.

    2008-01-01

    An investigative case study involving the preparation of a library of esters using Fischer esterification and alcoholysis of acid chlorides and their subsequent enzymatic hydrolysis by pig liver esterase and orange peel esterase is described. Students work collaboratively to prepare and characterize the library of esters and complete and evaluate…

  4. Enzymatic hydrolysis of fractionated products from oil thermally oxidated

    SciTech Connect

    Yashida, H.; Alexander, J.C.

    1983-01-01

    Enzymatic hydrolysis of the acylglycerol products obtained from thermally oxidized vegetable oils was studied. Corn, sunflower and soybean oils were heated in the laboratory at 180/sup 0/C for 50, 70 and 100 hr with aeration and directly fractionated by silicic acid column chromatography. By successive elution with 20%, then 60% isopropyl ether in n-hexane, and diethyl ether, the thermally oxidized oils were separated into three fractions: the nonpolar fraction (monomeric compounds), slightly polar fraction (dimeric compounds), and polar fraction comprising oligomeric compounds. Enzymatic hydrolysis with pancreatic lipase showed that the monomers were hydrolyzed as rapidly as the corresponding unheated oils, the dimers much more slowly, and the oligomeric compounds barely at all. Overall, the hydrolysis of the dimers was less than 23% of that for the monomers, with small differences among the oils. Longer heating periods resulted in greater reductions in hydrolysis of the dimeric compounds. These results suggest that the degree of enzymatic hydrolysis of the fractionated acylglycerol compounds is related to differences in the thermal oxidative deterioration, and amounts of polar compounds in the products. (33 Refs.)

  5. Enzymatic Hydrolysis of Cellulosic Wastes to Glucose

    DTIC Science & Technology

    1975-09-08

    ton ’of waste paper ,Weccan "’produce 1/2 ton oFgluco~ .which canb~ fermented to produce 69 gallbns ’dfethanol. . ". . . Conversion of cellulose...important effect C1 has on the hydrolysis reaction is shown in Figure 6. Using filter paper as the substrate and enzyme solutions with equal Cx activity...4 . ow 200, A BALL MILLED PULP PREPARED FROM SW40, 200 MESH, SROWN CO., BERLIN, N. H. . . ~ • WHATMAN NO.1 fILTER PAPER 13 • AVICEL

  6. Enzymatic hydrolysis of oligomeric models of poly-3-hydroxybutyrate.

    PubMed

    Scherer, T M; Fuller, R C; Goodwin, S; Lenz, R W

    2000-01-01

    The mechanism of the enzymatic degradation of poly([R]-3-hydroxybutyrate) (PHB) was investigated by using well-defined model substrates, including both linear and cyclic [R]-3-hydroxybutyrate (3HB) and [R]-3-hydroxyvalerate (3HV) oligomers, with two different PHB depolymerases. The linear and cyclic oligomers containing from 2 to 10 repeating units were hydrolyzed in solutions of the depolymerase isolated from Aspergillus fumigatus and Alcaligenes faecalis, and the rates of hydrolysis and types of products formed were characterized. Both of the depolymerases catalyzed the hydrolysis of the cyclic oligomers (macrolides) which contained more than three 3HB and 3HV repeating units. The degradation reactions of the linear and cyclic 3HB oligomers with the A. fumigatus depolymerase gave similar ratios of monomer-to-dimer products, but PHB itself formed mostly monomer on hydrolysis, indicating that the enzymatic hydrolysis reactions occurred by different mechanisms for these different types of substrates. The results of this study conclusively show that at least the endo mode of polymer hydrolysis occurs with the two enzymes studied, while the A. fumigatus depolymerase was found to utilize both endo and exo modes of hydrolysis to efficiently degrade PHB and 3HB oligomers.

  7. Optimization of enzymatic hydrolysis of cassava to obtain fermentable sugars.

    PubMed

    Collares, Renata M; Miklasevicius, Luiza V S; Bassaco, Mariana M; Salau, Nina P G; Mazutti, Marcio A; Bisognin, Dilson A; Terra, Lisiane M

    2012-07-01

    This work evaluates the enzymatic hydrolysis of starch from cassava using pectinase, α-amylase, and amyloglucosidase. A central composite rotational design (CCRD) was carried out to evaluate the effects of amyloglucosidase, pectinase, reaction time, and solid to liquid ratio. All the experiments were carried out in a bioreactor with working volume of 2 L. Approximately 98% efficiency hydrolysis was obtained, resulting in a concentration of total reducing sugar released of 160 g/L. It was concluded that pectinase improved the hydrolysis of starch from cassava. Reaction time was found to be significant until 7 h of reaction. A solid to liquid ratio of 1.0 was considered suitable for hydrolysis of starch from cassava. Amyloglucosidase was a significant variable in the process: after its addition to the reaction media, a 30%-50% increase in the amount of total reducing sugar released was observed. At optimal conditions the maximum productivity obtained was 22.9 g/(L·h).

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

    Treesearch

    Yang Huang; Shaolong Sun; Chen Huang; Qiang Yong; Thomas Elder; Maobing Tu

    2017-01-01

    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...

  9. Secretome analysis of Trichoderma reesei and Aspergillus niger cultivated by submerged and sequential fermentation processes: Enzyme production for sugarcane bagasse hydrolysis.

    PubMed

    Florencio, Camila; Cunha, Fernanda M; Badino, Alberto C; Farinas, Cristiane S; Ximenes, Eduardo; Ladisch, Michael R

    2016-08-01

    Cellulases and hemicellulases from Trichoderma reesei and Aspergillus niger have been shown to be powerful enzymes for biomass conversion to sugars, but the production costs are still relatively high for commercial application. The choice of an effective microbial cultivation process employed for enzyme production is important, since it may affect titers and the profile of protein secretion. We used proteomic analysis to characterize the secretome of T. reesei and A. niger cultivated in submerged and sequential fermentation processes. The information gained was key to understand differences in hydrolysis of steam exploded sugarcane bagasse for enzyme cocktails obtained from two different cultivation processes. The sequential process for cultivating A. niger gave xylanase and β-glucosidase activities 3- and 8-fold higher, respectively, than corresponding activities from the submerged process. A greater protein diversity of critical cellulolytic and hemicellulolytic enzymes were also observed through secretome analyses. These results helped to explain the 3-fold higher yield for hydrolysis of non-washed pretreated bagasse when combined T. reesei and A. niger enzyme extracts from sequential fermentation were used in place of enzymes obtained from submerged fermentation. An enzyme loading of 0.7 FPU cellulase activity/g glucan was surprisingly effective when compared to the 5-15 times more enzyme loadings commonly reported for other cellulose hydrolysis studies. Analyses showed that more than 80% consisted of proteins other than cellulases whose role is important to the hydrolysis of a lignocellulose substrate. Our work combined proteomic analyses and enzymology studies to show that sequential and submerged cultivation methods differently influence both titers and secretion profile of key enzymes required for the hydrolysis of sugarcane bagasse. The higher diversity of feruloyl esterases, xylanases and other auxiliary hemicellulolytic enzymes observed in the enzyme

  10. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

    SciTech Connect

    Alcantara, Maria Angeles Bermudez; Azadi, Parastoo; Garcia, Bruno Diez; Reyes-Sosa, Francisco Manuel

    2016-10-06

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

  11. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass

    DOE PAGES

    Alcantara, Maria Angeles Bermudez; Dobruchowska, Justyna; Azadi, Parastoo; ...

    2016-10-06

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. As a result, two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw.more » On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. In conclusion, this suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.« less

  12. Recalcitrant carbohydrates after enzymatic hydrolysis of pretreated lignocellulosic biomass.

    PubMed

    Alcántara, María Ángeles Bermúdez; Dobruchowska, Justyna; Azadi, Parastoo; García, Bruno Díez; Molina-Heredia, Fernando P; Reyes-Sosa, Francisco Manuel

    2016-01-01

    To reduce the cost of the enzymes for the hydrolysis of lignocellulosic biomass, two main strategies have been followed: one, the reduction of enzyme dosing by the use of more efficient and stable enzymatic cocktails; another, to include accessory enzymes in the cocktails to increase yields by reducing the recalcitrant carbohydrate fraction remaining at the end of the process. To guide this second strategy, we have explored the chemical bond composition of different fractions of recalcitrant carbohydrates after enzymatic hydrolysis. Two lignocellulosic feedstocks of relevance for the biofuels industry have been analyzed, corn stover and sugarcane straw. On comparing the composition of chemical bonds of the starting pretreated material with samples after standard and forced hydrolysis (with enzyme overdosing), we obtained similar sugar and chemical bond composition. This suggests that the current enzymatic cocktails bear the set of enzymes needed to hydrolyze these feedstocks. From our point of view, the results show the need for a parallel fine-tuning of the enzymatic cocktails with the pretreatment process to maximize sugar release yield.

  13. Factors impeding enzymatic wheat gluten hydrolysis at high solid concentrations.

    PubMed

    Hardt, N A; Janssen, A E M; Boom, R M; van der Goot, A J

    2014-07-01

    Enzymatic wheat gluten hydrolysis at high solid concentrations is advantageous from an environmental and economic point of view. However, increased wheat gluten concentrations result in a concentration effect with a decreased hydrolysis rate at constant enzyme-to-substrate ratios and a decreased maximum attainable degree of hydrolysis (DH%). We here identified the underlying factors causing the concentration effect. Wheat gluten was hydrolyzed at solid concentrations from 4.4% to 70%. The decreased hydrolysis rate was present at all solid concentrations and at any time of the reaction. Mass transfer limitations, enzyme inhibition and water activity were shown to not cause this hydrolysis rate limitation up to 50% solids. However, the hydrolysis rate limitation can be, at least partly, explained by a second-order enzyme inactivation process. Furthermore, mass transfer impeded the hydrolysis above 60% solids. Addition of enzyme after 24 h at high solid concentrations scarcely increased the DH%, suggesting that the maximum attainable DH% decreases at high solid concentrations. Reduced enzyme activities caused by low water activities can explain this DH% limitation. Finally, a possible influence of the plastein reaction on the DH% limitation is discussed.

  14. Changes in the structural properties and rate of hydrolysis of cotton fibers during extended enzymatic hydrolysis.

    PubMed

    Wang, Lushan; Zhang, Yuzhong; Gao, Peiji; Shi, Dongxia; Liu, Hongwen; Gao, Hongjun

    2006-02-20

    An extended enzymatic hydrolysis of cotton fibers by crude cellulase from Trichoderma pseudokoningii S-38 is described with characterization of both the enzyme changes of activities and cellulose structure. The hydrolysis rates declined drastically during the early stage and then slowly and steadily throughout the whole hydrolysis process the same trend could be seen during the following re-hydrolysis process. Morphological and structural changes to the fibers, such as swelling, frequent surface erosion, and variation in the packing and orientation of microfibrils, were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Observation of X-ray diffraction and IR spectra suggests that the hydrolysis process results in a gradual increase in the relative intensity of the hydrogen bond network, and a gradual decrease in the apparent crystal size of cellulose. The I(alpha) crystal phase was hydrolyzed more easily than was the I(beta) crystal phase. Apart from the inactivation of CBHs activity, changes in the packing and arrangement of microfibrils and the structural heterogeneity of cellulose during hydrolysis could be responsible for the reduction in the rate of reaction, especially in its later stages. The results indicate that the enzymatic hydrolysis of cellulose occurs on the outer layer of the fiber surface and that, following this, the process continues in a sub-layer manner.

  15. Enzymatic hydrolysis of fructans in the tequila production process.

    PubMed

    Avila-Fernández, Angela; Rendón-Poujol, Xóchitl; Olvera, Clarita; González, Fernando; Capella, Santiago; Peña-Alvarez, Araceli; López-Munguía, Agustín

    2009-06-24

    In contrast to the hydrolysis of reserve carbohydrates in most plant-derived alcoholic beverage processes carried out with enzymes, agave fructans in tequila production have traditionally been transformed to fermentable sugars through acid thermal hydrolysis. Experiments at the bench scale demonstrated that the extraction and hydrolysis of agave fructans can be carried out continuously using commercial inulinases in a countercurrent extraction process with shredded agave fibers. Difficulties in the temperature control of large extraction diffusers did not allow the scaling up of this procedure. Nevertheless, batch enzymatic hydrolysis of agave extracts obtained in diffusers operating at 60 and 90 degrees C was studied at the laboratory and industrial levels. The effects of the enzymatic process on some tequila congeners were studied, demonstrating that although a short thermal treatment is essential for the development of tequila's organoleptic characteristics, the fructan hydrolysis can be performed with enzymes without major modifications in the flavor or aroma, as determined by a plant sensory panel and corroborated by the analysis of tequila congeners.

  16. The mechanisms of plant cell wall deconstruction during enzymatic hydrolysis.

    PubMed

    Thygesen, Lisbeth G; Thybring, Emil E; Johansen, Katja S; Felby, Claus

    2014-01-01

    Mechanical agitation during enzymatic hydrolysis of insoluble plant biomass at high dry matter contents is indispensable for the initial liquefaction step in biorefining. It is known that particle size reduction is an important part of liquefaction, but the mechanisms involved are poorly understood. Here we put forward a simple model based on mechanical principles capable of capturing the result of the interaction between mechanical forces and cell wall weakening via hydrolysis of glucosidic bonds. This study illustrates that basic material science insights are relevant also within biochemistry, particularly when it comes to up-scaling of processes based on insoluble feed stocks.

  17. Effects of fibrillation on the wood fibers' enzymatic hydrolysis enhanced by mechanical refining.

    PubMed

    Liu, Wei; Wang, Bing; Hou, Qingxi; Chen, Wei; Wu, Ming

    2016-04-01

    The hardwood bleached kraft pulp (HBKP) fibers were pretreated by PFI mill to obtain the substrates, the effects of fibrillation on HBKP fibers' enzymatic hydrolysis was studied. The results showed that the enzymatic hydrolysis efficiency was enhanced obviously by mechanical refining. The mechanical refining alterated the fibers' characteristics such as fibrillation degree, specific surface area, swelling ability, crystallinity, fiber length and fines content. All these factors correlating to the enzymatic hydrolysis were evaluated through mathematical analysis. Among these factors, the fibrillation degree has the profoundest impact on the enzymatic hydrolysis of wood fibers. Consequently, the mechanical refining aiming for a high fibrillation degree was feasible to enhance the enzymatic hydrolysis of lignocellulosic biomass.

  18. Studies on the mechanism of enzymatic hydrolysis of cellulosic substances.

    PubMed

    Ghose, T K; Bisaria, V S

    1979-01-01

    Most cellulosic substances contain appreciable amounts of cellulose and hemicellulose, which on enzymatic hydrolysis mainly yield a mixture of glucose, cellobiose, and xylose. In this paper, studies on the mechanisms of hydrolysis of bagasse (a complex native cellulosic waste left after extraction of juice from cane sugar) by the cellulase enzyme components are described in light of their adsorption characteristics. Simultaneous adsorption of exo- and endoglucanases on hydrolyzable cellulosics is the causative factor of the hydrolysis that follows immediately after. It supports the postulate of synergistic enzyme action proposed by Eriksson. Xylanase pretreatment enhanced the hydrolysis of bagasse owing to the creation of more accessible cellulosic regions that are readily acted upon by exo- and endoglucanases. The synergistic action of the purified exoglucanase, endoglucanase, and xylanse has been found to be most effective for hydrolysis of bagasse but not for pure cellulose. Significant quantities of glucose are produced in beta-glucosidase-free cellulase action on bagasse. Individual and combined action of the purified cellulase components on hydrolysis of native and delignified bagasse are discussed in respect to the release of sugars in the hydrolysate.

  19. Determining yields in high solids enzymatic hydrolysis of biomass.

    PubMed

    Kristensen, Jan B; Felby, Claus; Jørgensen, Henning

    2009-05-01

    As technologies for utilizing biomass for fuel and chemical production continue to improve, enzymatic hydrolysis can be run at still higher solids concentrations. For hydrolyses that initially contain little or no free water (10-40% total solids, w/w), the saccharification of insoluble polymers into soluble sugars involves changes of volume, density, and proportion of insoluble solids. This poses a new challenge when determining the degree of hydrolysis (conversion yield). Experiments have shown that calculating the yield from the resulting sugar concentration in the supernatant of the slurry and using the assumed initial volume leads to significant overestimations of the yield. By measuring the proportion of insoluble solids in the slurry as well as the sugar concentration and specific gravity of the aqueous phase, it is possible to precisely calculate the degree of conversion. The discrepancies between the different ways of calculating yields are demonstrated along with a nonlaborious method for approximating yields in high solids hydrolysis.

  20. Kinetic studies of cellulose enzymatic hydrolysis from pretreated corn cob

    NASA Astrophysics Data System (ADS)

    Stevanie, Jeannie; Kartawiria, Irvan; Abimanyu, Haznan

    2017-01-01

    Successful utilization of corn cob biomass as raw material in bioethanol production is depending on the hydrolysis process where high level of β-cellulose is converted into glucose. Enzymatic hydrolysis is the common process for this purpose. This study is focusing on the evaluation of hydrolysis of pre-treated corn cob using Novozymes Cellic ® C-Tec2 and H-Tec2 enzymes to obtain the optimum reaction condition and its general reaction kinetics. The corn cob used was pretreated using 10% of NaOH solution. Hydrolysis reactions were conducted in 250 ml Erlenmeyer flask for 72 hour using mixture of C-Tec2 and H-Tec2 enzymes at the fixed ratio of 5:1 and glucose concentration were measured using HPLC. Reaction temperature of 40°C and quantity of 0.5 ml enzyme solution per gram substrate gives the highest reaction rate (0.0123 gram of glucose/gram sample.h) with the glucose yield being 0.089 g glucose/ g substrate. Total conversion of cellulose observed was 11.91 %. Corn cob hydrolysis using C-Tec2 and H-Tec2 enzymes also result in xylose (0.0202 g/g substrate), which can also contribute to bioethanol productivity in further fermentation process. The reaction is following zero order kinetics for the first 8 hours and reaches maximum yield within 10 hours; significantly shorter compared to previous studies of cellulosic material hydrolysis that may take up to 72 hour to complete. Prolonging the hydrolysis of pre-treated corn cob more than 24 hour gives no significant increase in glucose conversion and yield. Hydrolysis temperature range of 40°C to 60°C is in accordance with the manufacturer recommendation for the purpose; however the decrease of reaction rate is observable at temperature 50°C or higher.

  1. Alkaline polyol pulping and enzymatic hydrolysis of hardwood: effect of pulping severity and pulp composition on cellulase activity and overall sugar yield.

    PubMed

    Hundt, Martin; Schnitzlein, Klaus; Schnitzlein, Michael G

    2013-05-01

    The saccharification of beech wood using alkaline polyol pulping (AlkaPolP) and enzymatic hydrolysis was investigated. It will be demonstrated that the AlkaPolP process yields high quality pulps which can easily be hydrolyzed by cellulases. In order to find optimum reaction conditions chips of Fagus sylvatica were pretreated by alkaline glycerol at temperatures between 190 and 230 °C for 15, 20, and 25 min. The impacts of temperature and time were expressed using a severity factor R0. The dependencies of the conversion during enzymatic hydrolysis on severity, pulp yield, delignification and pulp composition are shown. In further experiments it was investigated if the sugar yields can be increased by the application of ultrasound or surfactants before enzyme addition. Up to 95% of the initial cellulose in wood were converted into glucose using cellulases from Trichoderma reesei and β-glucosidase from Aspergillus niger. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Determination of the number-average degree of polymerization of cellodextrins and cellulose with application to enzymatic hydrolysis.

    PubMed

    Zhang, Y-H Percival; Lynd, Lee R

    2005-01-01

    A rapid and accurate method for determining the number-average degree of polymerization (DP(n)) was established for insoluble cellulose and soluble cellodextrins as the ratio of glucosyl monomer concentration determined by the phenol-sulfuric acid method divided by the reducing-end concentration determined by a modified 2,2'-bicinchoninate (BCA) method. The modified BCA method, featuring incubation at 75 degrees C for 30 min, did not result in beta-glucosidic bond cleavage, whereas substantial cleavage was observed at higher temperature. Solubilization of insoluble cellulose in cold phosphoric acid prior to measurement of the reducing-end concentration by the BCA method was found not to be necessary for several model celluloses such as microcrystalline cellulose, but such solubilization was required for large fibers of cellulose such as Whatman No. 1 filter paper. The phenol-sulfuric acid method can be used for measuring the glucosyl monomer concentration of soluble cellodextrins, and also for insoluble cellulose if preceded by a liquefaction step. Standard deviations of < or =2% were obtained for both reducing and glucosyl monomer determination and of < or =3% for overall determination of DP. By use of the reported method, hydrolysis of phosphoric acid-swollen cellulose (PASC) by the Trichoderma reesei cellulase system was shown to result in a rapid decrease in DP as hydrolysis proceeded. By contrast, the DP of Avicel remained nearly constant during hydrolysis. The specific enzymatic cellulose hydrolysis rate is 100-fold higher for PASC as compared to Avicel.

  3. Structural modification of lignocellulosics by pretreatments to enhance enzymatic hydrolysis.

    PubMed

    Gharpuray, M M; Lee, Y H; Fan, L T

    1983-01-01

    In this work an evaluation was made of a wide variety of single and multiple pretreatment methods for enhancing the rate of enzymatic hydrolysis of wheat straw. A multiple pretreatment consisted of a physical pretreatment followed by a chemical pretreatment. The structural features of wheat straw, including the specific surface area, crystallinity index, and lignin content, were measured to understand the mechanism of the enhancement in the hydrolysis rate upon pretrement. It has been found that, in general, multiple pretreatments were not promising, since the hydrolysis rates rarely exceeded those achieved by single pretreatments. Ballmilling pretreatment was found to be effective in increasing the specific surface area and decreasing the crystallinity index. Treatment with ethylene glycol was highly effective in increasing the specific surface area, in addition to a high degree of delignification. Peracetic acid pretreatment was highly effective in delignifying substrate. Among multiple pretreatments, those involving peracetic acid treatment generally had lower crystallinity indices and lignin content values. The relationship between the hydrolysis rate and the set of structural features indicated that an increase in surface area and a decrease in the crystallinity and lignin content enhance the hydrolysis; the specific surface area is the most influential of the structural features, followed by the lignin content.

  4. The laccase-catalyzed modification of lignin for enzymatic hydrolysis.

    PubMed

    Moilanen, Ulla; Kellock, Miriam; Galkin, Sari; Viikari, Liisa

    2011-12-10

    The efficient use of cellulases in the hydrolysis of pretreated lignocellulosic biomass is limited due to the presence of lignin. Lignin is known to bind hydrolytic enzymes nonspecifically, thereby reducing their action on carbohydrate substrates. The composition and location of residual lignin therefore seem to be important for optimizing the enzymatic hydrolysis of lignocellulosic substrates. The use of lignin-modifying enzymes such as laccase may have potential in the modification or partial removal of lignin from the biomass. In this study, the effect of lignin modification by laccase on the hydrolysis of pretreated spruce (Picea abies) and giant reed (Arundo donax) was evaluated. The substrates were first treated with laccase and then hydrolyzed with commercial cellulases. Laccase modification improved the hydrolysis yield of spruce by 12%, but surprisingly had an adverse effect on giant reed, reducing the hydrolysis yield by 17%. The binding properties of cellulases on the untreated and laccase-treated lignins were further studied using isolated lignins. The laccase treatment reduced the binding of enzymes on modified spruce lignin, whereas with giant reed, the amount of bound proteins increased after laccase treatment. Further understanding of the reactions of laccase on lignin will help to control the unspecific-binding of cellulases on lignocellulosic substrates. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Glycosyl Cations versus Allylic Cations in Spontaneous and Enzymatic Hydrolysis.

    PubMed

    Danby, Phillip M; Withers, Stephen G

    2017-08-09

    Enzymatic prenyl and glycosyl transfer are seemingly unrelated reactions that yield molecules and protein modifications with disparate biological functions. However, both reactions employ diphosphate-activated donors and each proceed via cationic species: allylic cations and oxocarbenium ions, respectively. In this study, we explore the relationship between these processes by preparing valienyl ethers to serve as glycoside mimics that are capable of allylic rather than oxocarbenium cation stabilization. Rate constants for spontaneous hydrolysis of aryl glycosides and their analogous valienyl ethers were found to be almost identical, as were the corresponding activation enthalpies and entropies. This close similarity extended to the associated secondary kinetic isotope effects (KIEs), indicating very similar transition state stabilities and structures. Screening a library of over 100 β-glucosidases identified a number of enzymes that catalyze hydrolysis of these valienyl ethers with kcat values up to 20 s(-1). Detailed analysis of one such enzyme showed that ether hydrolysis occurs via the analogous mechanisms found for glycosides, and through a very similar transition state. This suggests that the generally lower rates of enzymatic cleavage of the cyclitol ethers reflects evolutionary specialization of these enzymes toward glycosides rather than inherent reactivity differences.

  6. Structural modifications of lignocellulosics by pretreatments to enhance enzymatic hydrolysis

    SciTech Connect

    Gharpuray, M.M.; Lee, Y.F.; Fan, L.T.

    1983-01-01

    In this work an evaluation was made of a wide variety of single and multiple pretreatment methods for enhancing the rate of enzymatic hydrolysis of wheat straw. A multiple pretreatment consisted of a physical pretreatment followed by a chemical pretreatment. The structural features of wheat straw, including the specific surface area, crystallinity index, and lignin content, were measured to understand the mechanism of the enhancement in the hyrolysis rate upon pretreatment. It has been found that, in general, multiple pretreatments were not promising, since the hydrolysis rates rarely exceeded those achieved by single pretreatments. Ball-milling pretreatment was found to be effective in increasing the specific surface area and decreasing the crystallinity index. Treatment with ethylene glycol was highly effective in increasing the specific surface area, in addition to a high degree of delignification. Peracetic acid pretreatment was highly effective in delignifying substrate. Among multiple pretreatments, those involving peracetic acid treatment generally had lower crystallinity indices and lignin content values. The relationship between the hydrolysis rate and the set of structural features indicated that an increase in surface area and a decrease in the crystallinity and lignin content enhance the hydrolysis; the specific surface area is the most influential of the structural features, followed by the lignin content. (Refs. 23).

  7. [Progress on cellulase and enzymatic hydrolysis of lignocellulosic biomass].

    PubMed

    Fang, Xu; Qin, Yuqi; Li, Xuezhi; Wang, Lushan; Wang, Tianhong; Zhu, Mingtian; Qu, Yinbo

    2010-07-01

    Biofuels and bio-based chemicals from lignocellulosic biomass are sustainable, making them alternatives to petroleum-derived fuels and chemicals to address the challenges of the shortage of crude oil supply and climate change resulted from the overconsumption of petroleum-based products, particularly in China. However, high cost in liberating sugars from lignocellulosic biomass is still the bottleneck of the commercialization of biofuels and bio-based chemicals. In this article, the major components of cellulases and their synergistic role in the hydrolysis of pre-treated biomass is reviewed, followed by how to evaluate the enzymatic hydrolysis. With the elucidation of the underlying mechanism of the conformations of the enzyme molecules and their effectiveness in attacking cellulose substrate, more efficient enzymes are expected to be developed. Using the high production strain Penicillium decumbens, the on-site production of cellulases for cellulose ethanol production is discussed.

  8. Bioabatement with hemicellulase supplementation to reduce enzymatic hydrolysis inhibitors.

    PubMed

    Cao, Guangli; Ximenes, Eduardo; Nichols, Nancy N; Frazer, Sarah E; Kim, Daehwan; Cotta, Michael A; Ladisch, Michael

    2015-08-01

    A stepwise removal of inhibitory compounds by bioabatement combined with hemicellulase supplementation was conducted to enhance cellulose hydrolysis of liquid hot water-pretreated corn stover. Results showed that the fungus Coniochaeta ligniaria NRRL30616 eliminated most of the enzyme and fermentation inhibitors from liquid hot water-pretreated corn stover hydrolysates. Moreover, addition of hemicellulases after bioabatement and before enzymatic hydrolysis of cellulose achieved 20% higher glucose yields compared to non-treated samples. This work presents the mechanisms by which supplementation of the fungus with hemicellulase enzymes enables maximal conversion, and confirms the inhibitory effect of xylo-oligosaccharides in corn stover hydrolysates once the dominant inhibitory effect of phenolic compounds is removed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Alcohol fermentation of sweet potato. Membrane reactor in enzymatic hydrolysis

    SciTech Connect

    Azhar, A.; Hamdy, M.K.

    1981-06-01

    Use of ultrafiltration membrane systems in stirred cell and in thin-channel systems for immobilizing enzyme (sweet potato intrinsic and crystalline /beta/-amylase) in hydrolysis of sweet potato through a continuous operation mode were studied. Both the filtration rate and reducing sugars, produced as the result of enzymatic hydrolysis, decreased with the filtration time. THe immobilized enzymes in the thin-channel system showed a much better performance compared to that in the stirred cell system. Addition of crystalline sweet potato /beta/-amylase to the sweet potato increased both the filtration rate and reducing-sugars content. Alcoholic fermentation of the filtrate resulted in an alcohol content of 4.2%. This represented fermentation of 95% of the sugars with an efficiency of 88%. 17 refs.

  10. Ultrasound-enhanced enzymatic hydrolysis of poly(ethylene terephthalate).

    PubMed

    Pellis, Alessandro; Gamerith, Caroline; Ghazaryan, Gagik; Ortner, Andreas; Herrero Acero, Enrique; Guebitz, Georg M

    2016-10-01

    The application of ultrasound was found to enhance enzymatic hydrolysis of poly(ethylene terephthalate) (PET). After a short activation phase up to 6.6times increase in the amount of released products was found. PET powder with lower crystallinity of 8% was hydrolyzed faster when compared to PET with 28% crystallinity. Ultrasound activation was found to be around three times more effective on powders vs. films most likely due to a larger surface area accessible to the enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Effect of non-enzymatic proteins on enzymatic hydrolysis and simultaneous saccharification and fermentation of different lignocellulosic materials.

    PubMed

    Wang, Hui; Kobayashi, Shinichi; Mochidzuki, Kazuhiro

    2015-08-01

    Non-enzymatic proteins were added during hydrolysis of cellulose and simultaneous saccharification and fermentation (SSF) of different biomass materials. Bovine serum albumin (BSA), a model non-enzymatic protein, increased cellulose and xylose conversion efficiency and also enhanced the ethanol yield during SSF of rice straw subjected to varied pretreatments. Corn steep liquor, yeast extract, and peptone also exerted a similar effect as BSA and enhanced the enzymatic hydrolysis of rice straw. Compared to the glucose yields obtained after enzymatic hydrolysis of rice straw in the absence of additives, the glucose yields after 72h of hydrolysis increased by 12.7%, 13.5%, and 13.7% after addition of the corn steep liquor, yeast extract, and peptone, respectively. This study indicated the use of BSA as an alternative to intensive pretreatment of lignocellulosic materials for enhancing enzymatic digestibility. The utilization of non-enzymatic protein additives is promising for application in glucose and ethanol production from lignocellulosic materials.

  12. Expression of three Trichoderma reesei cellulase genes in Saccharomyces pastorianus for the development of a two-step process of hydrolysis and fermentation of cellulose.

    PubMed

    Fitzpatrick, J; Kricka, W; James, T C; Bond, U

    2014-07-01

    To compare the production of recombinant cellulase enzymes in two Saccharomyces species so as to ascertain the most suitable heterologous host for the degradation of cellulose-based biomass and its conversion into bioethanol. cDNA copies of genes representing the three major classes of cellulases (Endoglucanases, Cellobiohydrolases and β-glucosidases) from Trichoderma reesei were expressed in Saccharomyces pastorianus and Saccharomyces cerevisiae. The recombinant enzymes were secreted by the yeast hosts into the medium and were shown to act in synergy to hydrolyse cellulose. The conditions required to achieve maximum release of glucose from cellulose by the recombinant enzymes were defined and the activity of the recombinant enzymes was compared to a commercial cocktail of T. reesei cellulases. We demonstrate that significantly higher levels of cellulase activity were achieved by expression of the genes in S. pastorianus compared to S. cerevisiae. Hydrolysis of cellulose by the combined activity of the recombinant enzymes was significantly better at 50°C than at 30°C, the temperature used for mesophilic yeast fermentations, reflecting the known temperature profiles of the native enzymes. The results demonstrate that host choice is important for the heterologous production of cellulases. On the basis of the low activity of the T. reesei recombinant enzymes at fermentation temperatures, we propose a two-step process for the hydrolysis of cellulose and its fermentation into alcohol using cellulases produced in situ. © 2014 The Society for Applied Microbiology.

  13. Degradation of Opioids and Opiates During Acid Hydrolysis Leads to Reduced Recovery Compared to Enzymatic Hydrolysis.

    PubMed

    Sitasuwan, Pongkwan; Melendez, Cathleen; Marinova, Margarita; Mastrianni, Kaylee R; Darragh, Alicia; Ryan, Emily; Lee, L Andrew

    2016-10-01

    Drug monitoring laboratories utilize a hydrolysis process to liberate the opiates from their glucuronide conjugates to facilitate their detection by tandem mass spectrometry (MS). Both acid and enzyme hydrolysis have been reported as viable methods, with the former as a more effective process for recovering codeine-6-glucuronide and morphine-6-glucuronide. Here, we report concerns with acid-catalyzed hydrolysis of opioids, including a significant loss of analytes and conversions of oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine. The acid-catalyzed reaction was monitored in neat water and patient urine samples by liquid chromatography-time-of-flight and tandem MS. These side reactions with acid hydrolysis may limit accurate quantitation due to loss of analytes, possibly lead to false positives, and poorly correlate with pharmacogenetic profiles, as cytochrome P450 enzyme (CYP2D6) is often involved with oxycodone to oxymorphone, hydrocodone to hydromorphone and codeine to morphine conversions. Enzymatic hydrolysis process using the purified, genetically engineered β-glucuronidase (IMCSzyme(®)) addresses many of these concerns and demonstrates accurate quantitation and high recoveries for oxycodone, hydrocodone, oxymorphone and hydromorphone.

  14. Enzymatic saccharification of pretreated wheat straw: comparison of solids-recycling, sequential hydrolysis and batch hydrolysis.

    PubMed

    Pihlajaniemi, Ville; Sipponen, Satu; Sipponen, Mika H; Pastinen, Ossi; Laakso, Simo

    2014-02-01

    In the enzymatic hydrolysis of lignocellulose materials, the recycling of the solid residue has previously been considered within the context of enzyme recycling. In this study, a steady state investigation of a solids-recycling process was made with pretreated wheat straw and compared to sequential and batch hydrolysis at constant reaction times, substrate feed and liquid and enzyme consumption. Compared to batch hydrolysis, the recycling and sequential processes showed roughly equal hydrolysis yields, while the volumetric productivity was significantly increased. In the 72h process the improvement was 90% due to an increased reaction consistency, while the solids feed was 16% of the total process constituents. The improvement resulted primarily from product removal, which was equally efficient in solids-recycling and sequential hydrolysis processes. No evidence of accumulation of enzymes beyond the accumulation of the substrate was found in recycling. A mathematical model of solids-recycling was constructed, based on a geometrical series. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Enzymatic hydrolysis, adsorption, and recycling during hydrolysis of bagasse sulfite pulp.

    PubMed

    Ouyang, Jia; Liu, Baotian; Zhang, Min; Zheng, Zhaojuan; Yu, Heng

    2013-10-01

    The high costs of enzymatic hydrolysis along with the high enzyme dosage are often considered as the major bottlenecks in lignocellulosic bioconversion. This study investigated the hydrolysis efficiency, cellulase adsorption and enzyme recycling during the hydrolysis of bagasse sulfite pulp (BSP). After 48 h of hydrolysis, more than 70% of the cellulose was hydrolyzed, while the protein concentration and cellulase activity in solution remained 31% and 17% of the initial value, respectively. The cellulase adsorption on the fresh BSP was better fitted by a Sips model, suggesting the occurrence of a multilayer adsorption at low cellulase concentration and monolayer adsorption at high concentration on the BSP surfaces. Desorption profile studies showed that the optimum desorption condition was at pH 4.8 and 40 °C. Moreover, considering the limited ability to desorption, directly empolying the bound enzyme with residual substrate is more effective method to recover cellulase during the hydrolysis of BSP. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  16. Cellulose hydrolysis by the cellulases from Trichoderma reesei: adsorptions of two cellobiohydrolases, two endocellulases and their core proteins on filter paper and their relation to hydrolysis.

    PubMed Central

    Nidetzky, B; Steiner, W; Claeyssens, M

    1994-01-01

    Separate binding of several purified cellulolytic components of Trichoderma reesei on to filter paper was studied and concomitant hydrolysis rates evaluated. Enhancement of mass transfer from the bulk liquid to the solid substrate by agitation has two different effects on adsorption depending on the type of enzyme: (i) the fraction of cellobiohydrolase II (CBH II) and endoglucanase III (EG III) bound at equilibrium is increased, whereas (ii) the rate but not the extent of cellobiohydrolase I (CBH I) and endoglucanase I (EG I) adsorption is affected. The adsorption of CBH I core, a component lacking the cellulose-binding domain (CBD), is, however, not significantly influenced by mass transfer. The CBH I interdomain peptide (present in CBH I core b) does not participate in adsorption but enhances stability. The adsorption of CBH I core proteins is a fully reversible process whereas that of the intact CBH I is not. Thus, the interaction of the CBD with filter paper apparently accounts for the mass-transfer-limited binding rate and also for the irreversible adsorption of intact CBH I. Adsorption isotherms at 50 degrees C indicate very similar relative association constants for the intact cellulases (0.24-0.30 l/g of cellulose), but drastically reduced values for CBH I core proteins (0.03 l/g of cellulose). The specific activities of adsorbed CBH I and of its core proteins are identical and a linear relationship between adsorption and rates of hydrolysis is found only for these enzymes. Thus, non-productive binding on to cellulose seems evident in the case of CBH II and EG III but not CBH I. PMID:7980450

  17. Effect of enzymatic hydrolysis on native starch granule structure.

    PubMed

    Blazek, Jaroslav; Gilbert, Elliot Paul

    2010-12-13

    Enzymatic digestion of six starches of different botanical origin was studied in real time by in situ time-resolved small-angle neutron scattering (SANS) and complemented by the analysis of native and digested material by X-ray diffraction, differential scanning calorimetry, small-angle X-ray scattering, and scanning electron microscopy with the aim of following changes in starch granule nanostructure during enzymatic digestion. This range of techniques enables coverage over five orders of length-scale, as is necessary for this hierarchically structured material. Starches studied varied in their digestibility and displayed structural differences in the course of enzymatic digestion. The use of time-resolved SANS showed that solvent-drying of digested residues does not induce any structural artifacts on the length scale followed by small-angle scattering. In the course of digestion, the lamellar peak intensity gradually decreased and low-q scattering increased. These trends were more substantial for A-type than for B-type starches. These observations were explained by preferential digestion of the amorphous growth rings. Hydrolysis of the semicrystalline growth rings was explained on the basis of a liquid-crystalline model for starch considering differences between A-type and B-type starches in the length and rigidity of amylopectin spacers and branches. As evidenced by differing morphologies of enzymatic attack among varieties, the existence of granular pores and channels and physical penetrability of the amorphous growth ring affect the accessibility of the enzyme to the substrate. The combined effects of the granule microstructure and the nanostructure of the growth rings influence the opportunity of the enzyme to access its substrate; as a consequence, these structures determine the enzymatic digestibility of granular starches more than the absolute physical densities of the amorphous growth rings and amorphous and crystalline regions of the semicrystalline

  18. Enzymatic catalyzed palm oil hydrolysis under ultrasound irradiation: diacylglycerol synthesis.

    PubMed

    Awadallak, Jamal A; Voll, Fernando; Ribas, Marielen C; da Silva, Camila; Filho, Lucio Cardozo; da Silva, Edson A

    2013-07-01

    Diacylglycerol (DAG) rich oils have an organoleptic property like that of regular edible oils, but these oils do not tend to be accumulated as fat. Palm oil ranks first in the world in terms of edible oil production owing to its low cost. The aim of this study was to propose a new methodology to produce diacylglycerol by hydrolysis of palm oil using Lipozyme RM IM commercial lipase as a catalyst under ultrasound irradiation. The reactions were carried out at 55 °C with two different methods. First, the reaction system was exposed to ultrasonic waves for the whole reaction time, which led to enzymatic inactivation and water evaporation. Ultrasound was then used to promote emulsification of the water/oil system before the hydrolysis reaction, avoiding contact between the probe and the enzymes. An experimental design was used to optimize the ultrasound-related parameters and maximize the hydrolysis rate, and in these conditions, with a change in equilibrium, DAG production was evaluated. Better reaction conditions were achieved for the second method: 11.20 wt.% (water+oil mass) water content, 1.36 wt.% (water+oil mass) enzyme load, 12 h of reaction time, 1.2 min and 200 W of exposure to ultrasound. In these conditions diacylglycerol yield was 34.17 wt.%.

  19. Enzymatic hydrolysis of defatted mackerel protein with low bitter taste

    NASA Astrophysics Data System (ADS)

    Hou, Hu; Li, Bafang; Zhao, Xue

    2011-03-01

    Ultrasound-assisted solvent extraction was confirmed as a novel, effective method for separating lipid from mackerel protein, resulting in a degreasing rate (DR) of 95% and a nitrogen recovery (NR) of 88.6%. To obtain protein hydrolysates with high nitrogen recovery and low bitter taste, enzymatic hydrolysis was performed using eight commercially available proteases. It turned out that the optimum enzyme was the `Mixed enzymes for animal proteolysis'. An enzyme dosage of 4%, a temperature of 50°, and a hydrolysis time of 300 min were found to be the optimum conditions to obtain high NR (84.28%) and degree of hydrolysis (DH, 16.18%) by orthogonal experiments. Glutamic acid was the most abundant amino acid of MDP (defatted mackerel protein) and MDPH (defatted mackerel protein hydrolysates). Compared with the FAO/WHO reference protein, the essential amino acid chemical scores (CS) were greater than 1.0 (1.0-1.7) in MDPH, which is reflective of high nutritional value. This, coupled with the light color and slight fishy odor, indicates that MDPH would potentially have a wide range of applications such as nutritional additives, functional ingredients, and so on.

  20. Periodic peristalsis releasing constrained water in high solids enzymatic hydrolysis of steam exploded corn stover.

    PubMed

    Liu, Zhi-Hua; Chen, Hong-Zhang

    2016-04-01

    Periodic peristalsis was used to release water constraint and increase high solids enzymatic hydrolysis efficiency. Glucan and xylan conversion in periodic peristalsis enzymatic hydrolysis (PPEH) at 21% solid loading increased by 5.2-6.4% and 6.8-8.8% compared with that in incubator shaker enzymatic hydrolysis (ISEH), respectively. Hydrolysis kinetics suggested that sugars conversion significantly increased within 24h in PPEH compared with ISEH. The peak height of main water pool increased by 7.7-43.1% within 24h in PPEH compared with ISEH. The increases in peak height of main water pool were consistent with the increases in glucan conversion. Submicroscopic particulates and macro granule residues contributed greatly to water constraint compared with glucose, xylose, ethanol, and Tween 80. Smaller particle size and longer residence time resulted in lower water constraint and facilitated the enzymatic hydrolysis performance. Periodic peristalsis was an effective method to reduce water constraint and increase high solids enzymatic hydrolysis efficiency.

  1. Free Energy Diagram for the Heterogeneous Enzymatic Hydrolysis of Glycosidic Bonds in Cellulose.

    PubMed

    Sørensen, Trine Holst; Cruys-Bagger, Nicolaj; Borch, Kim; Westh, Peter

    2015-09-04

    Kinetic and thermodynamic data have been analyzed according to transition state theory and a simplified reaction scheme for the enzymatic hydrolysis of insoluble cellulose. For the cellobiohydrolase Cel7A from Hypocrea jecorina (Trichoderma reesei), we were able to measure or collect relevant values for all stable and activated complexes defined by the reaction scheme and hence propose a free energy diagram for the full heterogeneous process. For other Cel7A enzymes, including variants with and without carbohydrate binding module (CBM), we obtained activation parameters for the association and dissociation of the enzyme-substrate complex. The results showed that the kinetics of enzyme-substrate association (i.e. formation of the Michaelis complex) was almost entirely entropy-controlled and that the activation entropy corresponded approximately to the loss of translational and rotational degrees of freedom of the dissolved enzyme. This implied that the transition state occurred early in the path where the enzyme has lost these degrees of freedom but not yet established extensive contact interactions in the binding tunnel. For dissociation, a similar analysis suggested that the transition state was late in the path where most enzyme-substrate contacts were broken. Activation enthalpies revealed that the rate of dissociation was far more temperature-sensitive than the rates of both association and the inner catalytic cycle. Comparisons of one- and two-domain variants showed that the CBM had no influence on the transition state for association but increased the free energy barrier for dissociation. Hence, the CBM appeared to promote the stability of the complex by delaying dissociation rather than accelerating association.

  2. Free Energy Diagram for the Heterogeneous Enzymatic Hydrolysis of Glycosidic Bonds in Cellulose*

    PubMed Central

    Sørensen, Trine Holst; Cruys-Bagger, Nicolaj; Borch, Kim; Westh, Peter

    2015-01-01

    Kinetic and thermodynamic data have been analyzed according to transition state theory and a simplified reaction scheme for the enzymatic hydrolysis of insoluble cellulose. For the cellobiohydrolase Cel7A from Hypocrea jecorina (Trichoderma reesei), we were able to measure or collect relevant values for all stable and activated complexes defined by the reaction scheme and hence propose a free energy diagram for the full heterogeneous process. For other Cel7A enzymes, including variants with and without carbohydrate binding module (CBM), we obtained activation parameters for the association and dissociation of the enzyme-substrate complex. The results showed that the kinetics of enzyme-substrate association (i.e. formation of the Michaelis complex) was almost entirely entropy-controlled and that the activation entropy corresponded approximately to the loss of translational and rotational degrees of freedom of the dissolved enzyme. This implied that the transition state occurred early in the path where the enzyme has lost these degrees of freedom but not yet established extensive contact interactions in the binding tunnel. For dissociation, a similar analysis suggested that the transition state was late in the path where most enzyme-substrate contacts were broken. Activation enthalpies revealed that the rate of dissociation was far more temperature-sensitive than the rates of both association and the inner catalytic cycle. Comparisons of one- and two-domain variants showed that the CBM had no influence on the transition state for association but increased the free energy barrier for dissociation. Hence, the CBM appeared to promote the stability of the complex by delaying dissociation rather than accelerating association. PMID:26183776

  3. Enhancement of enzymatic hydrolysis of cellulose by surfactant

    SciTech Connect

    Ooshima, H.; Sakata, M.; Harano, Y.

    1986-01-01

    Effects of surfactants on enzymatic saccharification of cellulose have been studied. Nonionic, amphoteric, and cationic surfactants enhanced the saccharification, while anionic surfactant did not. Cationic and anionic surfactants denatured cellulase in their relatively low concentrations, namely, more than 0.008 and 0.001%, respectively. Using nonionic surfactant Tween 20, which is most effective to the enhancement (e.g., the fractional conversion attained by 72 h saccharification of 5 wt % Avicel in the presence of 0.05 wt % Tween 20 is increased by 35%), actions of surfactant have been examined. As the results, it was suggested that Tween 20 plays an important role in the hydrolysis of crystalline cellulose and that Tween 20 disturbs the adsorption of endoglucanase on cellulose, i.e., varies the adsorption balance of endo- and exoglucanase, resulting in enhancing the reaction. The influence of Tween 20 to the saccharification was found to remain in simultaneous saccharification and fermentation of Avicel.

  4. Sodium hydroxide pretreatment and enzymatic hydrolysis of coastal Bermuda grass.

    PubMed

    Wang, Ziyu; Keshwani, Deepak R; Redding, Arthur P; Cheng, Jay J

    2010-05-01

    Coastal Bermuda grass was pretreated with NaOH at concentrations from 0.5% to 3% (w/v) for a residence time from 15 to 90min at 121 degrees C. The pretreatments were evaluated based on total lignin removal and production of total reducing sugars, glucose and xylose from enzymatic hydrolysis of the pretreated biomass. Up to 86% lignin removal was observed. The optimal NaOH pretreatment conditions at 121 degrees C for total reducing sugars production as well as glucose and xylose yields are 15min and 0.75% NaOH. Under these optimal pretreatment conditions, total reducing sugars yield was about 71% of the theoretical maximum, and the overall conversion efficiencies for glucan and xylan were 90.43% and 65.11%, respectively.

  5. The effect of high intensity mixing on the enzymatic hydrolysis of concentrated cellulose fiber suspensions

    Treesearch

    Joseph R. Samaniuk; C. Tim Scott; Thatcher W. Root; Daniel J. Klingenberg

    2011-01-01

    Enzymatic hydrolysis of lignocellulosic biomass in a high shear environment was examined. The conversion of cellulose to glucose in samples mixed in a torque rheometer producing shear flows similar to those found in twin screw extruders was greater than that of unmixed samples. In addition, there is a synergistic effect of mixing and enzymatic hydrolysis; mixing...

  6. Effects of lignin-metal complexation on enzymatic hydrolysis of cellulose

    Treesearch

    H. Liu; Junyong Zhu; S.Y. Fu

    2010-01-01

    This study investigated the inhibition of enzymatic hydrolysis by unbound lignin (soluble and insoluble) with or without the addition of metal compounds. Sulfonated, Organosolv, and Kraft lignin were added in aqueous enzyme-cellulose systems at different concentrations before hydrolysis. The measured substrate enzymatic digestibility (SED) of cellulose was decreased by...

  7. Chemical structures of corn stover and its residue after dilute acid prehydrolysis and enzymatic hydrolysis: Insight into factors limiting enzymatic hydrolysis

    USDA-ARS?s Scientific Manuscript database

    Advanced solid-state NMR techniques and wet chemical analyses were applied to investigate untreated corn stover (UCS) and its residues after dilute acid prehydrolysis (DAP) and enzymatic hydrolysis (RES) to provide evidence for the limitations to the effectiveness of enzyme hydrolysis. Advanced soli...

  8. Effect of inhibitors released during steam-explosion pretreatment of barley straw on enzymatic hydrolysis.

    PubMed

    García-Aparicio, Ma Prado; Ballesteros, Ignacio; González, Alberto; Oliva, José Miguel; Ballesteros, Mercedes; Negro, Ma José

    2006-01-01

    The influence of the liquid fraction (prehydrolysate) generated during steam-explosion pretreatment (210 degrees C, 15 min) of barley straw on the enzymatic hydrolysis was determined. Prehydrolysate was analyzed for degradation compounds and sugars' content and used as a medium for enzymatic hydrolysis tests after pH adjusting to 4.8. Our results show that the presence of the compounds contained in the prehydrolysate strongly affects the hydrolysis step (a 25% decrease in cellulose conversion compared with control). Sugars are shown to be more potent inhibitors of enzymatic hydrolysis than degradation products.

  9. Influence of substrate particle size and wet oxidation on physical surface structures and enzymatic hydrolysis of wheat straw.

    PubMed

    Pedersen, Mads; Meyer, Anne S

    2009-01-01

    In the worldwide quest for producing biofuels from lignocellulosic biomass, the importance of the substrate pretreatment is becoming increasingly apparent. This work examined the effects of reducing the substrate particle sizes of wheat straw by grinding prior to wet oxidation and enzymatic hydrolysis. The yields of glucose and xylose were assessed after treatments with a benchmark cellulase system consisting of Celluclast 1.5 L (Trichoderma reesei) and Novozym 188 beta-glucosidase (Aspergillus niger). Both wet oxidized and not wet oxidized wheat straw particles gave increased glucose release with reduced particle size. After wet oxidation, the glucose release from the smallest particles (53-149 mum) reached 90% of the theoretical maximum after 24 h of enzyme treatment. The corresponding glucose release from the wet oxidized reference samples (2-4 cm) was approximately 65% of the theoretical maximum. The xylose release only increased (by up to 39%) with particle size decrease for the straw particles that had not been wet oxidized. Wet oxidation pretreatment increased the enzymatic xylose release by 5.4 times and the glucose release by 1.8 times across all particle sizes. Comparison of scanning electron microscopy images of the straw particles revealed edged, nonspherical, porous particles with variable surface structures as a result of the grinding. Wet oxidation pretreatment tore up the surface structures of the particles to retain vascular bundles of xylem and phloem. The enzymatic hydrolysis left behind a significant amount of solid, apparently porous structures within all particles size groups of both the not wet oxidized and wet oxidized particles.

  10. Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling.

    PubMed

    Weiss, Noah; Börjesson, Johan; Pedersen, Lars Saaby; Meyer, Anne S

    2013-01-21

    It is necessary to develop efficient methods to produce renewable fuels from lignocellulosic biomass. One of the main challenges to the industrialization of lignocellulose conversion processes is the large amount of cellulase enzymes used for the hydrolysis of cellulose. One method for decreasing the amount of enzyme used is to recycle the enzymes. In this study, the recycle of enzymes associated with the insoluble solid fraction after the enzymatic hydrolysis of cellulose was investigated for pretreated corn stover under a variety of recycling conditions. It was found that a significant amount of cellulase activity could be recovered by recycling the insoluble biomass fraction, and the enzyme dosage could be decreased by 30% to achieve the same glucose yields under the most favorable conditions. Enzyme productivity (g glucose produced/g enzyme applied) increased between 30 and 50% by the recycling, depending on the reaction conditions. While increasing the amount of solids recycled increased process performance, the methods applicability was limited by its positive correlation with increasing total solids concentrations, reaction volumes, and lignin content of the insoluble residue. However, increasing amounts of lignin rich residue during the recycle did not negatively impact glucose yields. To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzyme usage, and research should be continued for its industrial application.

  11. Enzymatic Hydrolysis of Organic Phosphorus in River Bed Sediments

    NASA Astrophysics Data System (ADS)

    Wang, J.; Pant, H. K.

    2009-12-01

    Enzymatic hydrolysis of phosphorus (P) in bed sediments is an important process that maintains bioavailable P in the river systems. The P bioavailability is the criteria for assessing the eutrophication potential in rivers and streams. The objective of this research was to determine potential bioavailability of organic P (OP) in the Bronx River bed sediments using native phosphatases (NP) and phosphodiesterase (PDEase) hydrolysis. The bed sediments collected in summer 2006 and 2007 were incubated at 37C for 6 h at pH 7.5 with NP. The results showed that NP hydrolyzed substantial amount of OP (up to 76%) under favorable temperature and pH, indicating OP could be hydrolyzed under increased temperature, in turn, increase in P availability in the river. Similarly, the sediments incubated with PDEase under 37C at pH 8.8, the results showed that up to 82% of OP could be hydrolyzed. Strong correlations between percentage of OP hydrolyzed by PDEase and organic matter (OM) were observed for sediments collected in 2006 (r = 0.745; p≤0.01) and 2007 (r = 0.724; p≤0.01), indicating PDEase hydrolysable P is mainly with organic matter. The local hydro-climatic changes such as temperature increase and pH could hydrolyze substantial amount of OP and increase bioavailable P in water column, resulting in potential threat to the river ecosystems.

  12. Enzymatic hydrolysis of organic phosphorus in swine manure and soil.

    PubMed

    He, Zhongqi; Griffin, Timothy S; Honeycutt, C Wayne

    2004-01-01

    Organic phosphorus (Po) exists in many chemical forms that differ in their susceptibility to hydrolysis and, therefore, bioavailability to plants and microorganisms. Identification and quantification of these forms may significantly contribute to effective agricultural P management. Phosphatases catalyze reactions that release orthophosphate (Pi) from Po compounds. Alkaline phosphatase in tris-HCl buffer (pH 9.0), wheat (Triticum aestivum L.) phytase in potassium acetate buffer (pH 5.0), and nuclease P1 in potassium acetate buffer (pH 5.0) can be used to classify and quantify Po in animal manure. Background error associated with different pH and buffer systems is observed. In this study, we improved the enzymatic hydrolysis approach and tested its applicability for investigating Po in soils, recognizing that soil and manure differ in numerous physicochemical properties. We applied (i) acid phosphatase from potato (Solanum tuberosum L.), (ii) acid phosphatases from both potato and wheat germ, and (iii) both enzymes plus nuclease P1 to identify and quantify simple labile monoester P, phytate (myo-inositol hexakis phosphate)-like P, and DNA-like P, respectively, in a single pH/buffer system (100 mM sodium acetate, pH 5.0). This hydrolysis procedure released Po in sequentially extracted H2O, NaHCO3, and NaOH fractions of swine (Sus scrofa) manure, and of three sandy loam soils. Further refinement of the approach may provide a universal tool for evaluating hydrolyzable Po from a wide range of sources.

  13. The effect of crystallinity of cellulose on the rate of reducing sugars production by heterogeneous enzymatic hydrolysis.

    PubMed

    Al-Zuhair, Sulaiman

    2008-07-01

    A kinetic model is devised, from the reaction mechanism steps, to predict the rate of reducing sugar production by hydrolysis of two types of cellulose, namely, amorphous carboxymethylcellulose (CMC) and highly crystalline wood shavings, using Aspergillus niger cellulase. Experimental results in a stirred batch reactor at 40 degrees C show that the production of reducing sugar reduced at much shorter times for wood shavings in comparison to CMC at the same initial substrate concentration. The experimental results are used to determine the kinetic parameters of the model equations. The significance of crystallinity was determined using inert fraction coefficient, which is assumed to be constant and equals 0.05 and 0.98 for CMC and wood shavings, respectively. It is shown there is a good agreement between the experimental results and proposed kinetic model predictions. The effect of the inert fraction coefficient on the production of reducing sugar by the enzymatic hydrolysis of cellulose is also determined. It is found that the cellulase used extracted from A. niger is much more sensitive towards the substrate structure in comparison to that extracted from Trichoderma reesei.

  14. A modified expression of the major hydrolase activator in Hypocrea jecorina (Trichoderma reesei) changes enzymatic catalysis of biopolymer degradation.

    PubMed

    Pucher, Marion E; Steiger, Matthias G; Mach, Robert L; Mach-Aigner, Astrid R

    2011-06-10

    Hypocrea jecorina (anamorph Trichoderma reesei) is a saprophytic fungus that produces hydrolases, which are applied in different types of industries and used for the production of biofuel. A recombinant Hypocrea strain, which constantly expresses the main transcription activator of hydrolases (Xylanase regulator 1), was found to grow faster on xylan and its monomeric backbone molecule d-xylose. This strain also showed improved ability of clearing xylan medium on plates. Furthermore, this strain has a changed transcription profile concerning genes encoding for hydrolases and enzymes associated with degradation of (hemi)celluloses. We demonstrated that enzymes of this strain from a xylan cultivation favoured break down of hemicelluloses to the monomer d-xylose compared to the parental strain, while the enzymes of the latter one formed more xylobiose. Applying supernatants from cultivation on carboxymethylcellulose in enzymatic conversion of hemicelluloses, the enzymes of the recombinant strain were clearly producing more of both, d-xylose and xylobiose, compared to the parental strain. Altogether, these results point to a changed hydrolase expression profile, an enhanced capability to form the xylan-monomer d-xylose and the assumption that there is a disordered induction pattern if the Xylanase regulator 1 is de-regulated in Hypocrea.

  15. Truncation of a mannanase from Trichoderma harzianum improves its enzymatic properties and expression efficiency in Trichoderma reesei.

    PubMed

    Wang, Juan; Zeng, Desheng; Liu, Gang; Wang, Shaowen; Yu, Shaowen

    2014-01-01

    To obtain high expression efficiency of a mannanase gene, ThMan5A, cloned from Trichoderma harzianum MGQ2, both the full-length gene and a truncated gene (ThMan5AΔCBM) that contains only the catalytic domain, were expressed in Trichoderma reesei QM9414 using the strong constitutive promoter of the gene encoding pyruvate decarboxylase (pdc), and purified to homogeneity, respectively. We found that truncation of the gene improved its expression efficiency as well as the enzymatic properties of the encoded protein. The recombinant strain expressing ThMan5AΔCBM produced 2,460 ± 45.1 U/ml of mannanase activity in the culture supernatant; 2.3-fold higher than when expressing the full-length ThMan5A gene. In addition, the truncated mannanase had superior thermostability compared with the full-length enzyme and retained 100 % of its activity after incubation at 60 °C for 48 h. Our results clearly show that the truncated ThMan5A enzyme exhibited improved characteristics both in expression efficiency and in its thermal stability. These characteristics suggest that ThMan5AΔCBM has potential applications in the food, feed, paper, and pulp industries.

  16. Alkaline polyol pulping and enzymatic hydrolysis of softwood: effect of pulping severity and pulp properties on cellulase activity and overall sugar yield.

    PubMed

    Hundt, Martin; Schnitzlein, Klaus; Schnitzlein, Michael G

    2013-04-01

    The saccharification of softwood using alkaline polyol pulping (AlkaPolP) and enzymatic hydrolysis was investigated. It will be demonstrated that the AlkaPolP process yields high quality pulps which can easily be hydrolyzed by cellulases. Temperature (180-230°C) and duration (15-60 min) of the alkaline glycerol pulping, expressed as pulping severity R0, were varied to find optimum reaction conditions. The obtained pulps were characterized regarding their residual lignin content, kappa number and crystallinity index. Thus, the dependencies of the conversion during enzymatic hydrolysis on severity, pulp composition and pulp characteristics could be observed. In further experiments it was investigated how the enzymatic hydrolysis is affected by pulp drying or by a reduction of enzyme loading. Up to 83% of the initial cellulose in wood and almost 97% of the cellulose in pulp were converted into glucose using cellulases from Trichoderma reesei and β-glucosidase from Aspergillus niger. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Non-ionic surfactants do not consistently improve the enzymatic hydrolysis of pure cellulose.

    PubMed

    Zhou, Yan; Chen, Hongmei; Qi, Feng; Zhao, Xuebing; Liu, Dehua

    2015-04-01

    Non-ionic surfactants have been frequently reported to improve the enzymatic hydrolysis of pretreated lignocellulosic biomass and pure cellulose. However, how the hydrolysis condition, substrate structure and cellulase formulation affect the beneficial action of surfactants has not been well elucidated. In this work, it was found that the enzymatic hydrolysis of pure cellulose was not consistently improved by surfactants. Contrarily, high surfactant concentration, e.g. 5 g/L, which greatly improved the hydrolysis of dilute acid pretreated substrates, actually showed notable inhibition to pure cellulose conversion in the late phase of hydrolysis. Under an optimal hydrolysis condition, the improvement by surfactant was limited, but under harsh conditions surfactant indeed could enhance cellulose conversion. It was proposed that non-ionic surfactants could interact with substrates and cellulases to impact the adsorption behaviors of cellulases. Therefore, the beneficial action of surfactants on pure cellulose hydrolysis is influenced by hydrolysis condition, cellulose structural features and cellulase formulation.

  18. Cellulose accessibility determines the rate of enzymatic hydrolysis of steam-pretreated spruce.

    PubMed

    Wiman, Magnus; Dienes, Dora; Hansen, Mads A T; van der Meulen, Torbjörn; Zacchi, Guido; Lidén, Gunnar

    2012-12-01

    Spruce chips steam-pretreated at various conditions, according to a central composite design, were used for investigating the influence of pretreatment conditions on enzymatic hydrolysis, accounting for the individual effects of pretreatment temperature (194-220 °C), time (3-11 min) and sulfur dioxide uptake (0.7-2.5%). The materials were analyzed for several surface characteristics, including IR absorption, enzyme adsorption capacity, total surface area, cellulosic surface area, and cellulosic pore sizes. This work showed a clear correlation between rate of enzymatic hydrolysis and specific surface area. Although the lignin content of the particle surface increased at higher pretreatment temperature and residence time, the initial rate of enzymatic hydrolysis increased. Enzyme adsorption measurements and staining methods revealed that the higher rate of hydrolysis of these materials was due to increased accessibility of the cellulose. An accessible cellulose fraction is thus more important than a low surface lignin content for the enzymatic hydrolysis of steam-pretreated spruce.

  19. Enzymatic lignocellulose hydrolysis: Improved cellulase productivity by insoluble solids recycling

    PubMed Central

    2013-01-01

    Background It is necessary to develop efficient methods to produce renewable fuels from lignocellulosic biomass. One of the main challenges to the industrialization of lignocellulose conversion processes is the large amount of cellulase enzymes used for the hydrolysis of cellulose. One method for decreasing the amount of enzyme used is to recycle the enzymes. In this study, the recycle of enzymes associated with the insoluble solid fraction after the enzymatic hydrolysis of cellulose was investigated for pretreated corn stover under a variety of recycling conditions. Results It was found that a significant amount of cellulase activity could be recovered by recycling the insoluble biomass fraction, and the enzyme dosage could be decreased by 30% to achieve the same glucose yields under the most favorable conditions. Enzyme productivity (g glucose produced/g enzyme applied) increased between 30 and 50% by the recycling, depending on the reaction conditions. While increasing the amount of solids recycled increased process performance, the methods applicability was limited by its positive correlation with increasing total solids concentrations, reaction volumes, and lignin content of the insoluble residue. However, increasing amounts of lignin rich residue during the recycle did not negatively impact glucose yields. Conclusions To take advantage of this effect, the amount of solids recycled should be maximized, based on a given processes ability to deal with higher solids concentrations and volumes. Recycling of enzymes by recycling the insoluble solids fraction was thus shown to be an effective method to decrease enzyme usage, and research should be continued for its industrial application. PMID:23336604

  20. Optimization of enzymatic hydrolysis and fermentation conditions for improved bioethanol production from potato peel residues.

    PubMed

    Ben Taher, Imen; Fickers, Patrick; Chniti, Sofien; Hassouna, Mnasser

    2016-12-20

    The aim of this work was the optimization of the enzyme hydrolysis of potato peel residues (PPR) for bioethanol production. The process included a pretreatment step followed by an enzyme hydrolysis using crude enzyme system composed of cellulase, amylase and hemicellulase, produced by a mixed culture of Aspergillus niger and Trichoderma reesei. Hydrothermal, alkali and acid pretreatments were considered with regards to the enhancement of enzyme hydrolysis of potato peel residues. The obtained results showed that hydrothermal pretreatment lead to a higher enzyme hydrolysis yield compared to both acid and alkali pretreatments. Enzyme hydrolysis was also optimized for parameters such as temperature, pH, substrate loading and surfactant loading using a response surface methodology. Under optimized conditions, 77 g L(-1) of reducing sugars were obtained. Yeast fermentation of the released reducing sugars led to an ethanol titer of 30 g L(-1) after supplementation of the culture medium with ammonium sulfate. Moreover, a comparative study between acid and enzyme hydrolysis of potato peel residues was investigated. Results showed that enzyme hydrolysis offers higher yield of bioethanol production than acid hydrolysis. These results highlight the potential of second generation bioethanol production from potato peel residues treated with onsite produced hydrolytic enzymes. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 2016.

  1. Enzymatic hydrolysis preparation of mono-O-lauroylsucrose via a mono-O-lauroylraffinose intermediate.

    PubMed

    Lu, Yuyun; Yan, Rian; Ma, Xiang; Wang, Yong; Sun, Yuankui; Luo, Zhongming

    2013-10-02

    1'-O-Lauroylsucrose and 6'-O-lauroylsucrose were formed through hydrolysis of the C-6″ galactose group of 1'-O-lauroylraffinose and 6'-O-lauroylraffinose, respectively, in the presence of α-galactosidase. The enzymatic hydrolysis of 1'-O-lauroylraffinose and 6'-O-lauroylraffinose is discussed in detail. Acetic acid-sodium acetate was chosen as the buffer solution of the enzymatic hydrolysis reaction. The optimum conditions for the enzymatic hydrolysis reaction were as follows: buffer solution, pH 3.8; enzymatic time, 48 h; and enzymatic temperature, 37 °C. Under the optimal process conditions, the efficiency of α-galactosidase was ca. 82.6%. The isomers were fully compared in solubility, hydrophile-lipophile balance (HLB) values, critical micelle concentration (CMC), and thermal stability. The results showed that all lauroylsucrose isomers have similar solubilities in polar solvent, HLB values, CMC values, and thermal stabilities.

  2. Effects of hardwood structural and chemical characteristics on enzymatic hydrolysis for biofuel production.

    PubMed

    Santos, Ricardo B; Lee, Jung Myoung; Jameel, Hasan; Chang, Hou-Min; Lucia, Lucian A

    2012-04-01

    This study investigated the influence of various hardwood characteristics on enzymatic hydrolysis. Important hardwood species, including three Eucalyptus species, were comprehensively characterized using quantitative (13)C NMR, image analysis and fiber quality analysis. Hydrolysis efficiency from all the hardwoods was correlated to the wood chemical composition and lignin characteristics. Among the key wood components that control enzymatic hydrolysis efficiency, lignin content, enzyme adsorption on substrate and, the ratio of syringyl/guaiacyl (S/G) of the pretreated feedstock were identified as the most important. No wood morphological feature was found to have a significant influence on enzymatic conversion of the pretreated samples. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. [Response surface method optimize of nano-silica solid dispersion technology assistant enzymatic hydrolysis preparation genistein].

    PubMed

    Jin, Xin; Zhang, Zhen-Hai; Zhu, Jing; Sun, E; Yu, Dan-Hong; Chen, Xiao-Yun; Liu, Qi-Yuan; Ning, Qing; Jia, Xiao-Bin

    2012-04-01

    This article reports that nano-silica solid dispersion technology was used to raise genistein efficiency through increasing the enzymatic hydrolysis rate. Firstly, genistin-nano-silica solid dispersion was prepared by solvent method. And differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) were used to verify the formation of solid dispersion, then enzymatic hydrolysis of solid dispersion was done by snailase to get genistein. With the conversion of genistein as criteria, single factor experiments were used to study the different factors affecting enzymatic hydrolysis of genistin and its solid dispersion. And then, response surface method was used to optimize of nano-silica solid dispersion technology assistant enzymatic hydrolysis. The optimum condition to get genistein through enzymatic hydrolysis of genistin-nano-silica solid dispersion was pH 7.1, temperature 52.2 degrees C, enzyme concentration 5.0 mg x mL(-1) and reaction time 7 h. Under this condition, the conversion of genistein was (93.47 +/- 2.40)%. Comparing with that without forming the genistin-nano-silica solid dispersion, the conversion increased 2.62 fold. At the same time, the product of hydrolysis was purified to get pure genistein. The method of enzymatic hydrolysis of genistin-nano-silica solid dispersion by snailase to obtain genistein is simple, efficiency and suitable for the modern scale production.

  4. Impacts of microalgae pre-treatments for improved anaerobic digestion: thermal treatment, thermal hydrolysis, ultrasound and enzymatic hydrolysis.

    PubMed

    Ometto, Francesco; Quiroga, Gerardo; Pšenička, Pavel; Whitton, Rachel; Jefferson, Bruce; Villa, Raffaella

    2014-11-15

    Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This work investigated the effect of four pre-treatments on three microalgae species, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. The analysis of the composition of the soluble COD released and of the TEM images of the cells showed two main degradation actions associated with the processes: (1) cell wall damage with the release of intracellular AOM (thermal, thermal hydrolysis and ultrasound) and (2) degradation of the cell wall constituents with the release of intracellular AOM and the solubilisation of the cell wall biopolymers (enzymatic hydrolysis). As a result of this, enzymatic hydrolysis showed the greatest biogas yield increments (>270%) followed by thermal hydrolysis (60-100%) and ultrasounds (30-60%).

  5. Numerical prediction of kinetic model for enzymatic hydrolysis of cellulose using DAE-QMOM approach

    NASA Astrophysics Data System (ADS)

    Jamil, N. M.; Wang, Q.

    2016-06-01

    Bioethanol production from lignocellulosic biomass consists of three fundamental processes; pre-treatment, enzymatic hydrolysis, and fermentation. In enzymatic hydrolysis phase, the enzymes break the cellulose chains into sugar in the form of cellobiose or glucose. A currently proposed kinetic model for enzymatic hydrolysis of cellulose that uses population balance equation (PBE) mechanism was studied. The complexity of the model due to integrodifferential equations makes it difficult to find the analytical solution. Therefore, we solved the full model of PBE numerically by using DAE-QMOM approach. The computation was carried out using MATLAB software. The numerical results were compared to the asymptotic solution developed in the author's previous paper and the results of Griggs et al. Besides confirming the findings were consistent with those references, some significant characteristics were also captured. The PBE model for enzymatic hydrolysis process can be solved using DAE-QMOM method. Also, an improved understanding of the physical insights of the model was achieved.

  6. Quantification of bound and free enzymes during enzymatic hydrolysis and their reactivities on cellulose and lignocellulose.

    PubMed

    Yu, Zhiying; Jameel, Hasan; Chang, Hou-min; Philips, Richard; Park, Sunkyu

    2013-11-01

    Enzymatic hydrolysis of insoluble biomass is a surface reaction. Part of the enzyme adsorb on the surface of biomass, whereas the others stay in the liquid phase. In this study, three substrates (Avicel cellulose, bleached hardwood pulp, and green-liquor pretreated hardwood pulp) were used to study the reactivity of bound and free enzyme. In a continuous enzymatic hydrolysis, 35-65% initially added enzymes became bound enzymes, which were primarily responsible for enzymatic hydrolysis. The contribution from free enzymes became insignificant after a certain period of reaction time. SDS-PAGE analysis showed that CBH I was significantly decreased in the free enzyme, which might be the reason for the low digestibility of free enzymes due to the loss of synergistic effect. When Tween 80 was added during enzymatic hydrolysis, the digestibility of free enzyme on Avicel was greatly enhanced. However, the benefit of surfactant was not noticeable for lignocellulosic pulps, comparing to Avicel.

  7. Combined steam pretreatment and enzymatic hydrolysis of starch-free wheat fibers.

    PubMed

    Palmarola-Adrados, Beatriz; Galbe, Mats; Zacchi, Guido

    2004-01-01

    Steam treatment of an industrial process stream, denoted starch-free wheat fiber, was investigated to improve the formation of monomeric sugars in subsequent enzymatic hydrolysis for further bioconversion into ethanol. The solid fraction in the process stream, derived from a combined starch and ethanol factory, was rich in arabinose (21.1%), xylose (30.1%), and glucose (18.6%), in the form of polysaccharides. Various conditions of steam pretreatment (170-220 degrees C for 5-30 min) were evaluated, and their effect was assessed by enzymatic hydrolysis with 2 g of Celluclast + Ultraflo mixture/100 g of starch-free fiber (SFF) slurry at 5% dry matter (DM). The highest overall sugar yield for the combined steam pretreatment and enzymatic hydrolysis, 52 g/100 g of DM of SFF, corresponding to 74% of the theoretical, was achieved with pretreatment at 190 degrees C for 10 min followed by enzymatic hydrolysis.

  8. Mechanism of the positive effect of poly(ethylene glycol) addition in enzymatic hydrolysis of steam pretreated lignocelluloses.

    PubMed

    Sipos, Bálint; Szilágyi, Mátyás; Sebestyén, Zoltán; Perazzini, Raffaella; Dienes, Dóra; Jakab, Emma; Crestini, Claudia; Réczey, Kati

    2011-11-01

    The efficiency of enzymatic hydrolysis of lignocellulses can be increased by addition of surfactants and polymers, such as poly(ethylene glycol) (PEG). The effect of PEG addition on the cellulase adsorption was tested on various steam pretreated lignocellulose substrates (spruce, willow, hemp, corn stover, wheat straw, sweet sorghum bagasse). A positive effect of PEG addition was observed, as protein adsorption has decreased and free enzyme activities (FP, β-glucosidase) have increased due to the additive. However, the degree of enhancement differed among the substrates, being highest on steam pretreated spruce. Results of lignin analysis (pyrolysis-GC/MS, (31)P NMR) suggest that the effect of PEG addition is in connection with the amount of unsubstituted phenolic hydroxyl groups of lignin in the substrate. Adsorption experiments using two commercial enzyme preparations, Celluclast 1.5L (Trichoderma reesei cellulase) and Novozym 188 (Aspergillus niger β-glucosidase) suggested that enzyme origins affected on the adsorptivity of β-glucosidases. Copyright © 2011 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  9. Fuzzy logic feedback control for fed-batch enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Tai, Chao; Voltan, Diego S; Keshwani, Deepak R; Meyer, George E; Kuhar, Pankaj S

    2016-06-01

    A fuzzy logic feedback control system was developed for process monitoring and feeding control in fed-batch enzymatic hydrolysis of a lignocellulosic biomass, dilute acid-pretreated corn stover. Digested glucose from hydrolysis reaction was assigned as input while doser feeding time and speed of pretreated biomass were responses from fuzzy logic control system. Membership functions for these three variables and rule-base were created based on batch hydrolysis data. The system response was first tested in LabVIEW environment then the performance was evaluated through real-time hydrolysis reaction. The feeding operations were determined timely by fuzzy logic control system and efficient responses were shown to plateau phases during hydrolysis. Feeding of proper amount of cellulose and maintaining solids content was well balanced. Fuzzy logic proved to be a robust and effective online feeding control tool for fed-batch enzymatic hydrolysis.

  10. Three-stage enzymatic hydrolysis of steam-exploded corn stover at high substrate concentration.

    PubMed

    Yang, Jing; Zhang, Xiaoping; Yong, Qiang; Yu, Shiyuan

    2011-04-01

    The feasibility of three-stage hydrolysis of steam-exploded corn stover at high-substrate concentration was investigated. When substrate concentration was 30% and enzyme loading was 15-30 FPU/g cellulose, three-stage (9+9+12 h) hydrolysis could reach a hydrolysis yield of 59.9-81.4% in 30 h. Compared with one-stage hydrolysis for 72 h, an increase of 34-37% in hydrolysis yield could be achieved. When steam-exploded corn stover was used as the substrate for enzyme synthesis and hydrolysis was conducted at a substrate concentration of 25% with an enzyme loading of 20 FPU/g cellulose, a hydrolysis yield of 85.1% was obtained, 19% higher than that the commercial cellulase could reach under the same conditions. The removal of end products was suggested to improve the adsorption of cellulase on the substrate and enhance the productivity of enzymatic hydrolysis.

  11. Low Intensity Uniform Ultrasound Accelerates Enzymatic Hydrolysis of Cellulose Plant Matter

    USDA-ARS?s Scientific Manuscript database

    The work reported here is based on acceleration of enzymatic hydrolysis of plant biomass substrate by introduction of low intensity, uniform ultrasound field into a reaction chamber (bio-reactor). This method may serve as an improvement of rates in the hydrolysis of cellulosic materials to sugars, ...

  12. Use of an algal hydrolysate to improve enzymatic hydrolysis of anaerobically digested fiber

    USDA-ARS?s Scientific Manuscript database

    This study investigated the use of acid hydrolyzed algae to enhance the enzymatic hydrolysis of cellulosic biomass. We first characterized wastewater-grown algal samples and determined the optimal conditions (acid concentration, reaction temperature, and reaction time) for algal hydrolysis using di...

  13. Bioethanol production: an integrated process of low substrate loading hydrolysis-high sugars liquid fermentation and solid state fermentation of enzymatic hydrolysis residue.

    PubMed

    Chu, Qiulu; Li, Xin; Ma, Bin; Xu, Yong; Ouyang, Jia; Zhu, Junjun; Yu, Shiyuan; Yong, Qiang

    2012-11-01

    An integrated process of enzymatic hydrolysis and fermentation was investigated for high ethanol production. The combination of enzymatic hydrolysis at low substrate loading, liquid fermentation of high sugars concentration and solid state fermentation of enzymatic hydrolysis residue was beneficial for conversion of steam explosion pretreated corn stover to ethanol. The results suggested that low substrate loading hydrolysis caused a high enzymatic hydrolysis yield; the liquid fermentation of about 200g/L glucose by Saccharomyces cerevisiae provided a high ethanol concentration which could significantly decrease cost of the subsequent ethanol distillation. A solid state fermentation of enzymatic hydrolysis residue was combined, which was available to enhance ethanol production and cellulose-to-ethanol conversion. The results of solid state fermentation demonstrated that the solid state fermentation process accompanied by simultaneous saccharification and fermentation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Isolation and characterization of nicotiflorin obtained by enzymatic hydrolysis of two precursors in tea seed extract.

    PubMed

    Lee, Hyang-Bok; Kim, Eun-Ki; Park, Sang-Jae; Bang, Sang-Gu; Kim, Tae Gil; Chung, Dae-Won

    2010-04-28

    Two flavonol triglycosides, camelliaside A (CamA) and camelliaside B (CamB), of tea seed extract (TSE) were subjected to enzymatic hydrolysis. Among five kinds of glycosidases investigated, beta-galactosidase (Gal) induced selective hydrolysis of CamA. On the other hand, pectinase (Pec) and cellulase (Cel) induced hydrolysis of CamB. For Gal and Pec, only kaempferol diglycoside (nicotiflorin, NF) was produced; on the other hand, significant amounts of kaempferol monoglycoside (astragalin, AS) and kaempferol (KR) were also detected for Cel. The combination of the use of Gal and Pec in the enzymatic hydrolysis of TSE afforded NF with high specificity. Crude NF with 22% purity was recovered from the enzymatic reaction mixture by extraction with organic solvent, and pure NF with >95% purity was obtained by crystallized in water. The chemical structure of NF was confirmed by (1)H and (13)C NMR analyses.

  15. Improving enzymatic hydrolysis of industrial hemp ( Cannabis sativa L.) by electron beam irradiation

    NASA Astrophysics Data System (ADS)

    Shin, Soo-Jeong; Sung, Yong Joo

    2008-09-01

    The electron beam irradiation was applied as a pretreatment of the enzymatic hydrolysis of hemp biomass with doses of 150, 300 and 450 kGy. The higher irradiation dose resulted in the more extraction with hot-water extraction or 1% sodium hydroxide solution extraction. The higher solubility of the treated sample was originated from the chains scission during irradiation, which was indirectly demonstrated by the increase of carbonyl groups as shown in diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra. The changes in the micro-structure of hemp resulted in the better response to enzymatic hydrolysis with commercial cellulases (Celluclast 1.5L and Novozym 342). The improvement in enzymatic hydrolysis by the irradiation was more evident in the hydrolysis of the xylan than in that of the cellulose.

  16. Enzyme feeding strategies for better fed-batch enzymatic hydrolysis of empty fruit bunch.

    PubMed

    Sugiharto, Yohanes Eko Chandra; Harimawan, Ardiyan; Kresnowati, Made Tri Ari Penia; Purwadi, Ronny; Mariyana, Rina; Andry; Fitriana, Hana Nur; Hosen, Hauna Fathmadinda

    2016-05-01

    Lignin inhibitory becomes a major obstacle for enzymatic hydrolysis of empty fruit bunch conducted in high solid loading. Since current technology required high enzyme loading, surfactant application could not effectively used since it is only efficient in low enzyme loading. In addition, it will increase final operation cost. Hence, another method namely "proportional enzyme feeding" was investigated in this paper. In this method, enzyme was added to reactor proportionally to substrate addition, different from conventional method ("whole enzyme feeding") where whole enzyme was added prior to hydrolysis process started. Proportional enzyme feeding could increase enzymatic digestibility and glucose concentration up to 26% and 12% respectively, compared to whole enzyme feeding for hydrolysis duration more than 40h. If enzymatic hydrolysis was run less than 40h (25% solid loading), whole enzyme feeding is preferable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effects of pretreatment factors on fermentable sugar production and enzymatic hydrolysis of mixed hardwood.

    PubMed

    Lim, Woo-Seok; Lee, Jae-Won

    2013-02-01

    The aim of this study was to investigate the effects of different acid catalysts and pretreatment factors on the hydrolysis of biomass compounds over a range of thermochemical pretreatments; maleic, oxalic, and sulfuric acids were each used under different pretreatment conditions. The most influential factor for fermentable sugar production in the dicarboxylic acid-pretreated mixed hardwood was pH. Reaction time was the next significant factor followed by reaction temperature. However, fermentable sugar production was more dependent on reaction temperature than time during sulfuric acid pretreatment, whereas the effect of acid concentration was considerably lower. Maleic acid pretreatment was very effective for attaining high glucose yields after enzymatic hydrolysis. The highest enzymatic hydrolysis yield was found following maleic acid pretreatment, which reached 95.56%. The trend in enzymatic hydrolysis yields that were detected concomitantly with pretreatment condition or type of acid catalyst was closely related to xylose production in the hydrolysate.

  18. Intensification of enzymatic hydrolysis of waste newspaper using ultrasound for fermentable sugar production.

    PubMed

    Subhedar, Preeti B; Babu, Narmadha R; Gogate, Parag R

    2015-01-01

    An effective conversion of lignocellulose into fermentable sugars is a key step in producing bioethanol in an eco-friendly and cost effective manner. In this study, the effect of ultrasound on enzymatic hydrolysis of newspaper, a potential feedstock for bioethanol production due to its high cellulosic content, was investigated. The effect of substrate loading, enzyme loading, temperature, ultrasonic power and duty cycle on the hydrolysis has been studied. Optimum conditions for conventional enzymatic hydrolysis were substrate loading of 5% (w/v), enzyme loading of 0.14% (w/v), temperature of 323K, and under these conditions and 72h of hydrolysis, reducing sugar yield of 11.569g/L was obtained. In case of ultrasound-assisted enzymatic hydrolysis approach, optimum conditions obtained were substrate loading of 3% (w/v), enzyme loading of 0.8% (w/v), sonication power of 60W, duty cycle of 70%, hydrolysis time of 6.5h and the reducing sugar yield obtained under these conditions was 27.6g/L. Approximately 2.4 times increase in the release of reducing sugar concentration was obtained by the ultrasound-assisted enzymatic hydrolysis approach. Results indicate that there is a synergistic effect obtained from the combination of ultrasound and enzymes which lowers the diffusion-limiting barrier to enzyme/substrate binding and results in an increase in reaction rate. The experimental data were also fitted in a simple three parameter kinetic model.

  19. Hydrogel coated monoliths for enzymatic hydrolysis of penicillin G

    PubMed Central

    Smeltink, M. W.; Straathof, A. J. J.; Paasman, M. A.; van de Sandt, E. J. A. X.; Kapteijn, F.; Moulijn, J. A.

    2008-01-01

    The objective of this work was to develop a hydrogel-coated monolith for the entrapment of penicillin G acylase (E. coli, PGA). After screening of different hydrogels, chitosan was chosen as the carrier material for the preparation of monolithic biocatalysts. This protocol leads to active immobilized biocatalysts for the enzymatic hydrolysis of penicillin G (PenG). The monolithic biocatalyst was tested in a monolith loop reactor (MLR) and compared with conventional reactor systems using free PGA, and a commercially available immobilized PGA. The optimal immobilization protocol was found to be 5 g l−1 PGA, 1% chitosan, 1.1% glutaraldehyde and pH 7. Final PGA loading on glass plates was 29 mg ml−1 gel. For 400 cpsi monoliths, the final PGA loading on functionalized monoliths was 36 mg ml−1 gel. The observed volumetric reaction rate in the MLR was 0.79 mol s−1 m−3monolith. Apart from an initial drop in activity due to wash out of PGA at higher ionic strength, no decrease in activity was observed after five subsequent activity test runs. The storage stability of the biocatalysts is at least a month without loss of activity. Although the monolithic biocatalyst as used in the MLR is still outperformed by the current industrial catalyst (immobilized preparation of PGA, 4.5 mol s−1 m−3catalyst), the rate per gel volume is slightly higher for monolithic catalysts. Good activity and improved mechanical strength make the monolithic bioreactor an interesting alternative that deserves further investigation for this application. Although moderate internal diffusion limitations have been observed inside the gel beads and in the gel layer on the monolith channel, this is not the main reason for the large differences in reactor performance that were observed. The pH drop over the reactor as a result of the chosen method for pH control results in a decreased performance of both the MLR and the packed bed reactor compared to the batch system. A different

  20. Bioabatement with hemicellulase supplementation to reduce enzymatic hydrolysis inhibitors

    USDA-ARS?s Scientific Manuscript database

    Removal of inhibitory compounds by bioabatement, combined with xylan hydrolysis, enables effective cellulose hydrolysis of pretreated corn stover, for fermentation of the sugars to fuel ethanol or other products. The fungus Coniochaeta ligniaria NRRL30616 eliminates most enzyme and fermentation inhi...

  1. The pattern of cell wall deterioration in lignocellulose fibers throughout enzymatic cellulose hydrolysis.

    PubMed

    Li, Xinping; Clarke, Kimberley; Li, Kecheng; Chen, Aicheng

    2012-01-01

    Cell wall deterioration throughout enzymatic hydrolysis of cellulosic biomass is greatly affected by the chemical composition and the ultrastructure of the fiber cell wall. The resulting pattern of cell wall deterioration will reveal information on cellulose activity throughout enzymatic hydrolysis. This study investigates the progression and morphological changes in lignocellulose fibers throughout enzymatic hydrolysis, using (transmission electron microscopy) TEM and field emission scanning electron microscopy (FE-SEM). Softwood thermo-mechanical pulp (STMP) and softwood bleached kraft pulp (SBKP), lignocellulose substrates containing almost all the original fiber composition, and with lignin and some hemicellulose removed, respectively, was compared for morphology changes throughout hydrolysis. The difference of conversion between STMP and SBKP after 48 h of enzymatic hydrolysis is 11 and 88%, respectively. TEM images revealed an even fiber cell wall cross section density, with uneven middle lamella coverage in STMP fibers. SKBP fibers exhibited some spaces between cell wall and lamella layers due to the removal of lignin and some hemicellulose. After 1 h hydrolysis in SBKP fibers, there were more changes in the fiber cross-sectional area than after 10 h hydrolysis in STMP fibers. Cell wall degradation was uneven, and originated in accessible cellulose throughout the fiber cell wall. FE-SEM images illustrated more morphology changes in SBKP fibers than STMP fibers. Enzymatic action of STMP fiber resulted in a smoother fiber surface, along with fiber peeling and the formation of ribbon-disjunction layers. SBKP fibers exhibited structural changes such as fiber erosion, fiber cutting, and fiber splitting throughout enzymatic hydrolysis.

  2. Inert and oxidative subcritical water hydrolysis of insoluble egg yolk granular protein, functional properties, and comparison to enzymatic hydrolysis.

    PubMed

    Marcet, Ismael; Álvarez, Carlos; Paredes, Benjamín; Díaz, Mario

    2014-08-13

    The use of enzymes to recover soluble peptides with functional properties from insoluble proteins could prove to be very expensive, implying high reaction times and low yields. In this study, the insoluble granular protein, previously delipidated, was hydrolyzed using enzymes (trypsin) as a comparison to the proposed alternative method: subcritical water hydrolysis (SWH) using both nitrogen and oxygen streams. The result of the hydrolysis was characterized in terms of the yield and peptide size distribution as well as different functional properties. The SWH of the delipidated granules resulted in a higher recovery yield than that obtained by enzymatic hydrolysis in half of the time. The foaming capacity of the peptides obtained by SWH was higher than that obtained by trypsin hydrolysis, although the foam stability was lower. Slight differences were detected between these peptides in terms of their emulsifying properties.

  3. Comparison of enzymatic and acid hydrolysis of bound flavor compounds in model system and grapes.

    PubMed

    Dziadas, Mariusz; Jeleń, Henryk H

    2016-01-01

    Four synthesized terpenyl-ß-D-glycopyranosides (geranyl, neryl, citronellyl, myrtenyl) were subjected to enzymatic (AR 2000, pH 5.5) and acid (citric buffer, pH 2.5) hydrolysis. Decrease of glycosides was measured by HPLC and the volatiles released--by comprehensive gas chromatography-mass spectrometry (GC × GC-ToF-MS). Enzymatic hydrolysis performed for 21 h yielded 100% degree of hydrolysis for all glycosides but citronellyl (97%). Degree of acid hydrolysis was highly dependent on type of aglycone and the conditions. The highest degree was achieved for geraniol, followed by citronellol and nerol. Myrtenylo-ß-D-glycopyranoside was the most resistant glycoside to hydrolysis. Acid hydrolysis degree was also related to temperature/time combination, the highest being for 100 °C and 2 h. In a result of enzymatic hydrolysis 85-91% of total peak areas was terpene aglycone, whereas for acid hydrolysis the area of released terpene aglycone did not exceed 1.3% of total peak area indicating almost complete decomposition/transformation of terpenyl aglycone.

  4. Enzymatic hydrolysis of pretreated waste paper--source of raw material for production of liquid biofuels.

    PubMed

    Brummer, Vladimir; Jurena, Tomas; Hlavacek, Viliam; Omelkova, Jirina; Bebar, Ladislav; Gabriel, Petr; Stehlik, Petr

    2014-01-01

    Enzymatic hydrolysis of waste paper is becoming a perspective way to obtain raw material for production of liquid biofuels. Reducing sugars solutions that arise from the process of saccharification are a precursors for following or simultaneous fermentation to ethanol. Different types of waste paper were evaluated, in terms of composition and usability, in order to select the appropriate type of the waste paper for the enzymatic hydrolysis process. Novozymes® enzymes NS50013 and NS50010 were used in a laboratory scale trials. Technological conditions, which seem to be the most suitable for hydrolysis after testing on cellulose pulp and filter paper, were applied to hydrolysis of widely available waste papers - offset paper, cardboard, recycled paper in two qualities, matte MYsol offset paper and for comparison again on model materials. The highest yields were achieved for the cardboard, which was further tested using various pretreatment combinations in purpose of increasing the hydrolysis yields.

  5. Combined subcritical water and enzymatic hydrolysis for reducing sugar production from coconut husk

    NASA Astrophysics Data System (ADS)

    Muharja, Maktum; Junianti, Fitri; Nurtono, Tantular; Widjaja, Arief

    2017-05-01

    Coconut husk wastes are abundantly available in Indonesia. It has a potential to be used into alternative renewable energy sources such as hydrogen using enzymatic hydrolysis followed by a fermentation process. Unfortunately, enzymatic hydrolysis is hampered by the complex structure of lignocellulose, so the cellulose component is hard to degrade. In this study, Combined Subcritical Water (SCW) and enzymatic hydrolysis are applied to enhance fermentable, thereby reducing production of sugar from coconut husk. There were two steps in this study, the first step was coconut husk pretreated by SCW in batch reactor at 80 bar and 150-200°C for 60 minutes reaction time. Secondly, solid fraction from the results of SCW was hydrolyzed using the mixture of pure cellulose and xylanase enzymes. Analysis was conducted on untreated and SCW-treated by gravimetric assay, liquid fraction after SCW and solid fraction after enzymatic hydrolysis using DNS assay. The maximum yield of reducing sugar (including xylose, arabinose glucose, galactose, mannose) was 1.254 gr per 6 gr raw material, representing 53.95% of total sugar in coconut husk biomass which was obtained at 150°C 80 bar for 60 minutes reaction time of SCW-treated and 6 hour of enzymatic hydrolysis using mixture of pure cellulose and xylanase enzymes (18.6 U /gram of coconut husk).

  6. Continuous enzymatic hydrolysis of lignocellulosic biomass with simultaneous detoxification and enzyme recovery.

    PubMed

    Gurram, Raghu N; Menkhaus, Todd J

    2014-07-01

    Recovering hydrolysis enzymes and/or alternative enzyme addition strategies are two potential mechanisms for reducing the cost during the biochemical conversion of lignocellulosic materials into renewable biofuels and biochemicals. Here, we show that enzymatic hydrolysis of acid-pretreated pine wood with continuous and/or fed-batch enzyme addition improved sugar conversion efficiencies by over sixfold. In addition, specific activity of the hydrolysis enzymes (cellulases, hemicellulases, etc.) increased as a result of continuously washing the residual solids with removal of glucose (avoiding the end product inhibition) and other enzymatic inhibitory compounds (e.g., furfural, hydroxymethyl furfural, organic acids, and phenolics). As part of the continuous hydrolysis, anion exchange resin was tested for its dual application of simultaneous enzyme recovery and removal of potential enzymatic and fermentation inhibitors. Amberlite IRA-96 showed favorable adsorption profiles of inhibitors, especially furfural, hydroxymethyl furfural, and acetic acid with low affinity toward sugars. Affinity of hydrolysis enzymes to adsorb onto the resin allowed for up to 92 % of the enzymatic activity to be recovered using a relatively low-molar NaCl wash solution. Integration of an ion exchange column with enzyme recovery into the proposed fed-batch hydrolysis process can improve the overall biorefinery efficiency and can greatly reduce the production costs of lignocellulosic biorenewable products.

  7. Optimization of dilute acid pretreatment of water hyacinth biomass for enzymatic hydrolysis and ethanol production

    PubMed Central

    Idrees, Muhammad; Adnan, Ahmad; Sheikh, Shahzad; Qureshic, Fahim Ashraf

    2013-01-01

    The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature (oC), time (hr) and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables with P < 0.05. High F and R2 values and low P-value for hydrolysis yield indicated the model predictability. The pretreated biomass producing 39.96 g/l, 39.86 g/l and 37.9 g/l of reducing sugars during enzymatic hydrolysis with yield 79.93, 78.71 and 75.9 % from PA, MA and SA treated respectively. The order of catalytic effectiveness for hydrolysis yield was found to be phosphoric acid > maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker's yeast (Sacchromyces cerveasiae). PMID:26417215

  8. Optimization of dilute acid pretreatment of water hyacinth biomass for enzymatic hydrolysis and ethanol production.

    PubMed

    Idrees, Muhammad; Adnan, Ahmad; Sheikh, Shahzad; Qureshic, Fahim Ashraf

    2013-01-01

    The present study was conducted for the optimization of pretreatment process that was used for enzymatic hydrolysis of lignocellulosic biomass (Water Hyacinth, WH), which is a renewable resource for the production of bioethanol with decentralized availability. Response surface methodology has been employed for the optimization of temperature ((o)C), time (hr) and different concentrations of maleic acid (MA), sulfuric acid (SA) and phosphoric acid (PA) that seemed to be significant variables with P < 0.05. High F and R (2) values and low P-value for hydrolysis yield indicated the model predictability. The pretreated biomass producing 39.96 g/l, 39.86 g/l and 37.9 g/l of reducing sugars during enzymatic hydrolysis with yield 79.93, 78.71 and 75.9 % from PA, MA and SA treated respectively. The order of catalytic effectiveness for hydrolysis yield was found to be phosphoric acid > maleic acid > sulfuric acid. Mixture of sugars was obtained during dilute acid pretreatment with glucose being the most prominent sugar while pure glucose was obtained during enzymatic hydrolysis. The resulting sugars, obtained during enzymatic hydrolysis were finally fermented to ethanol, with yield 0.484 g/g of reducing sugars which is 95 % of theoretical yield (0.51 g/g glucose) by using commercial baker's yeast (Sacchromyces cerveasiae).

  9. Enhancing fermentable sugar yield from cassava pulp for bioethanol production: microwave-coupled enzymatic hydrolysis approach.

    PubMed

    Sudha, A; Sivakumar, V; Sangeetha, V; Devi, K S Priyenka

    2015-08-01

    Cassava pulp, a potential biological feedstock for ethanol production has been subjected to microwave-assisted alkali pretreatment and microwave-coupled enzymatic hydrolysis. Microwave pretreatment may be a good alternative as it can reduce the pretreatment time and improve the enzymatic activity during hydrolysis. Liquid to solid ratio for the pretreatment of cassava pulp was found to be 20:1. Cassava pulp was pretreated at various NaOH concentration, microwave temperature and gave maximum yield of reducing sugar with 1.5% NaOH at 90 °C in 30 min than conventional alkali pretreatment after enzymatic hydrolysis. The subsequent enzymatic saccharification of pretreated cassava pulp using α amylase dosage of 400 IU at microwave temperature of 90 °C resulted in highest reducing sugar yield of 723 mg/g pulp. Microwave-assisted alkali pretreatment improved the enzymatic saccharification of cassava pulp by increasing its accessibility to hydrolytic enzymes. Microwave-assisted alkali pretreatment and microwave-coupled enzymatic hydrolysis are found to be efficient for improving the yield of reducing sugar.

  10. Study of Enzymatic Hydrolysis of Fructans from Agave salmiana Characterization and Kinetic Assessment

    PubMed Central

    Michel-Cuello, Christian; Ortiz-Cerda, Imelda; Moreno-Vilet, Lorena; Grajales-Lagunes, Alicia; Moscosa-Santillán, Mario; Bonnin, Johanne; González-Chávez, Marco Martín; Ruiz-Cabrera, Miguel

    2012-01-01

    Fructans were extracted from Agave salmiana juice, characterized and subjected to hydrolysis process using a commercial inulinase preparation acting freely. To compare the performance of the enzymatic preparation, a batch of experiments were also conducted with chicory inulin (reference). Hydrolysis was performed for 6 h at two temperatures (50, 60°C) and two substrate concentrations (40, 60 mg/ml). Hydrolysis process was monitored by measuring the sugars released and residual substrate by HPLC. A mathematical model which describes the kinetics of substrate degradation as well as fructose production was proposed to analyze the hydrolysis assessment. It was found that kinetics were significantly influenced by temperature, substrate concentration, and type of substrate (P < 0.01). The extent of substrate hydrolysis varied from 82 to 99%. Hydrolysis product was mainly constituted of fructose, obtaining from 77 to 96.4% of total reducing sugars. PMID:22629216

  11. Study of enzymatic hydrolysis of fructans from Agave salmiana characterization and kinetic assessment.

    PubMed

    Michel-Cuello, Christian; Ortiz-Cerda, Imelda; Moreno-Vilet, Lorena; Grajales-Lagunes, Alicia; Moscosa-Santillán, Mario; Bonnin, Johanne; González-Chávez, Marco Martín; Ruiz-Cabrera, Miguel

    2012-01-01

    Fructans were extracted from Agave salmiana juice, characterized and subjected to hydrolysis process using a commercial inulinase preparation acting freely. To compare the performance of the enzymatic preparation, a batch of experiments were also conducted with chicory inulin (reference). Hydrolysis was performed for 6 h at two temperatures (50, 60 °C) and two substrate concentrations (40, 60 mg/ml). Hydrolysis process was monitored by measuring the sugars released and residual substrate by HPLC. A mathematical model which describes the kinetics of substrate degradation as well as fructose production was proposed to analyze the hydrolysis assessment. It was found that kinetics were significantly influenced by temperature, substrate concentration, and type of substrate (P < 0.01). The extent of substrate hydrolysis varied from 82 to 99%. Hydrolysis product was mainly constituted of fructose, obtaining from 77 to 96.4% of total reducing sugars.

  12. Screw extrude steam explosion: a promising pretreatment of corn stover to enhance enzymatic hydrolysis.

    PubMed

    Chen, Jingwen; Zhang, Wengui; Zhang, Hongman; Zhang, Qiuxiang; Huang, He

    2014-06-01

    A screw extrude steam explosion (SESE) apparatus was designed and introduced to pretreat corn stover continuously for its following enzymatic hydrolysis. SESE parameters temperature (100, 120, 150°C) and residence time (1, 2, 3min) were investigated. The enzymatic hydrolysis of corn stover pretreated by SESE and steam explosion (SE) process was carried out and analyzed systematically. A serial of analysis methods were established, and the corn stover before/after the pretreatment were characterized by scanning electron microscope (SEM), X-ray Diffraction (XRD) and Thermal Gravity/Derivative Thermal Gravity Analysis (TG/DTG). After treated by SESE pretreatment at the optimum condition (150°C, 2min), the pretreated corn stover exhibited highest enzymatic hydrolysis yield (89%), and rare fermentation inhibitors formed. Characterization results indicated that the highest yield could be attributed to the effective removal of lignin/hemicellulose and destruction of cellulose structure by SESE pretreatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Unraveling the effects of laccase treatment on enzymatic hydrolysis of steam-exploded wheat straw.

    PubMed

    Oliva-Taravilla, Alfredo; Moreno, Antonio D; Demuez, Marie; Ibarra, David; Tomás-Pejó, Elia; González-Fernández, Cristina; Ballesteros, Mercedes

    2015-01-01

    Laccase enzymes are promising detoxifying agents during lignocellulosic bioethanol production from wheat straw. However, they affect the enzymatic hydrolysis of this material by lowering the glucose recovery yields. This work aimed at explaining the negative effects of laccase on enzymatic hydrolysis. Relative glucose recovery in presence of laccase (10IU/g substrate) with model cellulosic substrate (Sigmacell) at 10% (w/v) was almost 10% points lower (P<0.01) than in the absence of laccase. This fact could be due to an increase in the competition of cellulose binding sites between the enzymes and a slight inhibition of β-glucosidase activity. However, enzymatic hydrolysis and infrared spectra of laccase-treated and untreated wheat straw filtered pretreated residue (WS-FPR), revealed that a grafting process of phenoxy radicals onto the lignin fiber could be the cause of diminished accessibility of cellulases to cellulose in pretreated wheat straw. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Sterol Glycosides from Foods Rich in Δ(7)-Sterols.

    PubMed

    Münger, Linda H; Jutzi, Sabrina; Lampi, Anna-Maija; Nyström, Laura

    2015-08-01

    In this study, we present the difference in sterol composition of extracted steryl glycosides (SG) hydrolyzed by either enzymatic or acid hydrolysis. SG were analyzed from foods belonging to the plant families Cucurbitaceae (melon and pumpkin seeds) and Amaranthaceae (amaranth and beetroot), both of which are dominated by Δ(7)-sterols. Released sterols were quantified by gas chromatography with a flame ionization detector (GC-FID) and identified using gas chromatography/mass spectrometry (GC-MS). All Δ(7)-sterols identified (Δ(7)-stigmastenyl, spinasteryl, Δ(7)-campesteryl, Δ(7)-avenasteryl, poriferasta-7,25-dienyl and poriferasta-7,22,25-trienyl glucoside) underwent isomerization under acidic conditions and high temperature. Sterols with an ethylidene or methylidene side chain were found to form multiple artifacts. The artifact sterols coeluted with residues of incompletely isomerized Δ(7)-sterols, or Δ(5)-sterols if present, and could be identified as Δ(8(14))-sterols on the basis of relative retention time, and their MS spectra as trimethylsilyl (TMS) and acetate derivatives. For instance, SG from melon were composed of 66% Δ(7)-stigmastenol when enzymatic hydrolysis was performed, whereas with acid hydrolysis only 8% of Δ(7)-stigmastenol was determined. The artifact of Δ(7)-stigmastenol coeluted with residual non-isomerized spinasterol, demonstrating the high risk of misinterpretation of compositional data obtained after acid hydrolysis. Therefore, the accurate composition of SG from foods containing sterols with a double bond at C-7 can only be obtained by enzymatic hydrolysis or by direct analysis of the intact SG.

  15. Oxidative processes during enzymatic hydrolysis of cod protein and their influence on antioxidant and immunomodulating ability.

    PubMed

    Halldorsdottir, Sigrun M; Sveinsdottir, Holmfridur; Freysdottir, Jona; Kristinsson, Hordur G

    2014-01-01

    Fish protein hydrolysates (FPH) have many desirable properties, however heating and shifts in pH can cause oxidation during enzymatic hydrolysis. The objective was to investigate oxidative processes during enzymatic hydrolysis of fish protein and the impact of oxidation on the antioxidant and immunomodulating ability of FPH. Protease P "Amano" 6 was used to hydrolyze cod protein in the presence and absence of pro-oxidants at pH 8 and 36°C to achieve 20% degree of hydrolysis. Results from thiobarbituric acid reactive substances (TBARS) and sensory analysis indicate that oxidation can develop rapidly during hydrolysis. A cellular antioxidant assay using a HepG2 cell model indicated a negative impact of oxidation products on antioxidant properties of the FPH while results obtained in chemical assays showed a negligible impact. Results from a dendritic cell model indicating that oxidation products may affect anti-inflammatory activity in the body. This study provides important information regarding bioactive FPH.

  16. A discretized model for enzymatic hydrolysis of cellulose in a fed-batch process.

    PubMed

    Tervasmäki, Petri; Sotaniemi, Ville; Kangas, Jani; Taskila, Sanna; Ojamo, Heikki; Tanskanen, Juha

    2017-03-01

    In the enzymatic hydrolysis of cellulose, several phenomena have been proposed to cause a decrease in the reaction rate with increasing conversion. The importance of each phenomenon is difficult to distinguish from batch hydrolysis data. Thus, kinetic models for the enzymatic hydrolysis of cellulose often suffer from poor parameter identifiability. This work presents a model that is applicable to fed-batch hydrolysis by discretizing the substrate based on the feeding time. Different scenarios are tested to explain the observed decrease in reaction rate with increasing conversion, and comprehensive assessment of the parameter sensitivities is carried out. The proposed model performed well in the broad range of experimental conditions used in this study and when compared to literature data. Furthermore, the use of data from fed-batch experiments and discretization of the model substrate to populations was found to be very informative when assessing the importance of the rate-decreasing phenomena in the model.

  17. Dynamic modeling and validation of a lignocellulosic enzymatic hydrolysis process--a demonstration scale study.

    PubMed

    Prunescu, Remus Mihail; Sin, Gürkan

    2013-12-01

    The enzymatic hydrolysis process is one of the key steps in second generation biofuel production. After being thermally pretreated, the lignocellulosic material is liquefied by enzymes prior to fermentation. The scope of this paper is to evaluate a dynamic model of the hydrolysis process on a demonstration scale reactor. The following novel features are included: the application of the Convection-Diffusion-Reaction equation to a hydrolysis reactor to assess transport and mixing effects; the extension of a competitive kinetic model with enzymatic pH dependency and hemicellulose hydrolysis; a comprehensive pH model; and viscosity estimations during the course of reaction. The model is evaluated against real data extracted from a demonstration scale biorefinery throughout several days of operation. All measurements are within predictions uncertainty and, therefore, the model constitutes a valuable tool to support process optimization, performance monitoring, diagnosis and process control at full-scale studies.

  18. Enzymatic Hydrolysis of Pretreated Fibre Pressed Oil Palm Frond by using Sacchariseb C6

    NASA Astrophysics Data System (ADS)

    Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Rahman, R. A.; Illias, R. M.

    2017-06-01

    Enzymatic hydrolysis becomes a prominent technology for conversion of cellulosic biomass to its glucose monomers that requires an action of cellulolytic enzymes in a sequential and synergistic manner. In this study, the effect of agitation speed, glucan loading, enzyme loading, temperature and reaction time on the production of glucose from fibre pressed oil palm frond (FPOPF) during enzymatic hydrolysis was screened by a half factorial design 25-1 using Response Surface Methodology (RSM). The FPOPF sample was first delignified by alkaline pretreatment at 4.42 (w/v) sodium hydroxide for an hour prior to enzymatic hydrolysis using commercial cellulase enzyme, Sacchariseb C6. The effect of enzymatic hydrolysis on the structural of FPOPF has been evaluated by Scanning Electron Microscopy (SEM) analysis. Characterization of raw FPOPF comprised of 4.5 extractives, 40.7 glucan, 26.1 xylan, 26.2 lignin and 1.8 ash, whereas for pretreated FPOPF gave 0.3 extractives, 61.4 glucan, 20.4 xylan, 13.3 lignin and 1.3 ash. From this study, it was found that the best enzymatic hydrolysis condition yielded 33.01 ± 0.73 g/L of glucose when performed at 200 rpm of agitation speed, 60 FPU/mL of enzyme loading, 4 (w/w) of glucan loading, temperature at 55 □ and 72 hours of reaction time. The model obtained was significant with p-value <0.0001 as verified by the analysis of variance (ANOVA). The coefficient of determination (R2) from ANOVA study was 0.9959. Overall, it can be concluded that addition of Sacchariseb C6 during enzymatic hydrolysis from pretreated FPOPF produce high amount of glucose that enhances it potential for industrial application. This glucose can be further used to produce high-value products.

  19. Mechanistic kinetic models of enzymatic cellulose hydrolysis-A review.

    PubMed

    Jeoh, Tina; Cardona, Maria J; Karuna, Nardrapee; Mudinoor, Akshata R; Nill, Jennifer

    2017-07-01

    Bioconversion of lignocellulose forms the basis for renewable, advanced biofuels, and bioproducts. Mechanisms of hydrolysis of cellulose by cellulases have been actively studied for nearly 70 years with significant gains in understanding of the cellulolytic enzymes. Yet, a full mechanistic understanding of the hydrolysis reaction has been elusive. We present a review to highlight new insights gained since the most recent comprehensive review of cellulose hydrolysis kinetic models by Bansal et al. (2009) Biotechnol Adv 27:833-848. Recent models have taken a two-pronged approach to tackle the challenge of modeling the complex heterogeneous reaction-an enzyme-centric modeling approach centered on the molecularity of the cellulase-cellulose interactions to examine rate limiting elementary steps and a substrate-centric modeling approach aimed at capturing the limiting property of the insoluble cellulose substrate. Collectively, modeling results suggest that at the molecular-scale, how rapidly cellulases can bind productively (complexation) and release from cellulose (decomplexation) is limiting, while the overall hydrolysis rate is largely insensitive to the catalytic rate constant. The surface area of the insoluble substrate and the degrees of polymerization of the cellulose molecules in the reaction both limit initial hydrolysis rates only. Neither enzyme-centric models nor substrate-centric models can consistently capture hydrolysis time course at extended reaction times. Thus, questions of the true reaction limiting factors at extended reaction times and the role of complexation and decomplexation in rate limitation remain unresolved. Biotechnol. Bioeng. 2017;114: 1369-1385. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Pretreatment with ammonia water for enzymatic hydrolysis of corn husk, bagasse, and switchgrass.

    PubMed

    Kurakake, M; Kisaka, W; Ouchi, K; Komaki, T

    2001-03-01

    Bagasse, corn husk, and switchgrass were pretreated with ammonia water to enhance enzymatic hydrolysis. The sample (2 g) was mixed with 1-6 mL ammonia water (25-28% ammonia) and autoclaved at 120 degreesC for 20 min. After treatment, the product was vacuum-dried to remove ammonia gas. The dried solid could be used immediately in the enzymatic hydrolysis without washing. The enzymatic hydrolysis was effectively improved with more than 0.5 and 1 mL ammonia water/g for corn husk and bagasse, respectively. In bagasse, glucose, xylose, and xylobiose were the main products. The adsorption of CMCase and xylanase was related to the initial rate of enzymatic hydrolysis. In corn husks, arabinoxylan extracted by pretreatment was substantially unhydrolyzed because of the high ratio of arabinose to xylose (0.6). The carbohydrate yields from cellulose and hemicellulose were 72.9% and 82.4% in bagasse, and 86.2% and 91.9% in corn husk, respectively. The ammonia/water pretreatment also benefited from switchgrass (Miscanthus sinensis and Solidago altissima L.) hydrolysis.

  1. Effect of limited enzymatic hydrolysis on linoleic acid binding properties of β-lactoglobulin.

    PubMed

    Sponton, Osvaldo E; Perez, Adrián A; Carrara, Carlos; Santiago, Liliana G

    2014-03-01

    β-Lactoglobulin (BLG) is a member of lipocalin family, proteins with ability to bind small hydrophobic ligands, such as retinol, vitamins and fatty acids. Moreover, BLG is susceptible to protease action producing a wide range of polypeptides depending on the hydrolysis degree (HD). In the present work, the effect of limited enzymatic hydrolysis on fatty acid binding properties of BLG was studied. Linoleic acid (LA) was used as a model fatty acid. Limited enzymatic hydrolysis was performed using α-chymotrypsin immobilised on agarose microparticles. BLG hydrolysates were produced at HD: 1%, 3% and 5%. In order to determine the influence of HD on BLG molecular weight SDS-PAGE was used. BLG structural modification and LA binding properties were monitored by means of fluorescence spectroscopic techniques. The increase in HD produced: (i) a BLG degradation and a molecular weight distribution of BLG hydrolysates and (ii) an increased exposition of buried hydrophobic residues, however it was observed a decrease in surface hydrophobicity possibly due to a deterioration of hydrophobic protein domains. It was observed that enzymatic hydrolysis treatment produced a decrease in BLG ability for binding LA. It was concluded that limited enzymatic hydrolysis could deteriorate the specific site on BLG structure necessary for binding LA.

  2. Enzymatic hydrolysis and fermentation of dilute acid pretreated cornstalk to biohydrogen

    NASA Astrophysics Data System (ADS)

    Pan, C. M.; Fan, Y. T.; Hou, H. W.

    2010-03-01

    The coupling method of acid pretreatment and enzymatic hydrolysis of cornstalk for hydrogen production was investigated in this study. Experimental results showed that temperature, pH and enzyme loading all had an individual significant influence on soluble sugar yield and Ps. The optimum condition for soluble sugar was close to that for Ps. The maximum hydrogen yield from cornstalk by anaerobic mixed microflora was 209.8 ml/g-TVS on the optimum enzymatic hydrolysis condition which was 52 °C of temperature, pH4.8 and 9.4 IU/g of enzyme loading.

  3. Exploring crystalline-structural variations of cellulose during alkaline pretreatment for enhanced enzymatic hydrolysis.

    PubMed

    Ling, Zhe; Chen, Sheng; Zhang, Xun; Xu, Feng

    2017-01-01

    The study aimed to explore the crystallinity and crystalline structure of alkaline pretreated cellulose. The enzymatic hydrolysis followed by pretreatment was conducted for measuring the efficiency of sugar conversion. For cellulose Iβ dominated samples, alkaline pretreatment (<8wt%) caused increased cellulose crystallinity and depolymerized hemicelluloses, that were superimposed to affect the enzymatic conversion to glucose. Varying crystallite sizes and lattice spacings indicated the separation of cellulose crystals during mercerization (8-12wt% NaOH). Completion of mercerization was proved under higher alkaline concentration (14-18wt% NaOH), leading to distortion of crystalline cellulose to some extent. Cellulose II crystallinity showed a stimulative impact on enzymatic hydrolysis due to the weakened hydrophobic interactions within cellulose chains. The current study may provide innovative explanations for enhanced enzymatic digestibility of alkaline pretreated lignocellulosic materials.

  4. Influence of enzymatic hydrolysis on the allergenic reactivity of processed cashew and pistachio.

    PubMed

    Cuadrado, Carmen; Cheng, Hsiaopo; Sanchiz, Africa; Ballesteros, Isabel; Easson, Michael; Grimm, Casey C; Dieguez, M Carmen; Linacero, Rosario; Burbano, Carmen; Maleki, Soheila J

    2018-02-15

    Cashew and pistachio allergies are considered a serious health problem. Previous studies have shown that thermal processing, pressurization and enzymatic hydrolysis may reduce the allergenic properties of food by changing the protein structure. This study assesses the allergenic properties of cashew and pistachio after thermal treatment (boiling and autoclaving), with or without pressure (autoclaving), and multiple enzymatic treatments under sonication, by SDS-PAGE, western blot and ELISA, with serum IgE of allergic individuals, and mass spectroscopy. Autoclaving and enzymatic hydrolysis under sonication separately induced a measurable reduction in the IgE binding properties of pastes made from treated cashew and pistachio nuts. These treatments were more effective with pistachio allergens. However, heat combined with enzymatic digestion was necessary to markedly lower IgE binding to cashew allergens. The findings identify highly effective simultaneous processing conditions to reduce or even abolish the allergenic potency of cashew and pistachio. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Trichoderma reesei cellobiohydrolase II is associated with the outer membrane when overexpressed in Escherichia coli.

    PubMed

    Abdeljabbar, Diya M; Song, Hank J; Link, A James

    2012-01-01

    Cellulose degradation is essential for the future production of many advanced biofuels. Cellulases from the filamentous fungus Trichoderma reesei are among the most efficient enzymes for the hydrolysis of cellulosic materials. One of the cellulases from T. reesei, cellobiohydrolase II (CBH2), was studied because of its industrial relevance and proven enzymatic activity. Using both crude and rigorous membrane fractionation methods we show that full length T. reesei CBH2 is exclusively localized to the outer membrane when expressed recombinantly in Escherichia coli. Even fusing signal sequence-free maltose-binding protein to the N-terminus of CBH2, which has been shown to increase solubility of other proteins, did not prevent the outer membrane localization of CBH2. These results highlight the difficulties in producing fungal cellulases in bacterial hosts and provide a stepping stone for future cellulase engineering efforts.

  6. Bioabatement with xylanase supplementation to reduce enzymatic hydrolysis inhibitors

    USDA-ARS?s Scientific Manuscript database

    Bioabatement, using the fungus Coniochaeta ligniaria NRRL30616 can effectively eliminate enzyme inhibitors from pretreated biomass hydrolysis. However, our recent research suggested that bioabatement had no beneficial effect on removing xylo-oligomers which were identified as strong inhibitors to ce...

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

    PubMed

    Lai, Chenhuan; Tu, Maobing; Shi, Zhiqiang; Zheng, Ke; Olmos, Luis G; Yu, Shiyuan

    2014-07-01

    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 49.3% to 68.6% and from 41.2% to 60.8%, respectively. In contrast, the addition of EOL-LP decreased the 72 h hydrolysis yields of OPSG and OPLP to 42.0% and 38.1%, respectively. A strong correlation between the distribution coefficients of cellulase enzymes on lignins and the changes of hydrolysis yields indicated that the inhibitory or stimulatory effects of organosolv lignins on enzymatic hydrolysis were governed by the distribution coefficients (R). The different R values probably were related to the electrostatic interactions, hydrophobic interactions and hydrogen bondings between enzymes and lignin.

  8. Water sorption in pretreated grasses as a predictor of enzymatic hydrolysis yields.

    PubMed

    Williams, Daniel L; Crowe, Jacob D; Ong, Rebecca G; Hodge, David B

    2017-09-01

    This work investigated the impact of two alkaline pretreatments, ammonia fiber expansion (AFEX) and alkaline hydrogen peroxide (AHP) delignification performed over a range of conditions on the properties of corn stover and switchgrass. Changes in feedstock properties resulting from pretreatment were subsequently compared to enzymatic hydrolysis yields to examine the relationship between enzymatic hydrolysis and cell wall properties. The pretreatments function to increase enzymatic hydrolysis yields through different mechanisms; AFEX pretreatment through lignin relocalization and some xylan solubilization and AHP primarily through lignin solubilization. An important outcome of this work demonstrated that while changes in lignin content in AHP-delignified biomass could be clearly correlated to improved response to hydrolysis, compositional changes alone in AFEX-pretreated biomass could not explain differences in hydrolysis yields. We determined the water retention value, which characterizes the association of water with the cell wall of the pretreated biomass, can be used to predict hydrolysis yields for all pretreated biomass within this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Alternatives to Trichoderma reesei in biofuel production.

    PubMed

    Gusakov, Alexander V

    2011-09-01

    Mutant strains of Trichoderma reesei are considered indisputable champions in cellulase production among biomass-degrading fungi. So, it is not surprising that most R&D projects on bioethanol production from lignocellulosics have been based on using T. reesei cellulases. The present review focuses on whether any serious alternatives to T. reesei enzymes in cellulose hydrolysis exist. Although not widely accepted, more and more data have been accumulated that demonstrate that fungi belonging to the genera Penicillium, Acremonium and Chrysosporium might represent such alternatives because they are competitive to T. reesei on some important parameters, such as protein production level, cellulase hydrolytic performance per unit of activity or milligram of protein.

  10. [Mechanisms and regulation of enzymatic hydrolysis of cellulose in filamentous fungi: classical cases and new models].

    PubMed

    Gutiérrez-Rojas, Ivonne; Moreno-Sarmiento, Nubia; Montoya, Dolly

    2015-01-01

    Cellulose is the most abundant renewable carbon source on earth. However, this polymer structure comprises a physical and chemical barrier for carbon access, which has limited its exploitation. In nature, only a few percentage of microorganisms may degrade this polymer by cellulase expression. Filamentous fungi are one of the most active and efficient groups among these microorganisms. This review describes similarities and differences between cellulase activity mechanisms and regulatory mechanisms controlling gene expression for 3 of the most studied cellulolytic filamentous fungi models: Trichoderma reesei, Aspergillus niger and Aspergillus nidulans, and the recently described model Neurospora crassa. Unlike gene expression mechanisms, it was found that enzymatic activity mechanisms are similar for all the studied models. Understanding the distinctive elements of each system is essential for the development of strategies for the improvement of cellulase production, either by providing the optimum environment (fermentation conditions) or increasing gene expression in these microorganisms by genetic engineering.

  11. Stochastic molecular model of enzymatic hydrolysis of cellulose for ethanol production

    PubMed Central

    2013-01-01

    Background During cellulosic ethanol production, cellulose hydrolysis is achieved by synergistic action of cellulase enzyme complex consisting of multiple enzymes with different mode of actions. Enzymatic hydrolysis of cellulose is one of the bottlenecks in the commercialization of the process due to low hydrolysis rates and high cost of enzymes. A robust hydrolysis model that can predict hydrolysis profile under various scenarios can act as an important forecasting tool to improve the hydrolysis process. However, multiple factors affecting hydrolysis: cellulose structure and complex enzyme-substrate interactions during hydrolysis make it diffucult to develop mathematical kinetic models that can simulate hydrolysis in presence of multiple enzymes with high fidelity. In this study, a comprehensive hydrolysis model based on stochastic molecular modeling approch in which each hydrolysis event is translated into a discrete event is presented. The model captures the structural features of cellulose, enzyme properties (mode of actions, synergism, inhibition), and most importantly dynamic morphological changes in the substrate that directly affect the enzyme-substrate interactions during hydrolysis. Results Cellulose was modeled as a group of microfibrils consisting of elementary fibrils bundles, where each elementary fibril was represented as a three dimensional matrix of glucose molecules. Hydrolysis of cellulose was simulated based on Monte Carlo simulation technique. Cellulose hydrolysis results predicted by model simulations agree well with the experimental data from literature. Coefficients of determination for model predictions and experimental values were in the range of 0.75 to 0.96 for Avicel hydrolysis by CBH I action. Model was able to simulate the synergistic action of multiple enzymes during hydrolysis. The model simulations captured the important experimental observations: effect of structural properties, enzyme inhibition and enzyme loadings on the

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

    PubMed

    Huang, Yang; Sun, Shaolong; Huang, Chen; Yong, Qiang; Elder, Thomas; Tu, Maobing

    2017-01-01

    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. We examined the physicochemical properties and the structures of ethanol organosolv lignins (EOL) from hardwood and softwood and ascertained the association between lignin properties and their inhibitory and stimulatory effects on enzymatic hydrolysis. The zeta potential and hydrophobicity of EOL lignin samples, isolated from organosolv pretreatment of cottonwood (CW), black willow (BW), aspen (AS), eucalyptus (EH), and loblolly pine (LP), were determined and correlated with their effects on enzymatic hydrolysis of Avicel. EOLs from CW, BW, and AS improved the 72 h hydrolysis yield by 8-12%, while EOLs from EH and LP decreased the 72 h hydrolysis yield by 6 and 16%, respectively. The results showed a strong correlation between the 72 h hydrolysis yield with hydrophobicity and zeta potential. The correlation indicated that the hydrophobicity of EOL had a negative effect and the negative zeta potential of EOL had a positive effect. HSQC NMR spectra showed that β-O-4 linkages in lignin react with ethanol to form an α-ethoxylated β-O-4' substructure (A') during organosolv pretreatment. Considerable amounts of C2,6-H2,6 correlation in p-hydroxybenzoate (PB) units were observed for EOL-CW, EOL-BW, and EOL-AS, but not for EOL-EH and EOL-LP. This study revealed that the effect of lignin on enzymatic hydrolysis is a function of both hydrophobic interactions and electrostatic repulsions. The lignin inhibition is controlled by lignin hydrophobicity and the lignin stimulation is governed by the negative zeta potential. The net effect of lignin depends on the combined

  13. Simultaneous pretreatment and enzymatic hydrolysis of forage biomass

    SciTech Connect

    Henk, L.; Linden, J.C.

    1993-12-31

    Sweet sorghum is an attractive fermentation feedstock because as much as 40% of the dry weight consists of readily femented sugars such as sucrose, glucose and frutose. Cellulose and hemicellulose comprise another 50%. However, if this material is to be used a year-round feedstock for ethanol production, a stable method of storage must be developed to maintain the sugar content. A modified version of the traditional ensiling process is made effective by the addition of cellulolytic/hemicellulolytic enzymes and lactic acid bacteria to freshly chopped sweet sorghum prior to the production of silage. In situ hydrolysis of cellulose and hemicellulose occurs concurrently with the acidic ensiling fementation. By hydolyzing the acetyl groups using acetyl xylan esterase and 3-0-methyl glucuronyl side chains using pectinase from hemicellulose, cellulose becomes accessible to hydrolysis by cellulase, both during in situ ensiling with enzymes and in the simultaneous saccharification and fermentation (SSF) to ethanol.

  14. Novel agents for enzymatic and fungal hydrolysis of stevioside

    PubMed Central

    Milagre, H.M.S.; Martins, L.R.; Takahashi, J.A.

    2009-01-01

    A comparative study on the potential of some biological agents to perform the hydrolysis of stevioside was carried out, aiming at establishing an alternative methodology to achieve the aglycon steviol or its rearranged derivative isosteviol, in high yields to be used in the preparation of novel bioactive compounds. Hydrolysis reactions were performed by using filamentous fungi (Aspergillus niger, Rhizopus stolonifer and Rhizopus arrhizus), a yeast (Saccharomyces cerevisiae) and enzymes (pancreatin and lipases PL250 and VFL 8000). Pancreatin showed the best hydrolytic activity, furnishing isosteviol at 93.9% of yield, at pH 4.0, using toluene as a co-solvent. Steviol was produced using both pancreatin at pH 7.0 (20.2% yield) and A. niger at pH 7 (20.8% yield). PMID:24031374

  15. Enhancing the enzymatic hydrolysis of cellulosic materials using simultaneous ball milling.

    PubMed

    Mais, Ursula; Esteghlalian, Ali R; Saddler, John N; Mansfield, Shawn D

    2002-01-01

    One of the limiting factors restricting the effective and efficient bioconversion of softwood-derived lignocellulosic residues is the recalcitrance of the substrate following pretreatment. Consequently, the ensuing enzymatic process requires relatively high enzyme loadings to produce monomeric carbohydrates that are readily fermentable by ethanologenic microorganisms. In an attempt to circumvent the need for larger enzyme loadings, a simultaneous physical and enzymatic hydrolysis treatment was evaluated. A ball-mill reactor was used as the digestion vessel, and the extent and rate of hydrolysis were monitored. Concurrently, enzyme adsorption profiles and the rate of conversion during the course of hydrolysis were monitored. alpha-Cellulose, employed as a model substrate, and SO2-impregnated steam-exploded Douglas-fir wood chips were assessed as the cellulosic substrates. The softwood-derived substrate was further posttreated with water and hot alkaline hydrogen peroxide to remove >90% of the original lignin. Experiments at different reaction conditions were evaluated, including substrate concentration, enzyme loading, reaction volumes, and number of ball beads employed during mechanical milling. It was apparent that the best conditions for the enzymatic hydrolysis of alpha-cellulose were attained using a higher number of beads, while the presence of air-liquid interface did not seem to affect the rate of saccharification. Similarly, when employing the lignocellulosic substrate, up to 100% hydrolysis could be achieved with a minimum enzyme loading (10 filter paper units/g of cellulose), at lower substrate concentrations and with a greater number of reaction beads during milling. It was apparent that the combined strategy of simultaneous ball milling and enzymatic hydrolysis could improve the rate of saccharification and/or reduce the enzyme loading required to attain total hydrolysis of the carbohydrate moieties.

  16. Effect of bovine serum albumin (BSA) on enzymatic cellulose hydrolysis.

    PubMed

    Wang, Hui; Mochidzuki, Kazuhiro; Kobayashi, Shinichi; Hiraide, Hatsue; Wang, Xiaofen; Cui, Zongjun

    2013-06-01

    Bovine serum albumin (BSA) was added to filter paper during the hydrolysis of cellulase. Adding BSA before the addition of the cellulase enhances enzyme activity in the solution, thereby increasing the conversion rate of cellulose. After 48 h of BSA treatment, the BSA adsorption quantities are 3.3, 4.6, 7.8, 17.2, and 28.3 mg/g substrate, each with different initial BSA concentration treatments at 50 °C; in addition, more cellulase was adsorbed onto the filter paper at 50 °C compared with 35 °C. After 48 h of hydrolysis, the free-enzyme activity could not be measured without the BSA treatment, whereas the remaining activity of the filter paper activity was approximately 41 % when treated with 1.0 mg/mL BSA. Even after 96 h of hydrolysis, 25 % still remained. Meanwhile, after 48 h of incubation without substrate, the remaining enzyme activities were increased 20.7 % (from 43.7 to 52.7 %) and 94.8 % (from 23.3 to 45.5 %) at 35 and 50 °C, respectively. Moreover, the effect of the BSA was more obvious at 35 °C compared with 50 °C. When using 15 filter paper cellulase units per gram substrate cellulase loading at 50 °C, the cellulose conversion was increased from 75 % (without BSA treatment) to ≥90 % when using BSA dosages between 0.1 and 1.5 mg/mL. Overall, these results suggest that there are promising strategies for BSA treatment in the reduction of enzyme requirements during the hydrolysis of cellulose.

  17. The enzymatic hydrolysis of leather waste with chromium recycling

    SciTech Connect

    Kim, M.S.; Clesceri, L.S.

    1996-11-01

    The work of Taylor et al. (1990) has shown the potential for alkaline hydrolase enzymes for the solubilization of waste from the tanning industry. The authors have carried this work further to examine the mechanism whereby enzymes release chromium from leather waste. An alkaline digest of waste leather was used in this work. Treatment with strong alkali produced a thick slurry that contained 7,000 ppm chromium. The objective of this work is to optimize a closed cycle system for the recycling of chromium salts for tanning as well as a chrome-free product for use as a fertilizer. The authors are able to track the progress of the leather protein hydrolysis with polyacrylamide gel electrophoresis (PAGE). By means of PAGE, it is possible to determine the relationship between chromium release and the extent of protein hydrolysis. Rate constant for hydrolysis and chromium release have been developed for various hydrolysis conditions. Chemical precipitation of chromium from the hydrolysate results in a purified product for reuse in tanning. The chrome-free hydrolysate can be applied as a fertilizer either directly or as a dried product. There are more than 56,000 metric tons of tannery waste produced annually in the US. The majority of the organic solids can be converted into high quality fertilizers. Since the nitrogen is organic rather than inorganic, release is at a controlled rate since the microbody in the soil must make the nitrogen available for plant growth. Leather manufacturing is a world-wide industry. Conversion of leather waste to fertilizers can improve global productivity as well as solve a waste problem.

  18. Allergenicity of Peanut Proteins is Retained Following Enzymatic Hydrolysis

    USDA-ARS?s Scientific Manuscript database

    Rationale: Hydrolysis of peanut proteins by food-grade enzymes may reduce allergenicity and could lead to safer forms of immunotherapy. Methods: Light roasted peanut flour extracts were digested with pepsin (37°C, pH 2), Alcalase (60°C pH 8), or Flavourzyme (50°C, pH 7) up to 1 hr, or sequentially w...

  19. Effect of high hydrostatic pressure on the enzymatic hydrolysis of bovine serum albumin.

    PubMed

    De Maria, Serena; Ferrari, Giovanna; Maresca, Paola

    2017-08-01

    The extent of enzymatic proteolysis mainly depends on accessibility of the peptide bonds, which stabilize the protein structure. The high hydrostatic pressure (HHP) process is able to induce, at certain operating conditions, protein displacement, thus suggesting that this technology can be used to modify protein resistance to the enzymatic attack. This work aims at investigating the mechanism of enzymatic hydrolysis assisted by HHP performed under different processing conditions (pressure level, treatment time). Bovine serum albumin was selected for the experiments, solubilized in sodium phosphate buffer (25 mg mL(-1) , pH 7.5) with α-chymotrypsin or trypsin (E/S ratio = 1/10) and HPP treatment (100-500 MPa, 15-25 min). HHP treatment enhanced the extent of the hydrolysis reaction of globular proteins, being more effective than conventional hydrolysis. At HHP treatment conditions maximizing the protein unfolding, the hydrolysis degree of proteins was increased as a consequence of the increased exposure of peptide bonds to the attack of proteolytic enzymes. The maximum hydrolysis degree (10% and 7% respectively for the samples hydrolyzed with α-chymotrypsin and trypsin) was observed for the samples processed at 400 MPa for 25 min. At pressure levels higher than 400 MPa the formation of aggregates was likely to occur; thus the degree of hydrolysis decreased. Protein unfolding represents the key factor controlling the efficiency of HHP-assisted hydrolysis treatments. The peptide produced under high pressure showed lower dimensions and a different structure with respect to those of the hydrolysates obtained when the hydrolysis was carried out at atmospheric pressure, thus opening new frontiers of application in food science and nutrition. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  20. Is enzymatic hydrolysis a reliable analytical strategy to quantify glucuronidated and sulfated polyphenol metabolites in human fluids?

    PubMed

    Quifer-Rada, Paola; Martínez-Huélamo, Miriam; Lamuela-Raventos, Rosa M

    2017-07-19

    Phenolic compounds are present in human fluids (plasma and urine) mainly as glucuronidated and sulfated metabolites. Up to now, due to the unavailability of standards, enzymatic hydrolysis has been the method of choice in analytical chemistry to quantify these phase II phenolic metabolites. Enzymatic hydrolysis procedures vary in enzyme concentration, pH and temperature; however, there is a lack of knowledge about the stability of polyphenols in their free form during the process. In this study, we evaluated the stability of 7 phenolic acids, 2 flavonoids and 3 prenylflavanoids in urine during enzymatic hydrolysis to assess the suitability of this analytical procedure, using three different concentrations of β-glucuronidase/sulfatase enzymes from Helix pomatia. The results indicate that enzymatic hydrolysis negatively affected the recovery of the precursor and free-form polyphenols present in the sample. Thus, enzymatic hydrolysis does not seem an ideal analytical strategy to quantify glucuronidated and sulfated polyphenol metabolites.

  1. Steam pretreatment of spruce forest residues: optimal conditions for biogas production and enzymatic hydrolysis.

    PubMed

    Janzon, Ron; Schütt, Fokko; Oldenburg, Saskia; Fischer, Elmar; Körner, Ina; Saake, Bodo

    2014-01-16

    Steam refining of non-debarked spruce forest residues was investigated as pretreatment for enzymatic hydrolysis as well as for biogas production. Pretreatment conditions were varied in the range of 190-220 °C, 5-10 min and 0-3.7% SO₂ according to a statistical design. For both applications highest product yields were predicted at 220 °C and 2.4% SO₂, whereas the reaction time had only a minor influence. The conformity of the model results allows the conclusion that enzymatic hydrolysis is a suitable test method to evaluate the degradability of lignocellulosic biomass in the biogas process. In control experiments under optimal conditions the results of the model were verified. The yield of total monomeric carbohydrates after enzymatic hydrolysis was equivalent to 55% of all theoretically available polysaccharides. The corresponding biogas yield from the pretreated wood amounted to 304 mL/gODM. Furthermore, furans produced under optimal process conditions showed no inhibitory effect on biogas production. It can be concluded that steam refining opens the structure of wood, thus improving the enzymatic hydrolysis of the polysaccharides to fermentable monomeric sugars and subsequently enabling a higher and faster production of biogas. Anaerobic fermentation of pretreated wood is a serious alternative to alcoholic fermentation especially when low quality wood grades and residues are used. Anaerobic digestion should be further investigated in order to diversify the biorefinery options for lignocellulosic materials. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Understanding the fundamental mechanism behind accumulation of oligosaccharides during high solids loading enzymatic hydrolysis

    USDA-ARS?s Scientific Manuscript database

    During enzymatic hydrolysis of biomass, polysaccharides are cleaved by glycosyl hydrolases to soluble oligosaccharides and further hydrolyzed by ß-glucosidase, ß-xylosidase and other enzymes to monomeric sugars. However, commercial enzyme mixtures do not hydrolyze all of these oligosaccharides and v...

  3. Enzymatic Hydrolysis of Peanut Flour Produces Bioactive Peptides with Reduced Allergenicity

    USDA-ARS?s Scientific Manuscript database

    Peanut allergy is one of the most severe food allergies due to its life-threatening nature and persistency. Current immunotherapy methods, though effective, are often accompanied by allergic side-effects. Enzymatic hydrolysis of peanut flour has the potential to produce bioactive peptides with impro...

  4. Enzymatic hydrolysis of cellulose in a membrane bioreactor: assessment of operating conditions.

    PubMed

    Liu, Jianguo; Lu, Jianren; Cui, Zhanfeng

    2011-06-01

    The optimization of operating conditions for cellulose hydrolysis was systemically undertaken using an ultra-scaled down membrane bioreactor based on the parameter scanning ultrafiltration apparatus. The bioconversion of cellulose saccharification was carried out with freely suspended cellulase from Aspergillus niger as the biocatalyst. The polyethersulfone ultrafiltration membranes with a molecular weight cutoff of 10 kDa were used to construct the enzymatic membrane bioreactor, with the membrane showing a complete retaining of cellulase and cellobiase. The influence of solution pH, temperature, salt (NaCl) concentration, presence of cellobiase, cellulose-to-enzyme ratio and stirring speed on reducing sugar production was examined. The results showed that the addition of an appropriate amount of NaCl or cellobiase had a positive effect on reducing sugar formation. Under the identified optimal conditions, cellulose hydrolysis in the enzymatic membrane bioreactor was tested for a long period of time up to 75 h, and both enzymes and operation conditions demonstrated good stability. Also, the activation energy (E(a)) of the enzymatic hydrolysis, with a value of 34.11 ± 1.03 kJ mol(-1), was estimated in this study. The operational and physicochemical conditions identified can help guide the design and operation of enzymatic membrane bioreactors at the industrial scale for cellulose hydrolysis.

  5. Biological pretreatment of corn stover with white-rot fungus for improved enzymatic hydrolysis

    USDA-ARS?s Scientific Manuscript database

    Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. However, fungal pretreatment can cause carbohydrate loss and it is, th...

  6. Reducing sugar loss in enzymatic hydrolysis of ethylenediamine pretreated corn stover.

    PubMed

    Li, Wen-Chao; Li, Xia; Qin, Lei; Zhu, Jia-Qing; Han, Xiao; Li, Bing-Zhi; Yuan, Ying-Jin

    2017-01-01

    In this study, the effect of ethylenediamine (EDA) on enzymatic hydrolysis with different cellulosic substrates and the approaches to reduce sugar loss in enzymatic hydrolysis were investigated. During enzymatic hydrolysis, xylose yield reduced 21.2%, 18.1% and 13.0% with 7.5mL/L EDA for AFEX pretreated corn stover (CS), washed EDA pretreated CS and CS cellulose. FTIR and GPC analysis demonstrated EDA reacted with sugar and produced high molecular weight (MW) compounds. EDA was prone to react with xylose other than glucose. H2O2 and Na2SO3 cannot prevent sugar loss in glucose/xylose-EDA mixture, although they inhibited the browning and high MW compounds formation. By decreasing temperature to 30°C, the loss of xylose yield reduced to only 3.8%, 3.6% and 4.2% with 7.5mL/L EDA in the enzymatic hydrolysis of AFEX pretreated CS, washed EDA pretreated CS and CS cellulose.

  7. Sugar loss and enzyme inhibition due to oligosaccharides accumulation during high solids-loading enzymatic hydrolysis

    USDA-ARS?s Scientific Manuscript database

    Oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, ammonia fiber expansion: AFEX and extractive ammonia: EA). The methodology for large-scale separation of ...

  8. Lignin-based polyoxyethylene ether enhanced enzymatic hydrolysis of lignocelluloses by dispersing cellulase aggregates.

    PubMed

    Lin, Xuliang; Qiu, Xueqing; Yuan, Long; Li, Zihao; Lou, Hongming; Zhou, Mingsong; Yang, Dongjie

    2015-06-01

    Water-soluble lignin-based polyoxyethylene ether (EHL-PEG), prepared from enzymatic hydrolysis lignin (EHL) and polyethylene glycol (PEG1000), was used to improve enzymatic hydrolysis efficiency of corn stover. The glucose yield of corn stover at 72h was increased from 16.7% to 70.1% by EHL-PEG, while increase in yield with PEG4600 alone was 52.3%. With the increase of lignin content, EHL-PEG improved enzymatic hydrolysis of microcrystalline cellulose more obvious than PEG4600. EHL-PEG could reduce at least 88% of the adsorption of cellulase on the lignin film measured by quartz crystal microbalance with dissipation monitoring (QCM-D), while reduction with PEG4600 was 43%. Cellulase aggregated at 1220nm in acetate buffer analyzed by dynamic light scattering. EHL-PEG dispersed cellulase aggregates and formed smaller aggregates with cellulase, thereby, reduced significantly nonproductive adsorption of cellulase on lignin and enhanced enzymatic hydrolysis of lignocelluloses. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Effects of enzymatic hydrolysis of protein on the pasting properties of different types of wheat flour.

    PubMed

    Chen, J S; Wang, S Y; Deng, Z Y; Zhang, X Y; Feng, S L; Yuan, H Q; Tian, J C

    2012-05-01

    As one of the most effective methods to modify proteins, enzymatic hydrolysis is used widely in the preparation of wheat products in the food industry. During the same process, starch pasting occurs frequently. The effects of wheat protein hydrolysis with papain, pepsin, and trypsin on the pasting properties of 3 different kinds of flour were investigated in 5 concentrations. Results showed that the peak viscosity, trough, final, and integral area of pasting curve of these flours decreased with increasing enzymatic hydrolysis of protein, and decreased significantly with the increasing enzyme concentrations. Medium-gluten flour was the least sensitive to enzymatic activity and weak-gluten the most sensitive. Downtrends appeared with increasing papain and trypsin concentrations in the form of breakdown. Enzymes had no significant different effect on the peak times of strong- and medium-gluten flour, but prolonged peak time slightly in weak-gluten flour. The pasting time and temperature of strong- and medium-gluten flour were significantly increased in a concentration-dependent manner. However, there were no significant effects on the pasting times of weak-gluten flour. These results could supply a basis for utilization of enzymatic hydrolysis of wheat protein in food industry and for further studies into the interactions between hydrolyzed protein and starch in food or processing industries.

  10. Eliminating inhibition of enzymatic hydrolysis by lignosulfonate in unwashed sulfite-pretreated aspen using metal salts

    Treesearch

    Hao Liu; Junyong Zhu

    2010-01-01

    This study demonstrated the efficiency of Ca(II) and Mg(II) in removing inhibition of enzymatic hydrolysis by lignosulfonate through non-productive adsorption of enzymes. Adding 1 mmol/g cellulose of either metal salt restores approximately 65% of the activity lost when a pure cellulose/cellulase solution is spiked with lignosulfonate. Addition of either Ca(II) or Mg(...

  11. Acceleration of the Enzymatic Hydrolysis of Cotton Waste Celluloses by Low Intensity Uniform Ultrasound Field

    USDA-ARS?s Scientific Manuscript database

    The cost-competitive production of bio-ethanol and other biofuels is currently impeded, mostly by high cost and low efficiency of enzymatic hydrolysis of feedstock biomass and especially plant celluloses. Despite substantial reduction in the cost of production of cellulolytic enzymes in recent times...

  12. Effective of Microwave-KOH Pretreatment on Enzymatic Hydrolysis of Bamboo

    Treesearch

    Zhiqiang Li; Zehui Jiang; Yan Yu; Zhiyong Cai

    2012-01-01

    Bamboo, with its advantages of fast growth, short renovation, easy propagation and rich in cellulose and hemicellulose, is a potential feedstock for bioethanol or other biofuels production. The objective of this study was to examine the fea- sibility of microwave assistant KOH pretreatments to enhance enzymatic hydrolysis of bamboo. Pretreatment was car- ried out by...

  13. Enhanced enzymatic hydrolysis of kenaf core using irradiation and dilute acid

    NASA Astrophysics Data System (ADS)

    Lee, Byoung-Min; Jeun, Joon-Pyo; Kang, Phil-Hyun

    2017-01-01

    This study was performed to determine the effect of electron beam dose and enzymatic hydrolysis time for production of sugar such as glucose and xylose. After kenaf core was exposed to an irradiation dose that ranged from 0 to 500 kGy, the irradiated kenaf core was treated with a 3% (v/v) sulfuric acid solution using an autoclave for 5 h at 120 °C. The pretreated kenaf core was subsequently subjected to enzymatic hydrolysis at 50 °C in a shaking water bath at 150 rpm for 12, 24, 48, and 72 h. The determined enzyme activity rates were 70 FPU (Celluclast 1.5 L) and 40 CBU (Novozyme-188). The crystallinity index decreased from 50.6% in a non-pretreated kenaf core to 27.7% in kenaf core that was subjected to the two-stage pretreatment at dose of 500 kGy. The sugar yield of the two-stage pretreated kenaf core increased with an increase in irradiation dose. The sugar yield after 72 h of enzymatic hydrolysis was 73.6% at its highest with an irradiation dose of 500 kGy. The enhancement of enzymatic hydrolysis by two-stage pretreatment was more effective than non- and single pretreatment (36.9%, 40.6% and 44.0% in non-pretreatment, electron beam and dilute acid, respectively).

  14. [The development of the method for enzymatic hydrolysis for the extraction of toxic substances from the hair samples].

    PubMed

    Slustovskaya, Yu V; Krys'ko, M V; Strelova, O Yu

    The objective of the present study was to develop and validate the method for the extraction of toxic substances from the hair samples as exemplified by enzymatic hydrolysis of barbituric acid derivatives. The experiments were carried out with the use of laboratory animals (white female rats and albino guinea pigs) that had been daily given a phenobarbital solution per os during 4 months preceding the study. The hairs obtained from the experimental animals were subjected to acid hydrolysis with a 6 mole hydrochloric acid and enzymatic hydrolysis with the use of chymopsin, trypsin, chymotrypsin, and papain solutions. The analysis of the extracted materials was performed by means of gas chromatography with mass-selective detection. The application of the proposed method for enzymatic hydrolysis produced the better results than acid hydrolysis. This technique was validated. The results of the study made possible the comparative characteristic of the effectiveness of acid and enzymatic hydrolysis.

  15. Modeling enzymatic hydrolysis of lignocellulosic substrates using confocal fluorescence microscopy I: filter paper cellulose.

    PubMed

    Luterbacher, Jeremy S; Moran-Mirabal, Jose M; Burkholder, Eric W; Walker, Larry P

    2015-01-01

    Enzymatic hydrolysis is one of the critical steps in depolymerizing lignocellulosic biomass into fermentable sugars for further upgrading into fuels and/or chemicals. However, many studies still rely on empirical trends to optimize enzymatic reactions. An improved understanding of enzymatic hydrolysis could allow research efforts to follow a rational design guided by an appropriate theoretical framework. In this study, we present a method to image cellulosic substrates with complex three-dimensional structure, such as filter paper, undergoing hydrolysis under conditions relevant to industrial saccharification processes (i.e., temperature of 50°C, using commercial cellulolytic cocktails). Fluorescence intensities resulting from confocal images were used to estimate parameters for a diffusion and reaction model. Furthermore, the observation of a relatively constant bound enzyme fluorescence signal throughout hydrolysis supported our modeling assumption regarding the structure of biomass during hydrolysis. The observed behavior suggests that pore evolution can be modeled as widening of infinitely long slits. The resulting model accurately predicts the concentrations of soluble carbohydrates obtained from independent saccharification experiments conducted in bulk, demonstrating its relevance to biomass conversion work.

  16. Inhibition of cellulose enzymatic hydrolysis by laccase-derived compounds from phenols.

    PubMed

    Oliva-Taravilla, Alfredo; Tomás-Pejó, Elia; Demuez, Marie; González-Fernández, Cristina; Ballesteros, Mercedes

    2015-01-01

    The presence of inhibitors compounds after pretreatment of lignocellulosic materials affects the saccharification and fermentation steps in bioethanol production processes. Even though, external addition of laccases selectively removes the phenolic compounds from lignocellulosic prehydrolysates, when it is coupled to saccharification step, lower hydrolysis yields are attained. Vanillin, syringaldehyde and ferulic acid are phenolic compounds commonly found in wheat-straw prehydrolysate after steam-explosion pretreatment. These three phenolic compounds were used in this study to elucidate the inhibitory mechanisms of laccase-derived compounds after laccase treatment. Reaction products derived from laccase oxidation of vanillin and syringaldehyde showed to be the strongest inhibitors. The presence of these products causes a decrement on enzymatic hydrolysis yield of a model cellulosic substrate (Sigmacell) of 46.6 and 32.6%, respectively at 24 h. Moreover, a decrease in more than 50% of cellulase and β-glucosidase activities was observed in presence of laccase and vanillin. This effect was attributed to coupling reactions between phenoxyl radicals and enzymes. On the other hand, when the hydrolysis of Sigmacell was performed in presence of prehydrolysate from steam-exploded wheat straw a significant inhibition on enzymatic hydrolysis was observed independently of laccase treatment. This result pointed out that the other components of wheat-straw prehydrolysate are affecting the enzymatic hydrolysis to a higher extent than the possible laccase-derived products.

  17. Pretreatment and enzymatic hydrolysis of wheat straw (Triticum aestivum L.)--the impact of lignin relocation and plant tissues on enzymatic accessibility.

    PubMed

    Hansen, Mads A T; Kristensen, Jan Bach; Felby, Claus; Jørgensen, Henning

    2011-02-01

    Wheat straw is a potential feedstock for bioethanol production. This paper investigates tissues from whole internode sections subjected to hydrothermal pretreatment at 185°C and subsequent enzymatic hydrolysis up to 144 h. Analyses revealed an increase in surface lignin as hydrolysis progressed, which could be coupled to the gradual decrease in hydrolysis rate over time. The data support the hypothesis of lignin extraction from the cell wall matrix during pretreatment and deposition as droplets upon cooling. These droplets are assumed to accumulate during enzymatic hydrolysis. Additionally, after 144 h of enzymatic hydrolysis the cortex had vanished, exposing the heavier lignified vascular tissue. Accumulation of lignin droplets and exposure of residual lignin could be part of the explanation for the decreasing hydrolysis rate. Flattening of macrofibrils after pretreatment together with more indentations on the surfaces was also observed, possibly caused by a proposed synergistic effect of cellobiohydrolases and endoglucanases. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Phorbol diesters inhibit enzymatic hydrolysis of diacylglycerols in vitro.

    PubMed Central

    Chabbott, H; Cabot, M C

    1986-01-01

    The effect of phorbol 12-myristate 13-acetate (PMA) on diacylglycerol lipase activity was examined in rat serum, tissue, and cellular preparations by using di[14C]oleoylglycerol, [3H]palmitoylacetylglycerol, and membrane-resident phospholipase C-generated diacylglycerols as substrates. These experiments were conducted to address whether phorbol esters can mimic diacylglycerols in interacting with enzymes other than protein kinase C. Serum hydrolysis of palmitoylacetylglycerol, assayed by the formation of [3H]palmitic acid, was inhibited by PMA, 4-O-methyl-PMA, or phorbol 12,13-dibutyrate (in order of decreasing potency). The hydrolysis of palmitoylacetylglycerol was inhibited more than 40% by the addition of PMA at a 1:1 molar ratio with substrate. The inhibition resembled the competitive type, with a Ki of approximately 2.7 microM. PMA in the 10-60 microM range also inhibited hydrolysis of palmitoylacetylglycerol by lipases from rat brain microsomes and by homogenates of C3H/10T1/2 mouse fibroblasts. PMA was likewise inhibitory when assayed in an intramembrane enzyme-substrate milieu in which diacylglycerols were generated, in situ, by treatment of [3H]palmitate-labeled cell homogenates with phospholipase C. Collectively, these data demonstrate that PMA, which is now thought to act by mimicry of diacylglycerols, can inhibit the action of diacylglycerol lipase. It is possible that such a mechanism is linked to the multiplicity of responses elicited by phorbol diesters and that other agents may function by means of enzyme interactions (post-phospholipase C) to influence the levels of the cellular diacylglycerol mediators. PMID:3458169

  19. Effect of pH on cellulase production and morphology of Trichoderma reesei and the application in cellulosic material hydrolysis.

    PubMed

    Li, Chen; Yang, Zhenhua; Zhang, Ronglin He Can; Zhang, Dongyuan; Chen, Shulin; Ma, Lijuan

    2013-12-01

    A low-cost of cellulase achieved through improving fermentation technology remains a key requirement for commercialization of cellulosic biofuels and biochemicals. pH plays a very important role in the process of cellulase synthesis by Trichoderma reesei. In this work, effects of pH on the production and production rates of three cellulase components (endoglucanase, exoglucanase, β-glucosidase) and mycelial morphology were studied. Production rates of the cellulase components were kept highest and the mycelial morphology was maintained at the optimal status by developing a phased pH control strategy in order to improve cellulase production. Cellulase production in terms of filter paper activity and β-glucosidase production in batch fermentation increased 17.6% and 22%. Saccharification efficiency of the enzyme obtained by pH control was evaluated by hydrolyzing pretreated corn cob. Saccharification yield increased significantly (up to 26.2%) compared with that without pH control. These results add new knowledge on approach for improving cellulase production. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Enhanced enzymatic cellulose hydrolysis by subcritical carbon dioxide pretreatment of sugarcane bagasse.

    PubMed

    Zhang, Hongdan; Wu, Shubin

    2014-04-01

    Most biomass pretreatment processes for sugar production are run at low-solid concentration (<10 wt.%). Subcritical carbon dioxide (CO2) could provide a more sustainable pretreatment medium while using relative high-solid contents (15 wt.%). The effects of subcritical CO2 pretreatment of sugarcane bagasse to the solid and glucan recoveries at different pretreatment conditions were investigated. Subsequently, enzymatic hydrolysis at different hydrolysis time was applied to obtain maximal glucose yield, which can be used for ethanol fermentation. The maximum glucose yield in enzyme hydrolyzate reached 38.5 g based on 100g raw material after 72 h of enzymatic hydrolysis, representing 93.0% glucose in sugarcane bagasse. The enhanced digestibilities of subcritical CO2 pretreated sugarcane bagasse were due to the removal of hemicellulose, which were confirmed by XRD, FTIR, SEM, and TGA analyses.

  1. High-yield production of biosugars from Gracilaria verrucosa by acid and enzymatic hydrolysis processes.

    PubMed

    Kim, Se Won; Hong, Chae-Hwan; Jeon, Sung-Wan; Shin, Hyun-Jae

    2015-11-01

    Gracilaria verrucosa, the red alga, is a suitable feedstock for biosugar production. This study analyzes biosugar production by the hydrolysis of G. verrucosa conducted under various conditions (i.e., various acid concentrations, substrate concentrations, reaction times, and enzyme dosages). The acid hydrolysates of G. verrucosa yielded a total of 7.47g/L (37.4%) and 10.63g/L (21.26%) of reducing sugars under optimal small (30mL) and large laboratory-scale (1L) hydrolysis processes, respectively. Reducing sugar obtained from acid and enzymatic hydrolysates were 10% higher, with minimum by-products, than those reported in other studies. The mass balance for the small laboratory-scale process showed that the acid and enzymatic hydrolysates had a carbohydrate conversion of 57.2%. The mass balance approach to the entire hydrolysis process of red seaweed for biosugar production can be applied to other saccharification processes.

  2. Enzymatic hydrolysis and characterization of waste lignocellulosic biomass produced after dye bioremediation under solid state fermentation.

    PubMed

    Waghmare, Pankajkumar R; Kadam, Avinash A; Saratale, Ganesh D; Govindwar, Sanjay P

    2014-09-01

    Sugarcane bagasse (SCB) adsorbes 60% Reactive Blue172 (RB172). Providensia staurti EbtSPG able to decolorize SCB adsorbed RB172 up to 99% under solid state fermentation (SSF). The enzymatic saccharification efficiency of waste biomass after bioremediation of RB172 process (ddSCB) has been evaluated. The cellulolyitc crude enzyme produced by Phanerochaete chrysosporium used for enzymatic hydrolysis of native SCB and ddSCB which produces 0.08 and 0.3 g/L of reducing sugars respectively after 48 h of incubation. The production of hexose and pentose sugars during hydrolysis was confirmed by HPTLC. The effect of enzymatic hydrolysis on SCB and ddSCB has been evaluated by FTIR, XRD and SEM analysis. Thus, during dye biodegradation under SSF causes biological pretreatment of SCB which significantly enhanced its enzymatic saccharification. Adsorption of dye on SCB, its bioremediation under SSF produces wastes biomass and which further utilized for enzymatic saccharification for biofuel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Effects of cutting orientation in poplar wood biomass size reduction on enzymatic hydrolysis sugar yield.

    PubMed

    Zhang, Meng; Ju, Xiaohui; Song, Xiaoxu; Zhang, Xiao; Pei, Z J; Wang, Donghai

    2015-10-01

    The aim of this study was to understand how cutting orientation in poplar wood biomass size reduction affects enzymatic hydrolysis sugar yield of wood particles. A metal cutting (milling) machine was used to produce poplar wood particles from three cutting orientations. Results showed that cutting orientation significantly affected enzymatic hydrolysis sugar yield of wood particles. In this study, size reduction from the optimum cutting orientation produced 50% more sugars than the other two cutting orientations. Particles from the cutting orientation with the highest sugar yield had a large enzyme accessible area (125 mg orange dye/g biomass, as evaluated by Simons' stain procedure) and low crystallinity (50% crystallinity index, as calculated by the Segal method). Furthermore, small particle size did not necessarily lead to improvement in enzymatic digestibility. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Enhanced enzymatic hydrolysis and structural features of corn stover by FeCl3 pretreatment.

    PubMed

    Liu, Li; Sun, Junshe; Li, Min; Wang, Shuhao; Pei, Haisheng; Zhang, Jingsheng

    2009-12-01

    Corn stover was pretreated with FeCl(3) to remove almost all of the hemicellulose present and then hydrolyzed with cellulase and beta-glucosidase to produce glucose. Enzymatic hydrolysis of corn stover that had been pretreated with FeCl(3) at 160 degrees C for 20 min resulted in an optimum yield of 98.0%. This yield was significantly higher than that of untreated corn stover (22.8%). FeCl(3) pretreatment apparently damaged the surface of corn stover and significantly increased the enzymatic digestibility, as evidenced by SEM and XRD analysis data. FTIR analysis indicated that FeCl(3) pretreatment could disrupt almost all the ether linkages and some ester linkages between lignin and carbohydrates but had no effect on delignification. The FeCl(3) pretreatment technique, as a novel pretreatment method, enhances enzymatic hydrolysis of lignocellulosic biomass by destructing chemical composition and altering structural features.

  5. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    DOE PAGES

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; ...

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and themore » DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.« less

  6. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    SciTech Connect

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; Huang, Fang; Pu, Yunqiao; Ragauskas, Arthur J.

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and the DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.

  7. Mechanistic modeling of enzymatic hydrolysis of cellulose integrating substrate morphology and cocktail composition.

    PubMed

    Huron, Maïté; Hudebine, Damien; Lopes Ferreira, Nicolas; Lachenal, Dominique

    2016-05-01

    A mechanistic model of enzymatic hydrolysis taking into account the morphology of the cellulosic particles and its evolution with time was developed. The individual behavior of the main enzymes involved in the reaction (cellobiohydrolases, endoglucanases, and β-glucosidases), as well as synergy effects, were also included. A large panel of experimental tests was done to fit and validate the model. This database included different enzymes mixtures and operating conditions and allowed to determine and compare with accuracy the adsorption and kinetic parameters of the different enzymes. Model predictions on short hydrolysis times were very satisfactory. On longer times, a deactivation constant was added to represent the hydrolysis slowdown. The model also allowed to predict the impact of enzymes ratios and initial substrate parameters (chain length distribution, polymerization degree) on hydrolysis, and to follow the evolution of these parameters with time. This model revealed general trends on the impact of cellulose morphology on hydrolysis. It is a useful tool to better understand the mechanisms involved in enzymatic hydrolysis of cellulose and to determine optimal cellulolytic cocktails for process design.

  8. Kinetics of enzymatic high-solid hydrolysis of lignocellulosic biomass studied by calorimetry.

    PubMed

    Olsen, Søren N; Lumby, Erik; McFarland, Kc; Borch, Kim; Westh, Peter

    2011-03-01

    Enzymatic hydrolysis of high-solid biomass (>10% w/w dry mass) has become increasingly important as a key step in the production of second-generation bioethanol. To this end, development of quantitative real-time assays is desirable both for empirical optimization and for detailed kinetic analysis. In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis rate with a detection limit of about 500 pmol glucose s(-1). Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose-response experiments with a typical cellulase cocktail enabled a multidimensional analysis of the interrelationships of enzyme load and the rate, time, and extent of the reaction. The results suggest that the hydrolysis rate of pretreated corn stover is limited initially by available attack points on the substrate surface (<10% conversion) but becomes proportional to enzyme dosage (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear to be the source of reduced hydrolysis rate over time.

  9. Physicochemical structural changes of poplar and switchgrass during biomass pretreatment and enzymatic hydrolysis

    SciTech Connect

    Meng, Xianzhi; Sun, Qining; Kosa, Matyas; Huang, Fang; Pu, Yunqiao; Ragauskas, Arthur J.

    2016-07-27

    Converting lignocellulosics to simple sugars for second generation bioethanol is complicated due to biomass recalcitrance, and it requires a pretreatment stage prior to enzymatic hydrolysis. In this study, native, pretreated (acid and alkaline) and partially hydrolyzed poplar and switchgrass were characterized by using Simons’ staining for cellulose accessibility, GPC for degree of polymerization (DP), and FTIR for chemical structure of plant cell wall. The susceptibility of the pretreated biomass to enzymatic hydrolysis could not be easily predicted from differences in cellulose DP and accessibility. During hydrolysis, the most significant DP reduction occurred at the very beginning of hydrolysis, and the DP began to decrease at a significantly slower rate after this initial period, suggesting an existence of a synergistic action of endo- and exoglucanases that contribute to the occurrence of a “peeling off” mechanism. Cellulose accessibility was found to be increased at the beginning of hydrolysis, after reaching a maximum value then started to decrease. In conclusion, the fresh enzyme restart hydrolysis experiment along with the accessibility data indicated that the factors associated with the nature of enzyme such as irreversible nonspecific binding of cellulases by lignin and steric hindrance of enzymes should be responsible for the gradual slowing down of the reaction rate.

  10. Scale-up and integration of alkaline hydrogen peroxide pretreatment, enzymatic hydrolysis, and ethanolic fermentation.

    PubMed

    Banerjee, Goutami; Car, Suzana; Liu, Tongjun; Williams, Daniel L; Meza, Sarynna López; Walton, Jonathan D; Hodge, David B

    2012-04-01

    Alkaline hydrogen peroxide (AHP) has several attractive features as a pretreatment in the lignocellulosic biomass-to-ethanol pipeline. Here, the feasibility of scaling-up the AHP process and integrating it with enzymatic hydrolysis and fermentation was studied. Corn stover (1 kg) was subjected to AHP pretreatment, hydrolyzed enzymatically, and the resulting sugars fermented to ethanol. The AHP pretreatment was performed at 0.125 g H(2) O(2) /g biomass, 22°C, and atmospheric pressure for 48 h with periodic pH readjustment. The enzymatic hydrolysis was performed in the same reactor following pH neutralization of the biomass slurry and without washing. After 48 h, glucose and xylose yields were 75% and 71% of the theoretical maximum. Sterility was maintained during pretreatment and enzymatic hydrolysis without the use of antibiotics. During fermentation using a glucose- and xylose-utilizing strain of Saccharomyces cerevisiae, all of the Glc and 67% of the Xyl were consumed in 120 h. The final ethanol titer was 13.7 g/L. Treatment of the enzymatic hydrolysate with activated carbon prior to fermentation had little effect on Glc fermentation but markedly improved utilization of Xyl, presumably due to the removal of soluble aromatic inhibitors. The results indicate that AHP is readily scalable and can be integrated with enzyme hydrolysis and fermentation. Compared to other leading pretreatments for lignocellulosic biomass, AHP has potential advantages with regard to capital costs, process simplicity, feedstock handling, and compatibility with enzymatic deconstruction and fermentation. Biotechnol. Bioeng. 2012; 109:922-931. © 2011 Wiley Periodicals, Inc. Copyright © 2011 Wiley Periodicals, Inc.

  11. Enzymatic hydrolysis of oleuropein from Olea europea (olive) leaf extract and antioxidant activities.

    PubMed

    Yuan, Jiao-Jiao; Wang, Cheng-Zhang; Ye, Jian-Zhong; Tao, Ran; Zhang, Yu-Si

    2015-02-11

    Oleuropein (OE), the main polyphenol in olive leaf extract, is likely to decompose into hydroxytyrosol (HT) and elenolic acid under the action of light, acid, base, high temperature. In the enzymatic process, the content of OE in olive leaf extract and enzyme are key factors that affect the yield of HT. A selective enzyme was screened from among 10 enzymes with a high OE degradation rate. A single factor (pH, temperature, time, enzyme quantity) optimization process and a Box-Behnken design were studied for the enzymatic hydrolysis of 81.04% OE olive leaf extract. Additionally, enzymatic hydrolysis results with different substrates (38.6% and 81.04% OE) were compared and the DPPH antioxidant properties were also evaluated. The result showed that the performance of hydrolysis treatments was best using hemicellulase as a bio-catalyst, and the high purity of OE in olive extract was beneficial to biotransform OE into HT. The optimal enzymatic conditions for achieving a maximal yield of HT content obtained by the regression were as follows: pH 5, temperature 55 °C and enzyme quantity 55 mg. The experimental result was 11.31% ± 0.15%, and the degradation rate of OE was 98.54%. From the present investigation of the antioxidant activity determined by the DPPH method, the phenol content and radical scavenging effect were both decreased after enzymatic hydrolysis by hemicellulase. However, a high antioxidant activity of the ethyl acetate extract enzymatic hydrolysate (IC50 = 41.82 μg/mL) was demonstated. The results presented in this work suggested that hemicellulase has promising and attractive properties for industrial production of HT, and indicated that HT might be a valuable biological component for use in pharmaceutical products and functional foods.

  12. Sediments in coffee extracts: Composition and control by enzymatic hydrolysis.

    PubMed

    Delgado, P A; Vignoli, J A; Siika-Aho, M; Franco, T T

    2008-09-01

    The water-insolubility of some coffee extract components is one of the major limitations in the production of instant coffee. In this work, fractions from coffee extracts and sediments were prepared, and their chemical composition determined. Based on the carbohydrate analysis, galactomannan was found to be the main polysaccharide component of the insoluble fractions and probably responsible for sediment formation. The suitability of twelve commercial enzymes for the hydrolysis of the insoluble fractions was investigated. Pectinase 444L was the most effective enzyme in releasing sugars, mainly mannose and galactose, from these substrates. Biopectinase CCM, Rohapect B1L, Pectinase 444L and Galactomannanase ACH were found to be the most effective enzymes for reducing the sediment of coffee extracts. The highest sediment reduction was obtained using Rohapect B1L and Galactomannanase ACH, at enzyme concentrations of 0.3 and 0.1mg protein/g substrate, respectively. Copyright © 2008 Elsevier Ltd. All rights reserved.

  13. Enzymatic hydrolysis of microcrystalline cellulose in concentrated seawater.

    PubMed

    Grande, Philipp M; de María, Pablo Domínguez

    2012-01-01

    This communication explores the use of seawater (1X) and concentrated seawater (2X and 4X) as reaction media for the enzyme-catalyzed depolymerization of cellulose. The commercially available Accellerase-1500® - a "cocktail" of different glycosidases - is able to depolymerize several amorphous celluloses and microcrystalline cellulose Avicel® in these reaction media, at slightly lower rates (ca. 90%) than those observed when reactions are performed in pure citrate buffer (control reactions). Remarkably, at concentrated seawater effluents enzymes also display significant rates of cellulose hydrolysis. Considering the expected increasing shortages in accessibility to fresh drinkable water, the herein-reported concept may provide novel inspiring leads for a smart use of resources in an environmentally-friendly and efficient manner, and for the genetic development of cellulases highly active and stable in concentrated seawater solutions.

  14. Influence of homogenization treatment on physicochemical properties and enzymatic hydrolysis rate of pure cellulose fibers.

    PubMed

    Jacquet, N; Vanderghem, C; Danthine, S; Blecker, C; Paquot, M

    2013-02-01

    The aim of this study is to compare the effect of different homogenization treatments on the physicochemical properties and the hydrolysis rate of a pure bleached cellulose. Results obtained show that homogenization treatments improve the enzymatic hydrolysis rate of the cellulose fibers by 25 to 100 %, depending of the homogenization treatment applied. Characterization of the samples showed also that homogenization had an impact on some physicochemical properties of the cellulose. For moderate treatment intensities (pressure below 500 b and degree of homogenization below 25), an increase of water retention values (WRV) that correlated to the increase of the hydrolysis rate was highlighted. Result also showed that the overall crystallinity of the cellulose properties appeared not to be impacted by the homogenization treatment. For higher treatment intensities, homogenized cellulose samples developed a stable tridimentional network that contributes to decrease cellulase mobility and slowdown the hydrolysis process.

  15. Comparison of aqueous ammonia and dilute acid pretreatment of bamboo fractions: Structure properties and enzymatic hydrolysis.

    PubMed

    Xin, Donglin; Yang, Zhong; Liu, Feng; Xu, Xueru; Zhang, Junhua

    2015-01-01

    The effect of two pretreatments methods, aqueous ammonia (SAA) and dilute acid (DA), on the chemical compositions, cellulose crystallinity, morphologic change, and enzymatic hydrolysis of bamboo fractions (bamboo yellow, timber, green, and knot) was compared. Bamboo fractions with SAA pretreatment had better hydrolysability than those with DA pretreatment. High crystallinity index resulted in low hydrolysis yield in the conversion of SAA pretreated bamboo fractions, not DA pretreated fractions. The increase of cellulase loading had modestly positive effect in the hydrolysis of both SAA and DA pretreated bamboo fractions, while supplement of xylanase significantly increased the hydrolysis of the pretreated bamboo fractions, especially after SAA pretreatment. The results indicated that SAA pretreatment was more effective than DA pretreatment in conversion of bamboo fractions, and supplementation of xylanase was necessary in effective conversion of the SAA pretreated fractions into fermentable sugars. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Acid and enzymatic hydrolysis of pretreated cellulosic materials as an analytical tool

    SciTech Connect

    Ladisch, C.M.; Chiasson, C.M.; Tsao, G.T.

    1982-07-01

    A rapid and accurate procedure for the quantitative analysis of cellulose in textiles based on acid and enzymatic hydrolysis was investigated. Total hydrolysis was achieved by a two-step procedure: the cellulose in the sample was first dissolved in cadoxen and then reprecipitated. The material, thus pretreated, was then hydrolyzed with acid or enzyme catalytic agents. Hydrolysis products were detected and quantified by colorimetric, enzymic, and liquid chromatographic methods of analysis. Samples examined included cotton, rayon, Avicel, CF-11, and cotton/polyester blends. The specificity of the enzyme hydrolysis method allowed analysis of raw cotton without prior purification. Results of the analyses were compared to those obtained by existing methods of analysis.

  17. Pseudo-lignin formation and its impact on enzymatic hydrolysis.

    PubMed

    Hu, Fan; Jung, Seokwon; Ragauskas, Arthur

    2012-08-01

    Pseudo-lignin, which can be broadly defined as aromatic material that yields a positive Klason lignin value and is not derived from native lignin, has been recently reported to form during the dilute acid pretreatment of poplar holocellulose. To investigate the chemistry of pseudo-lignin formation, GPC, FT-IR and 13C NMR were utilized to characterize pseudo-lignin extracted from dilute-acid pretreated α-cellulose and holocellulose. The results showed that pseudo-lignin consisting of carbonyl, carboxylic, aromatic and aliphatic structures was produced from dilute acid pretreated cellulose and hemicellulose. Pseudo-lignin extracted from holocellulose pretreated at different conditions had similar molecular weights (Mn∼1000 g/mol; Mw∼5000 g/mol) and structural features (carbonyl, carboxylic, aromatic and methoxy structures). These characterizations have provided the pseudo-lignin formation mechanisms during pretreatment. The presence and structure of pseudo-lignin is important since pseudo-lignin decreases the enzymatic conversion.

  18. Effect of pretreatment on the enzymatic hydrolysis of kitchen waste for xanthan production.

    PubMed

    Li, Panyu; Zeng, Yu; Xie, Yi; Li, Xiang; Kang, Yan; Wang, Yabo; Xie, Tonghui; Zhang, Yongkui

    2017-01-01

    The study was carried out to gain insight into the effect of pretreatment on enzymatic hydrolysis of kitchen waste (KW) for xanthan fermentation. Herein, various pretreatments were applied and it was found that chemical pretreatment had positive effect on the following enzymatic or overall hydrolysis process. The highest reducing sugar concentration was obtained as 51.87g/L from 2% HCl (90°C) pretreated sample, while the Kjeldahl nitrogen (KDN) concentration was 7.79g/L. Kinetic study showed that first order kinetic model was suitable to describe the enzymatic hydrolysis process. The obtained kitchen waste hydrolysate (KWH) was successfully applied for xanthan fermentation. Xanthan concentration reached 4.09-6.46g/L when KWH with 2% HCl (90°C) pretreatment was applied as medium. In comparison, a xanthan concentration of 3.25-5.57g/L was obtained from KWH without pretreatment. Therefore, pretreatment of KW using diluted acid is favorable for the overall hydrolysis process and effective for xanthan fermentation.

  19. Evaluation of pretreatment with Pleurotus ostreatus for enzymatic hydrolysis of rice straw.

    PubMed

    Taniguchi, Masayuki; Suzuki, Hiroyuki; Watanabe, Daisuke; Sakai, Kenji; Hoshino, Kazuhiro; Tanaka, Takaaki

    2005-12-01

    The effects of biological pretreatment of rice straw using four white-rot fungi (Phanerochaete chrysosporium, Trametes versicolor, Ceriporiopsis subvermispora, and Pleurotus ostreatus) were evaluated on the basis of quantitative and structural changes in the components of the pretreated rice straw as well as susceptibility to enzymatic hydrolysis. Of these white-rot fungi, P. ostreatus selectively degraded the lignin fraction of rice straw rather than the holocellulose component. When rice straw (water content of 60%) was pretreated with P. ostreatus for 60 d, the total weight loss and the degree of Klason lignin degraded were 25% and 41%, respectively. After the pretreatment, the residual amounts of cellulose and hemicellulose were 83% and 52% of those in untreated rice straw, respectively. By enzymatic hydrolysis with a commercial cellulase preparation for 48 h, 52% holocellulose and 44% cellulose in the pretreated rice straw were solubilized. The net sugar yields based on the amounts of holocellulose and cellulose of untreated rice straw were 33% for total soluble sugar from holocellulose and 32% for glucose from cellulose. The SEM observations showed that the increase in susceptibility of rice straw to enzymatic hydrolysis by pretreatment with P. ostreatus is caused by partial degradation of the lignin seal. When the content of Klason lignin was less than 15% of the total weight of the pretreated straw, enhanced degrees of enzymatic solubilization of holocellulose and cellulose fractions were observed as the content of Klason lignin decreased.

  20. On a novel mechanistic model for simultaneous enzymatic hydrolysis of cellulose and hemicellulose considering morphology.

    PubMed

    Zhang, Yang; Xu, Bingqian; Zhou, Wen

    2014-09-01

    We develop a novel and general modeling framework for enzymatic hydrolysis of cellulose and hemicellulose simultaneously. Our mechanistic model, for the first time, takes into consideration explicitly the time evolution of morphologies of intertwining cellulose and hemicelluloses within substrate during enzymatic hydrolysis. This morphology evolution is driven by hydrolytic chain fragmentation and solubilization, which is, in return, profoundly affected by the substrate morphology. We represent the substrate morphology as a randomly distributed smallest accessible compartments (SACs) which are described by geometric functions to track total volume and exposed surface substrate materials, including both cellulose and hemicelluloses. Our morphology-plus-kinetics approach then couple the time-dependent morphology with chain fragmentation and solubilization resulted from enzymatic reactions between various bonds in cellulose and hemicelluloses and a mixture (i.e., endo-, exo-, and oligomer- acting) of cellulases and hemicellulases. In addition, we propose an advanced and generalized site concentration formalism that considers different polysaccharide chain types and different monomer unit types on chains. The resulting ODE system has a substantially reduced size compared to conventional chain concentration formalism. We present numerical simulation results under real enzymatic hydrolysis experimental conditions from literature. The comparisons between the simulation results and the experiment measurements demonstrate effectiveness and wide applicability of the proposed mechanistic model.

  1. Effect of phosphoric acid pretreatment on enzymatic hydrolysis of microcrystalline cellulose.

    PubMed

    Zhang, Juanhua; Zhang, Beixiao; Zhang, Jingqiang; Lin, Lu; Liu, Shijie; Ouyang, Pingkai

    2010-01-01

    Microcrystalline cellulose (MCC) was pretreated with phosphoric acid at 323K for 10h. X-ray diffraction (XRD) and Atomic Force Microscope (AFM) analyses revealed that the fiber surface morphology of pretreated MCC (P-MCC) were uneven and rough with the crystalline diffraction peaks of P-MCC decreased to a distinct range. The X-ray Photoelectron Spectroscopy (XPS) analysis showed that the uneven and rough surface of P-MCC could enhance the adsorption of cellulose to the molecular surface of cellulose, which is one of the key factors affecting enzymatic hydrolysis of cellulose. A reversible first order kinetics was employed to describe the adsorption kinetics of cellulase to MCC and P-MCC, and the adsorption rate constants of MCC and P-MCC were found to be 0.016, 0.024, 0.041, and 0.095, 0.149, 0.218min(-1), respectively at 278K, 293K and 308K. The activation energies of MCC and P-MCC hydrolysis reactions were found to be 22.257 and 19.721kJ mol(-1). The major hydrolysis products of MCC and P-MCC were cellobiose and glucose. Hydrolysis of MCC for 120h resulted in yields of glucose (7.21%), cellobiose (13.16%) and total sugars (20.37%). However, after the pretreatment with phosphoric acid, the corresponding sugar yields resulted from enzymatic hydrolysis of P-MCC were increased to 24.10%, 41.42%, and 65.52%; respectively, which were 3.34, 3.15, and 3.22 times of the sugars yields from enzymatic hydrolysis of MCC.

  2. Effects of organosolv and ammonia pretreatments on lignin properties and its inhibition for enzymatic hydrolysis

    DOE PAGES

    Yoo, Chang Geun; Li, Mi; Meng, Xianzhi; ...

    2017-04-05

    Lignin offers structural support and protection for plant cell walls; but, it also contributes to biomass recalcitrance and the costs of biofuel production via the biological pathway. Organosolv and ammonia pretreatments have been developed to reduce biomass recalcitrance and improve sugar release performance during enzymatic hydrolysis. It is believed that lignin properties are related to its inhibition on enzymatic hydrolysis; therefore, understanding the characteristics of lignin is a key for effective biomass conversion to biofuels. In this study, an organosolv pretreatment using 60% ethanol with 1.25% H2SO4 significantly deconstructed poplar lignin and reduced its molecular weights due to the cleavagemore » of lignin inter-unit linkages. The organosolv pretreatment increased the contents of phenolic OH units and the lignin residue showed a high cellulase maximum adsorption capacity. Ammonia pretreatment with 5% ammonium hydroxide was not as effective as organosolv pretreatment on lignin deconstruction. Organosolv lignin residue had lower lignin S/G ratio than the untreated one. Furthermore, when compared to the organosolv lignin residue and untreated lignin, ammonia lignin residue had a higher cellulase adsorption affinity. In addition, the effects of lignin on cellulose hydrolysis was investigated and the results suggested that the presence of lignin with cellulose substrates reduced cellulose hydrolysis, and its inhibitory effect was primarily determined by the lignin properties after each pretreatment. The organosolv pretreatment resulted in a slightly lower cellulase binding strength (249.7 mL g-1) on poplar lignin than that on untreated samples (261.1 mL g-1), while ammonia lignin residue showed a higher cellulase binding strength (402.8 mL g-1) and had more significant inhibition effect on cellulose hydrolysis. Our results demonstrated that the binding strength significantly affected the lignin-derived inhibition on enzymatic hydrolysis of cellulose in

  3. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis.

    PubMed

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M; Park, Sunkyu; Kim, Seong H

    2015-10-14

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples--Avicel, bleached softwood, and bacterial cellulose--to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

  4. Role of supramolecular cellulose structures in enzymatic hydrolysis of plant cell walls.

    PubMed

    Thygesen, Lisbeth Garbrecht; Hidayat, Budi Juliman; Johansen, Katja Salomon; Felby, Claus

    2011-08-01

    The study of biomass deconstruction by enzymatic hydrolysis has hitherto not focussed on the importance of supramolecular structures of cellulose. In lignocellulose fibres, regions with a different organisation of the microfibrils are present. These regions are called dislocations or slip planes and they are known to be more susceptible to various forms of degradation such as acid hydrolysis. Traditionally the cellulose within these regions has been assumed to be amorphous, but in this study it is shown by use of polarized light microscopy that dislocations are birefringent. This indicates that they have a crystalline organisation. Dislocations may be entry points for endoglucanases. Using a fluorescent labelled endoglucanase combined with confocal fluorescence microscopy, it is shown that the enzyme selectively binds to dislocations during the initial phase of the hydrolysis. Using a commercial cellulase mixture on hydrothermally treated wheat straw, it was found that the fibres were cut into segments corresponding to the sections between the dislocations initially present, as has previously been observed for acid hydrolysis of softwood pulps. The results indicate that dislocations are important during the initial part of enzymatic hydrolysis of cellulose. The implications of this phenomenon have not yet been recognized or explored within cellulosic biofuels.

  5. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    NASA Astrophysics Data System (ADS)

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; Park, Sunkyu; Kim, Seong H.

    2015-10-01

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

  6. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    PubMed Central

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; Park, Sunkyu; Kim, Seong H.

    2015-01-01

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component. PMID:26463274

  7. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    SciTech Connect

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; Park, Sunkyu; Kim, Seong H.

    2015-10-14

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. Moreover, it was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

  8. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    DOE PAGES

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; ...

    2015-10-14

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlatemore » with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. Moreover, it was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.« less

  9. Progressive structural changes of Avicel, bleached softwood, and bacterial cellulose during enzymatic hydrolysis

    SciTech Connect

    Kafle, Kabindra; Shin, Heenae; Lee, Christopher M.; Park, Sunkyu; Kim, Seong H.

    2015-10-14

    A comprehensive picture of structural changes of cellulosic biomass during enzymatic hydrolysis is essential for a better understanding of enzymatic actions and development of more efficient enzymes. In this study, a suite of analytical techniques including sum frequency generation (SFG) spectroscopy, infrared (IR) spectroscopy, x-ray diffraction (XRD), and x-ray photoelectron spectroscopy (XPS) were employed for lignin-free model biomass samples—Avicel, bleached softwood, and bacterial cellulose—to find correlations between the decrease in hydrolysis rate over time and the structural or chemical changes of biomass during the hydrolysis reaction. The results showed that the decrease in hydrolysis rate over time appears to correlate with the irreversible deposition of non-cellulosic species (either reaction side products or denatured enzymes, or both) on the cellulosic substrate surface. The crystallinity, degree of polymerization, and meso-scale packing of cellulose do not seem to positively correlate with the decrease in hydrolysis rate observed for all three substrates tested in this study. It was also found that the cellulose Iα component of the bacterial cellulose is preferentially hydrolyzed by the enzyme than the cellulose Iβ component.

  10. Effects of structural features of cotton cellulose on enzymatic hydrolysis. [Gamma radiation

    SciTech Connect

    Focher, B.; Cattaneo, M.; Beltrame, P.L.; Carniti, P.

    1981-06-01

    Textile cotton wastes were treated with ..gamma.. rays and 18% NaOH and 70% ZnCl/sub 2/ solutions and were subjected to enzymatic hydrolysis. The untreated and treated samples were characterized both before and after hydrolysis by means of parameters concerning molecular structure (degree of polymerization), supermolecular structure (x-ray diffraction), accessibility, and reactivity (moisture regain, enzyme adsorption, and solubility in FeTNa). These parameters were correlated to kinetic parameters of the hydrolysis reaction. The V/sub max/ and K/sub m/ values were evaluated from Lineweaver-Burk plots at different temperatures. The V/sub max//K/sub m/ ratio, analogous to the specificity constant, proved to be less sensitive to experimental errors and more suitable for a comparison of the kinetic behavior of the samples. The modifications of both supermolecular structure and morphology of cellulose were of primary importance to attain high yields and rates of hydrolysis. Furthermore, the structural and morphologic parameters chosen to characterize the samples can be correlated to the kinetic parameters of enzymatic hydrolysis, in particular to K/sub m/ values.

  11. Development of a process for the production of L-amino-acids concentrates from microalgae by enzymatic hydrolysis.

    PubMed

    Romero García, J M; Acién Fernández, F G; Fernández Sevilla, J M

    2012-05-01

    A process for the production of l-amino-acids concentrates from microalgae biomass by enzymatic hydrolysis has been developed. The process includes pre-treatment for cell-disruption, enzymatic hydrolysis and final separation by centrifugation. Thermal and mechanical cell-disruption methods have been tested, selecting mechanical disruption using bead milling for 30 min. The enzymatic hydrolysis was done using the commercial enzymes Alcalase and Flavourzyme. Maximum hydrolysis was obtained for biomass concentrations under 270 g/l and previous additional treatment with Viscozyme, reaching a 42% hydrolysis. Repeated reaction steps increased the hydrolysis from 42% (4h) with a single step to 59% (8h) after two successive steps. Further increase of the number of steps had a meagre impact on the global yield. The process widens the portfolio of products that can be obtained from microalgae biomass and is a new possibility to enhance the economic viability of microalgae-based biofuels production processes.

  12. The slowdown of the endoglucanase Trichoderma reesei Cel5A-catalyzed cellulose hydrolysis is related to its initial activity.

    PubMed

    Shu, Zhiyu; Wang, Yefei; An, Liaoyuan; Yao, Lishan

    2014-12-09

    One important feature of hydrolysis of cellulose by cellulases is that the reaction slows down quickly after it starts. In this work, we investigate the slowdown mechanism at the early stage of the reaction using endoglucanase Tr. Cel5A-catalyzed phosphate acid-swollen cellulose (PASC) hydrolysis as a model system. Specifically, we focus on the effect of enzyme adsorption on the reaction slowdown. Nineteen single mutations are introduced (with the assistance of molecular dynamics simulations) to perturb the enzyme PASC interaction, yielding the adsorption partitioning coefficient Kr that ranged from 0.12 to 0.39 L/g, compared to that of the wild type (0.26 L/g). Several residues, including T18, K26, Y26, H229, and T300, are demonstrated to be important for adsorption of the enzyme to PASC. The kinetic measurements show that the slowdown of the hydrolysis is not correlated with the adsorption quantified by the partitioning coefficient Kr but is anticorrelated with the initial activity. This result suggests that the mutants with higher activity are more prone to being trapped or deplete the most reactive substrate faster and the adsorption plays no apparent role in the reaction slowdown. The initial activity of Cel5A against PASC is correlated with the enzyme specific activity against a soluble substrate p-nitrophenyl cellobioside.

  13. Improved enzymatic hydrolysis of wheat straw by combined use of gamma ray and dilute acid for bioethanol production

    NASA Astrophysics Data System (ADS)

    Hyun Hong, Sung; Taek Lee, Jae; Lee, Sungbeom; Gon Wi, Seung; Ju Cho, Eun; Singh, Sudhir; Sik Lee, Seung; Yeoup Chung, Byung

    2014-01-01

    Pretreating wheat straw with a combination of dilute acid and gamma irradiation was performed in an attempt to enhance the enzymatic hydrolysis for bioethanol production. The glucose yield was significantly affected by combined pretreatment (3% sulfuric acid-gamma irradiation), compared with untreated wheat straw and individual pretreatment. The increasing enzymatic hydrolysis after combined pretreatment is resulting from decrease in crystallinity of cellulose, loss of hemicelluloses, and removal or modification of lignin. Therefore, combined pretreatment is one of the most effective methods for enhancing the enzymatic hydrolysis of wheat straw biomass.

  14. High temperature aqueous ammonia pretreatment and post-washing enhance the high solids enzymatic hydrolysis of corn stover.

    PubMed

    Qin, Lei; Liu, Zhi-Hua; Jin, Mingjie; Li, Bing-Zhi; Yuan, Ying-Jin

    2013-10-01

    Aqueous ammonia pretreatment was optimized and the limiting factors in high solids enzymatic hydrolysis were assessed. The recommended pretreatment condition to achieve high enzymatic yield was: 180 °C, 20% (w/w) ammonia, 30 min, and 20% solids content. FT-IR and GC-MS results indicated that most of the lignin was degraded to soluble fragments after pretreatment. The pretreated solids after post-washing showed higher enzymatic digestibility at high solids loading than that without washing. The washed solids required lower cellulase and xylanase dosage than unwashed solids to achieve high sugar yield. Enzymatic conversions were declined with the increased solids loading of pretreated solids, pretreated-washed solids, and filter papers. The results indicated that solids loading in enzymatic hydrolysis was an important factor affecting sugar yield. The increasing concentration of glucose and ligno-phenolics mainly inhibited the enzymatic hydrolysis of aqueous ammonia pretreated corn stover. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Enzymatic Hydrolysis of Cellulosic Materials to Fermentable Sugars for the Production of Ethanol

    DTIC Science & Technology

    1980-10-12

    and properties of the·cellulase enzyme complex from Trichoderma reesei strains presently available are similar regardless of the strain or grmqth s...feasibility ·.;f using such a process .. 2. The MCG77 strain of Trichoderma reesei produced more sugar on NEP200 than both QM9414 and C30 at three different...Saccharification Potential of Trichoderma reesei Cellulase (Reference 1) Huch recent effort at Natick and elsewhere has been directed to reduction of the

  16. Pretreatment of garden biomass by alkali-assisted ultrasonication: effects on enzymatic hydrolysis and ultrastructural changes

    PubMed Central

    2014-01-01

    The present investigation aims at studying the effectiveness of alkali-assisted ultrasonication on pretreatment of garden biomass (GB). Dry and powdered GB suspended in 1% NaOH was ultrasonicated for 15, 30 and 60 minutes at a frequency of 25 KHZ. The mode of action and effectiveness of alkali-assisted ultrasonication on GB was established through microscopic, scanning electron microscopic and X-ray diffraction studies. A perusal of results showed that alkali-assisted ultrasonication led to fibrillation of GB which ultimately facilitated enzymatic hydrolysis. The results also indicated that alkali-assisted ultrasonication is an efficient means of pretreatment of GB at moderate (45-50°C) working temperature and low (1%) concentration of alkali. The yield of reducing sugar after enzymatic hydrolysis increased almost six times as compared to control due to alkali-assisted ultrasonication. PMID:24843790

  17. Pretreatment of olive tree biomass with FeCl3 prior enzymatic hydrolysis.

    PubMed

    López-Linares, Juan C; Romero, Inmaculada; Moya, Manuel; Cara, Cristóbal; Ruiz, Encarnación; Castro, Eulogio

    2013-01-01

    Olive tree biomass (OTB) is an agricultural residue which can be used as raw material for bioethanol production. OTB was pretreated with 0.05-0.275 M FeCl(3) solutions at 120-180 °C for 0-30 min. Enzymatic hydrolysis yields were used for assessing pretreatment performance. Optimum FeCl(3) pretreatment conditions were found to be 152.6 °C, 0.26 M FeCl(3) for 30 min. Under such conditions, 100% of hemicellulose was removed, and enzymatic hydrolysis of pretreated solids resulted in a yield of 36.6g glucose/100g of glucose in the raw material. Hemicellulosic sugar recovery in the prehydrolysate was 63.2%. Results compare well with those obtained by other pretreatment strategies on the same raw material, confirming FeCl(3) solutions as a new, feasible approach for bioethanol production. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Enzymatic hydrolysis of quinizarin diester by lipase in silica nanoparticles investigated by fluorescence microscopy

    NASA Astrophysics Data System (ADS)

    Sabatini, Carolina A.; Gehlen, Marcelo H.

    2014-06-01

    The enzymatic hydrolysis of quinizarin diester in silica nanoparticle (NP) of 200 nm diameter is investigated by confocal fluorescence microscopy. The quinizarin diester substrate and the intermediate quinizarin monoester are non-fluorescent species and only the end product—quinizarin formed by enzymatic hydrolysis produces intense fluorescence of the silica NP. The enzyme activity of lipase adsorbed into silica NP was similar to that observed for lipase chemically bound to silica surface. In both situations, partial aggregation of the silica NP dispersed in thin film of polyvinylpyrrolidone was observed from fluorescence and scanning electron microscopy images. The fluorescence decay of the end product—quinizarin in silica NP was biexponential with decay times of 0.49 and 2.17 ns. These two decay times found are ascribed to quinizarin adsorbed in silica NP and dispersed in the surrounding medium, respectively.

  19. Pretreatment of garden biomass by alkali-assisted ultrasonication: effects on enzymatic hydrolysis and ultrastructural changes.

    PubMed

    Gabhane, Jagdish; William, Spm Prince; Vaidya, Atul Narayan; Anand, Duraisamy; Wate, Satish

    2014-01-01

    The present investigation aims at studying the effectiveness of alkali-assisted ultrasonication on pretreatment of garden biomass (GB). Dry and powdered GB suspended in 1% NaOH was ultrasonicated for 15, 30 and 60 minutes at a frequency of 25 KHZ. The mode of action and effectiveness of alkali-assisted ultrasonication on GB was established through microscopic, scanning electron microscopic and X-ray diffraction studies. A perusal of results showed that alkali-assisted ultrasonication led to fibrillation of GB which ultimately facilitated enzymatic hydrolysis. The results also indicated that alkali-assisted ultrasonication is an efficient means of pretreatment of GB at moderate (45-50°C) working temperature and low (1%) concentration of alkali. The yield of reducing sugar after enzymatic hydrolysis increased almost six times as compared to control due to alkali-assisted ultrasonication.

  20. Significantly enhancing enzymatic hydrolysis of rice straw after pretreatment using renewable ionic liquid-water mixtures.

    PubMed

    Hou, Xue-Dan; Li, Ning; Zong, Min-Hua

    2013-05-01

    Pretreatment of rice straw by using renewable cholinium lysine ionic liquid ([Ch][Lys] IL)-water mixtures and subsequent enzymatic hydrolysis of the residues were conducted in this work. There is a clear correlation between the delignification capacity of the pretreatment solvent and its basicity. After pretreatment, surface area and pore volume of rice straw increased significantly, which substantially improved polysaccharides accessibility to enzymes and thus enhanced polysaccharides digestion. By carefully controlling the pretreatment severity (IL content, temperature and duration), loss of readily extractable xylan could be minimized. The sugar yields of 81% for glucose and 48% for xylose were achieved in the enzymatic hydrolysis of rice straw after pretreatment with 20% [Ch][Lys]-water mixture at 90 °C for 1 h. This pretreatment process is highly promising for industrial application because of high sugar yields, low energy input, short pretreatment time, and being environmentally benign and highly tolerant to moisture. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Phosphoric acid pretreatment of Achyranthes aspera and Sida acuta weed biomass to improve enzymatic hydrolysis.

    PubMed

    Siripong, Premjet; Duangporn, Premjet; Takata, Eri; Tsutsumi, Yuji

    2016-03-01

    Achyranthes aspera and Sida acuta, two types of weed biomass are abundant and waste in Thailand. We focus on them as novel feedstock for bio-ethanol production because they contain high-cellulose content (45.9% and 46.9%, respectively) and unutilized material. Phosphoric acid (70%, 75%, and 80%) was employed for the pretreatment to improve by enzymatic hydrolysis. The pretreatment process removed most of the xylan and a part of the lignin from the weeds, while most of the glucan remained. The cellulose conversion to glucose was greater for pretreated A. aspera (86.2 ± 0.3%) than that of the pretreated S. acuta (82.2 ± 1.1%). Thus, the removal of hemicellulose significantly affected the efficiency of the enzymatic hydrolysis. The scanning electron microscopy images showed the exposed fibrous cellulose on the cell wall surface, and this substantial change of the surface structure contributed to improving the enzyme accessibility.

  2. Optimal operating policy of the ultrafiltration membrane bioreactor for enzymatic hydrolysis of cellulose

    SciTech Connect

    Lee, SeungGoo; Kim, HakSung . Dept. of Biotechnology)

    1993-09-05

    The dilution rate of an ultrafiltration membrane bioreactor in the enzymatic hydrolysis of cellulose was optimized using the kinetic model developed by Fan and Lee.' The sequence of optimal dilution rates was found to generally consist of an initial period of a minimal value (batch period), a subsequent period of maximum dilution rate, a period of a second batch, and a final period of a singular dilution rate. The effects of operating conditions, such as [beta]-glucosidase activity, operating time, maximum dilution rate, substrate feeding rate, and enzyme-to-substrate ratio on both the conversion yield and the sequence of optimal dilution rates were investigated. To evaluate the validity of kinetic model employed in this work, enzymatic hydrolysis was carried out using -cellulose as a substrate in the ultrafiltration membrane bioreactor. The experimental data were well consistent with the simulation results.

  3. Modification of chemical reactivity of enzymatic hydrolysis lignin by ultrasound treatment in dilute alkaline solutions.

    PubMed

    Ma, Zhuoming; Li, Shujun; Fang, Guizhen; Patil, Nikhil; Yan, Ning

    2016-12-01

    In this study, we have explored various ultrasound treatment conditions for structural modification of enzymatic hydrolysis lignin (EHL) for enhanced chemical reactivity. The key structural modifications were characterized by using a combination of analytical methods, including, Fourier Transform-Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ((1)H NMR), Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Folin-Ciocalteu (F-C) method. Chemical reactivity of the modified EHL samples was determined by both 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and their reactivity towards formaldehyde. It was observed that the modified EHL had a higher phenolic hydroxyl group content, a lower molecular weight, a higher reactivity towards formaldehyde, and a greater antioxidant property. The higher reactivity demonstrated by the samples after treatment suggesting that ultrasound is a promising method for modifying enzymatic hydrolysis lignin for value-added applications.

  4. Dual modification of starch via partial enzymatic hydrolysis in the granular state and subsequent hydroxypropylation.

    PubMed

    Karim, A A; Sufha, E H; Zaidul, I S M

    2008-11-26

    The effect of enzymatic pretreatment on the degree of corn and mung bean starch derivatization by propylene oxide was investigated. The starch was enzymatically treated in the granular state with a mixture of fungal alpha-amylase and glucoamylase at 35 degrees C for 16 h and then chemically modified to produce enzyme-hydrolyzed-hydroxypropyl (HP) starch. Partial enzyme hydrolysis of starch in the granular state appeared to enhance the subsequent hydroxypropylation, as judged from the significant increase in the molar substitution. A variable degree of granule modification was obtained after enzyme hydrolysis, and one of the determinants of the modification degree appeared to be the presence of natural pores in the granules. Enzyme-hydrolyzed-HP starch exhibited significantly different functional properties compared to hydroxypropyl starch prepared from untreated (native) starch. It is evident that the dual modification of starch using this approach provides a range of functional properties that can be customized for specific applications.

  5. High temperature dilute acid pretreatment of coastal Bermuda grass for enzymatic hydrolysis.

    PubMed

    Redding, Arthur P; Wang, Ziyu; Keshwani, Deepak R; Cheng, Jay J

    2011-01-01

    Dilute sulfuric acid was used to pretreat coastal Bermuda grass at high temperature prior to enzymatic hydrolysis. After both pretreatment and enzymatic hydrolysis processes, the highest yield of total sugars (combined xylose and glucose) was 97% of the theoretical value. The prehydrolyzate liquor was analyzed for inhibitory compounds (furfural, hydroxymethylfurfural (HMF)) in order to assess potential risk for inhibition during the following fermentation. Accounting for the formation of the inhibitory compounds, a pretreatment with 1.2% acid at 140 °C for 30 min with a total sugar yield of 94% of the theoretical value may be more favorable for fermentation. From this study, it can be concluded that dilute sulfuric acid pretreatment can be successfully applied to coastal Bermuda grass to achieve high yields of monomeric glucose and xylose with acceptable levels of inhibitory compound formation.

  6. Microwave-assisted pretreatment of cellulose in ionic liquid for accelerated enzymatic hydrolysis.

    PubMed

    Ha, Sung Ho; Mai, Ngoc Lan; An, Gwangmin; Koo, Yoon-Mo

    2011-01-01

    For increasing cellulose accessibility to the enzymatic attack, the pretreatment is a necessary step to alter some structural characteristics of cellulosic materials. As a new pretreatment method, microwave irradiation on cellulose dissolution pretreatment with ionic liquids (ILs) was investigated in this study. Microwave irradiation not only enhanced the solubility of cellulose in ILs but also significantly decreased the degree of polymerization of regenerated cellulose after IL dissolution pretreatment, resulting in significant improvement of cellulose hydrolysis. The rate of enzymatic hydrolysis of cotton cellulose was increased by at least 12-fold after IL dissolution pretreatment at 110 °C and by 50-fold after IL dissolution pretreatment with microwave irradiation. Our results demonstrate that cellulose pretreatment with ILs and microwave irradiation is a potential alternative method for the pretreatment of cellulosic materials.

  7. Kinetic study of enzymatic hydrolysis of acid-pretreated coconut coir

    NASA Astrophysics Data System (ADS)

    Fatmawati, Akbarningrum; Agustriyanto, Rudy

    2015-12-01

    Biomass waste utilization for biofuel production such as bioethanol, has become more prominent currently. Coconut coir is one of lignocellulosic food wastes, which is abundant in Indonesia. Bioethanol production from such materials consists of more than one step. Pretreatment and enzymatic hydrolysis is crucial steps to produce sugar which can then be fermented into bioethanol. In this research, ground coconut coir was pretreated using dilute sulfuric acid at 121°C. This pretreatment had increased the cellulose content and decreased the lignin content of coconut coir. The pretreated coconut coir was hydrolyzed using a mix of two commercial cellulase enzymes at pH of 4.8 and temperature of 50°C. The enzymatic hydrolysis was conducted at several initial coconut coir slurry concentrations (0.1-2 g/100 mL) and reaction times (2-72 hours). The reducing sugar concentration profiles had been produced and can be used to obtain reaction rates. The highest reducing sugar concentration obtained was 1,152.567 mg/L, which was produced at initial slurry concentration of 2 g/100 mL and 72 hours reaction time. In this paper, the reducing sugar concentrations were empirically modeled as a function of reaction time using power equations. Michaelis-Menten kinetic model for enzymatic hydrolysis reaction is adopted. The kinetic parameters of that model for sulfuric acid-pretreated coconut coir enzymatic hydrolysis had been obtained which are Vm of 3.587×104 mg/L.h, and KM of 130.6 mg/L.

  8. Enzymatic Hydrolysis of Cellulose to Glucose: A Report on the NATICK Program

    DTIC Science & Technology

    1981-09-01

    percent glucose syrups were produced from milled cellulose pulp demonstrating the possibility of a commercial process (1968). 7. Continuous production of...ENZYMATIC SACCHARIFICATION OF WASTE CELLULOSE I MUTATION PRETREATMENT I FERMENTATION SUBSTRATE + ENZYMES SACCHARIRCATION GLUCOSE + BY PRODUCTS YEAST FERM...interest in the role of enzymes in using cellulose for animal feed and as a source of hydrolysi; sugar. Ghose reported continuous production of 5% glucose

  9. The dual effects of Maillard reaction and enzymatic hydrolysis on the antioxidant activity of milk proteins.

    PubMed

    Oh, N S; Lee, H A; Lee, J Y; Joung, J Y; Lee, K B; Kim, Y; Lee, K W; Kim, S H

    2013-08-01

    The objective of this study was to determine the enhanced effects on the biological characteristics and antioxidant activity of milk proteins by the combination of the Maillard reaction and enzymatic hydrolysis. Maillard reaction products were obtained from milk protein preparations, such as whey protein concentrates and sodium caseinate with lactose, by heating at 55°C for 7 d in sodium phosphate buffer (pH 7.4). The Maillard reaction products, along with untreated milk proteins as controls, were hydrolyzed for 0 to 3h with commercial proteases Alcalase, Neutrase, Protamex, and Flavorzyme (Novozymes, Bagsværd, Denmark). The antioxidant activity of hydrolyzed Maillard reaction products was determined by reaction with 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, their 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity, and the ability to reduce ferric ions. Further characteristics were evaluated by the o-phthaldialdehyde method and sodium dodecyl sulfate-PAGE. The degree of hydrolysis gradually increased in a time-dependent manner, with the Alcalase-treated Maillard reaction products being the most highly hydrolyzed. Radical scavenging activities and reducing ability of hydrolyzed Maillard reaction products increased with increasing hydrolysis time. The combined products of enzymatic hydrolysis and Maillard reaction showed significantly greater antioxidant activity than did hydrolysates or Maillard reaction products alone. The hydrolyzed Maillard reaction products generated by Alcalase showed significantly higher antioxidant activity when compared with the other protease products and the antioxidant activity was higher for the whey protein concentrate groups than for the sodium caseinate groups. These findings indicate that Maillard reaction products, coupled with enzymatic hydrolysis, could act as potential antioxidants in the pharmaceutical, food, and dairy industries.

  10. Structural Changes of Lignin after Liquid Hot Water Pretreatment and Its Effect on the Enzymatic Hydrolysis.

    PubMed

    Wang, Wen; Zhuang, Xinshu; Yuan, Zhenhong; Qi, Wei; Yu, Qiang; Wang, Qiong

    2016-01-01

    During 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. The surface morphology of LHW-treated lignin observed with the scanning electron microscopy (SEM) was more porous and irregular than that of untreated lignin. Compared to the untreated lignin, the surface area, total pore volume, and average pore size of LHW-treated lignin tested with the Brunner-Emmet-Teller (BET) measurement were increased. FTIR analysis showed that the chemical structure of lignin was broken down in the LHW process. Additionally, the impact of untreated and treated lignin on the enzymatic hydrolysis of cellulose was also explored. The LHW-treated lignin had little impact on the cellulase adsorption and enzyme activities and somehow could improve the enzymatic hydrolysis of cellulose.

  11. Effects of lignin-metal complexation on enzymatic hydrolysis of cellulose.

    PubMed

    Liu, H; Zhu, J Y; Fu, S Y

    2010-06-23

    This study investigated the inhibition of enzymatic hydrolysis by unbound lignin (soluble and insoluble) with or without the addition of metal compounds. Sulfonated, Organosolv, and Kraft lignin were added in aqueous enzyme-cellulose systems at different concentrations before hydrolysis. The measured substrate enzymatic digestibility (SED) of cellulose was decreased by 15% when SL was added to a concentration of 0.1 g/L due to nonproductive adsorption of enzymes onto lignin. Cu(II) and Fe(III) were found to inhibit enzymatic cellulose hydrolysis in the presence of lignin. Ca(II) and Mg(II) were found to reduce or eliminate nonproductive enzyme adsorption by the formation of lignin-metal complex. The addition of Ca(II) or Mg(II) to a concentration of 10 mM can almost completely eliminate the reduction in SED caused by the nonproductive enzyme adsorption onto the lignins studied (SL, OL, or KL at concentration of 0.1 g/L). Ca(II) was also found to reduce the inhibitive effect of bound lignin in pretreated wood substrate, suggesting that Ca(II) can also form complex with bound lignin on pretreated solid lignocelluloses. Significant improvement in SED of about over 27% of a eucalyptus substrate produced by sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) was achieved with the application of Ca(II).

  12. Structural Changes of Lignin after Liquid Hot Water Pretreatment and Its Effect on the Enzymatic Hydrolysis

    PubMed Central

    Zhuang, Xinshu; Qi, Wei; Yu, Qiang; Wang, Qiong

    2016-01-01

    During 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. The surface morphology of LHW-treated lignin observed with the scanning electron microscopy (SEM) was more porous and irregular than that of untreated lignin. Compared to the untreated lignin, the surface area, total pore volume, and average pore size of LHW-treated lignin tested with the Brunner-Emmet-Teller (BET) measurement were increased. FTIR analysis showed that the chemical structure of lignin was broken down in the LHW process. Additionally, the impact of untreated and treated lignin on the enzymatic hydrolysis of cellulose was also explored. The LHW-treated lignin had little impact on the cellulase adsorption and enzyme activities and somehow could improve the enzymatic hydrolysis of cellulose. PMID:27563678

  13. Biological Pretreatment of Rubberwood with Ceriporiopsis subvermispora for Enzymatic Hydrolysis and Bioethanol Production

    PubMed Central

    Nazarpour, Forough; Abdullah, Dzulkefly Kuang; Abdullah, Norhafizah; Motedayen, Nazila; Zamiri, Reza

    2013-01-01

    Rubberwood (Hevea brasiliensis), a potential raw material for bioethanol production due to its high cellulose content, was used as a novel feedstock for enzymatic hydrolysis and bioethanol production using biological pretreatment. To improve ethanol production, rubberwood was pretreated with white rot fungus Ceriporiopsis subvermispora to increase fermentation efficiency. The effects of particle size of rubberwood (1 mm, 0.5 mm, and 0.25 mm) and pretreatment time on the biological pretreatment were first determined by chemical analysis and X-ray diffraction and their best condition obtained with 1 mm particle size and 90 days pretreatment. Further morphological study on rubberwood with 1 mm particle size pretreated by fungus was performed by FT-IR spectra analysis and SEM observation and the result indicated the ability of this fungus for pretreatment. A study on enzymatic hydrolysis resulted in an increased sugar yield of 27.67% as compared with untreated rubberwood (2.88%). The maximum ethanol concentration and yield were 17.9 g/L and 53% yield, respectively, after 120 hours. The results obtained demonstrate that rubberwood pretreated by C. subvermispora can be used as an alternative material for the enzymatic hydrolysis and bioethanol production. PMID:24167813

  14. Enzymatic hydrolysis of autohydrolyzed wheat straw followed by refining to produce fermentable sugars.

    PubMed

    Ertas, Murat; Han, Qiang; Jameel, Hasan; Chang, Hou-min

    2014-01-01

    Wheat straw was pretreated using an autohydrolysis process with different temperatures (160-200 °C) and times (10-20 min) in order to allow the recovery of hemicellulose in the filtrate and help open up the structure of the biomass for improved accessibility of enzymes during enzymatic hydrolysis. Autohydrolysis at 190 °C for 10 min provided the highest overall sugar (12.2/100g raw wheat straw) in the autohydrolysis filtrate and recovered 62.3% of solid residue. Before enzymatic hydrolysis, the pulps obtained from each pretreatment condition were subjected to a refining post-treatment to improve enzyme accessibility. Enzymatic hydrolysis was performed for all the pretreated solids with and without refining post-treatment at the enzyme loadings of 4 and 10 FPU/g oven dry substrate for 96 h. A total of 30.4 g sugars can be recovered from 100g wheat straw at 180 °C for 20 min with 4 FPU/g enzyme charge.

  15. Effect and aftereffect of gamma radiation pretreatment on enzymatic hydrolysis of wheat straw.

    PubMed

    Yang, Chunping; Shen, Zhiqiang; Yu, Guoce; Wang, Jianlong

    2008-09-01

    Irradiation pretreatment of wheat straw was carried out at different doses by using Co-60 gamma radiation. The weight loss and fragility of wheat straw after irradiation, the combination effect of irradiation and mechanical crushing on enzymatic hydrolysis of wheat straw as well as the aftereffect of irradiation were examined. It is shown that irradiation can cause significant breakdown of the structure of wheat straw. The weight loss of wheat straw increased and the size distribution after crushing moved to fine particles at elevated irradiation doses. The glucose yield of enzymatic hydrolysis of wheat straw increased with increasing doses and achieved the maximum (13.40%) at 500 kGy. A synergistic effect between irradiation and crushing was observed, with a glucose yield of 10.24% at a dose of 500 kGy with powder of 140 mesh. The aftereffect of irradiation had important impact on enzymatic hydrolysis of wheat straw. The aftereffect (at 22nd day) of 400 kGy irradiation accounted for 20.0% of the initial effect for glucose production, and the aftereffects of 50, 100, 200 (at 9th day) and 300 kGy (at 20th day) accounted for 12.9%, 14.9%, 8.9% and 9.1%, respectively, for reducing sugar production.

  16. New miniature stirred-tank bioreactors for parallel study of enzymatic biomass hydrolysis.

    PubMed

    Riedlberger, Peter; Weuster-Botz, Dirk

    2012-02-01

    Many factors strongly influence the enzymatic hydrolysis of biomass to fermentable sugars (feedstock composition, pretreatment, enzymes and enzyme loading). In order to optimize the reaction conditions for the hydrolysis of biomass, an accurate high-throughput bioprocess development tool is mandatory, which enables a parallelization and an easy scale-up. New S-shaped impellers were developed for magnetically inductive driven stirred-tank bioreactors at a 10mL-scale. An efficient and reproducible homogenization was shown at 20% w/w solids loading of microcrystalline cellulose and at, 4-10% with wheat straw in 48 parallel operated stirred-tank bioreactors. The scale-up was successfully validated for the enzymatic hydrolysis of wheat straw suspensions and microcrystalline cellulose mixtures by application of a cellulase complex at a milliliter- and liter-scale. As an example, the parallel stirred-tank bioreactor system was applied for the evaluation of enzymatic batch hydrolyses of plant materials with varying pretreatments. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Production of wheat gluten hydrolysates with reduced antigenicity employing enzymatic hydrolysis combined with downstream unit operations.

    PubMed

    Merz, Michael; Kettner, Lucas; Langolf, Emma; Appel, Daniel; Blank, Imre; Stressler, Timo; Fischer, Lutz

    2016-08-01

    Due to allergies or other health disorders a certain segment of the population is not able to safely consume some plant proteins, which are the main protein support in human nutrition. Coeliac disease is a prominent autoimmune disorder and requires a strict adherence to a gluten-free diet. The aim of this study was to identify suitable combinations of enzymatic hydrolysis and common unit operations in food processing (centrifugation, ultra-filtration) to produce gluten-free wheat gluten hydrolysates for food application. To analyse the hydrolysates, a simple and cheap competitive ELISA protocol was designed and validated in this study as well. The competitive ELISA was validated using gliadin spiked skim milk protein hydrolysates, due to the latter application of the assay. The limit of quantification was 4.19 mg kg(-1) , which allowed the identification of gluten-free (<20 mg kg(-1) ) hydrolysates. Enzymatic hydrolysis, including the type of peptidase, and the downstream processing greatly affected the antigenicity of the hydrolysates. Enzymatic hydrolysis and downstream processing operations, such as centrifugation and ultra-filtration, reduced the antigenicity of wheat gluten hydrolysates. Gluten-free hydrolysates were obtained with Flavourzyme after centrifugation (25 g L(-1) substrate) and after 1 kDa ultra-filtration (100 g L(-1) substrate). A multiple peptidase complex, such as Flavourzyme, seems to be required for the production of gluten-free hydrolysates. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  18. Hydrolysis and large scale ultrafiltration study of alfalfa protein concentrate enzymatic hydrolysate.

    PubMed

    D'Alvise; Lesueur-Lambert; Fertin; Dhulster; Guillochon

    2000-08-01

    Batch enzymatic hydrolysis of insoluble Alfalfa Protein Concentrate by Delvolase was carried out at laboratory and at pilot-plant scale coupled to an ultrafiltration reactor with a mineral tubular membrane. Parametric studies were carried out on the batch system to determine the biochemical and hydrodynamical optimum conditions. The hydrolysis conditions selected were 40 degrees C, pH 9.5, initial substrate level 3 g protein/100 g and the enzyme substrate ratio 152 U/g protein. After 5 h of hydrolysis, 96% of the total amount of initial nitrogen was solubilized. The ultrafiltration conditions selected were a 10 000 Nominal Molecular Weight Cut-Off, a transmembrane pressure of 1.5 bar, a flux velocity of 0.8 m/s. Fifty percent of the initial nitrogen appeared in the permeate.

  19. Optimal control strategy for fed-batch enzymatic hydrolysis of lignocellulosic biomass based on epidemic modeling.

    PubMed

    Tai, Chao; Keshwani, Deepak R; Voltan, Diego S; Kuhar, Pankaj S; Engel, Aaron J

    2015-07-01

    A mathematical optimal control strategy for feeding operation was developed for fed-batch enzymatic hydrolysis of dilute acid pretreated lignocellulosic biomass based on a modified epidemic model. Cellulose conversion was maximized and glucose concentration achieved highest possible value over a fixed hydrolysis time. Boundaries of feeding rate and lignin content were set for feasible controls. Using the optimal control feeding strategy, glucose concentration and accumulated cellulose conversion reached up to 77.31 g/L and 72.08% in 100 h, which are 108.76% and 37.50% higher than in batch hydrolysis with same amount of enzyme consumption. Solids content in feeding source has a significant interference on system mass transfer. Optimal control is a useful tool for guiding operations in fed-batch and continuous processes as it enables process optimization through clear objective functions and feasible controls. © 2015 Wiley Periodicals, Inc.

  20. Benefits from additives and xylanase during enzymatic hydrolysis of bamboo shoot and mature bamboo.

    PubMed

    Li, Kena; Wang, Xiao; Wang, Jingfeng; Zhang, Junhua

    2015-09-01

    Effects of additives (BSA, PEG 6000, and Tween 80) on enzymatic hydrolysis of bamboo shoot and mature bamboo fractions (bamboo green, bamboo timber, bamboo yellow, bamboo node, and bamboo branches) by cellulases and/or xylanase were evaluated. The addition of additives was comparable to the increase of cellulase loadings in the conversion of cellulose and xylan in bamboo fractions. Supplementation of xylanase (1 mg/g DM) with cellulases (10 FPU/g DM) in the hydrolysis of bamboo fractions was more efficient than addition of additives in the production of glucose and xylose. Moreover, addition of additives could further increase the glucose release from different bamboo fractions by cellulases and xylanase. Bamboo green exhibited the lowest hydrolyzability. Almost all of the polysaccharides in pretreated bamboo shoot fractions were hydrolyzed by cellulases with the addition of additives or xylanase. Additives and xylanase showed great potential for reducing cellulase requirement in the hydrolysis of bamboo.

  1. Kinetic analysis of enzymatic hydrolysis of crystalline cellulose by cellobiohydrolase using an amperometric biosensor.

    PubMed

    Tatsumi, Hirosuke; Katano, Hajime; Ikeda, Tokuji

    2006-10-15

    An amperometric biosensor for the detection of cellobiose has been introduced to study the kinetics of enzymatic hydrolysis of crystalline cellulose by cellobiohydrolase. By use of a sensor in which pyrroloquinoline quinone-dependent glucose dehydrogenase was immobilized on the surface of electrode, direct and continuous observation of the hydrolysis can be achieved even in a thick cellulose suspension. The steady-state rate of the hydrolysis increased with increasing concentrations of the enzyme to approach a saturation value and was proportional to the amount of the substrate. The experimental results can be explained well by the rate equations derived from a three-step mechanism consisting of the adsorption of the free enzyme onto the surface of the substrate, the reaction of the adsorbed enzyme with the substrate, and the liberation of the product. The catalytic constant of the adsorbed enzyme was determined to be 0.044+/-0.011s(-1).

  2. Ethanol production by enzymatic hydrolysis: parametric analysis of a base-case process

    SciTech Connect

    Isaacs, S.H.

    1984-05-01

    A base-case flowsheet for an enzymatic hydrolysis process is presented. Included is a parametric sensitivity analysis to identify key research issues and an assessment of this technology. The plant discussed is a large-scale facility, producing 50 million gallons of ethanol per year. The plant design is based on the process originally conceived by the US National Army Command and consists of these process steps: pretreatment; enzyme production; enzyme hydrolysis; fermentation; and distillation. The base-case design parameters are based on recent laboratory data from Lawrence Berkeley Laboratories and the University of California at Berkeley. The selling price of ethanol is used to compare variations in the base-case operating parameters, which include hydrolysis efficiencies, capital costs, enzyme production efficiencies, and enzyme recycle. 28 references, 38 figures, 8 tables.

  3. Enzymatic Hydrolysis Does Not Reduce the Biological Reactivity of Soybean Proteins for All Allergic Subjects.

    PubMed

    Panda, Rakhi; Tetteh, Afua O; Pramod, Siddanakoppalu N; Goodman, Richard E

    2015-11-04

    Many soybean protein products are processed by enzymatic hydrolysis to attain desirable functional food properties or in some cases to reduce allergenicity. However, few studies have investigated the effects of enzymatic hydrolysis on the allergenicity of soybean products. In this study the allergenicity of soybean protein isolates (SPI) hydrolyzed by Alcalase, trypsin, chymotrypsin, bromelain, or papain was evaluated by IgE immunoblots using eight soybean-allergic patient sera. The biological relevance of IgE binding was evaluated by a functional assay using a humanized rat basophilic leukemia (hRBL) cell line and serum from one subject. Results indicated that hydrolysis of SPI by the enzymes did not reduce the allergenicity, and hydrolysis by chymotrypsin or bromelain has the potential to increase the allergenicity of SPI. Two-dimensional (2D) immunoblot and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of the chymotrypsin-hydrolyzed samples indicated fragments of β-conglycinin protein are responsible for the apparent higher allergenic potential of digested SPI.

  4. Inhibition effects of dilute-acid prehydrolysate of corn stover on enzymatic hydrolysis of Solka Floc.

    PubMed

    Kothari, Urvi D; Lee, Yoon Y

    2011-11-01

    Dilute-acid pretreatment liquor (PL) produced at NREL through a continuous screw-driven reactor was analyzed for sugars and other potential inhibitory components. Their inhibitory effects on enzymatic hydrolysis of Solka Floc were investigated. When the PL was mixed into the enzymatic hydrolysis reactor at 1:1 volume ratio, the glucan and xylan digestibility decreased by 63% and 90%, respectively. The tolerance level of the enzyme for each inhibitor was determined. Of the identified degradation components, acetic acid was found to be the strongest inhibitor for cellulase activity, as it decreased the glucan yield by 10% at 1 g/L. Among the sugars, cellobiose and glucose were found to be strong inhibitors to glucan hydrolysis, whereas xylose is a strong inhibitor to xylan hydrolysis. Xylo-oligomers inhibit xylan digestibility more strongly than the glucan digestibility. Inhibition by the PL was higher than that of the simulated mixture of the identifiable components. This indicates that some of the unidentified degradation components, originated mostly from lignin, are potent inhibitors to the cellulase enzyme. When the PL was added to a simultaneous saccharification and co-fermentation using Escherichia coli KO11, the bioprocess was severely inhibited showing no ethanol formation or cell growth.

  5. BSA treatment to enhance enzymatic hydrolysis of cellulose in lignin containing substrates.

    PubMed

    Yang, Bin; Wyman, Charles E

    2006-07-05

    Cellulase and bovine serum albumin (BSA) were added to Avicel cellulose and solids containing 56% cellulose and 28% lignin from dilute sulfuric acid pretreatment of corn stover. Little BSA was adsorbed on Avicel cellulose, while pretreated corn stover solids adsorbed considerable amounts of this protein. On the other hand, cellulase was highly adsorbed on both substrates. Adding a 1% concentration of BSA to dilute acid pretreated corn stover prior to enzyme addition at 15 FPU/g cellulose enhanced filter paper activity in solution by about a factor of 2 and beta-glucosidase activity in solution by about a factor of 14. Overall, these results suggested that BSA treatment reduced adsorption of cellulase and particularly beta-glucosidase on lignin. Of particular note, BSA treatment of pretreated corn stover solids prior to enzymatic hydrolysis increased 72 h glucose yields from about 82% to about 92% at a cellulase loading of 15 FPU/g cellulose or achieved about the same yield at a loading of 7.5 FPU/g cellulose. Similar improvements were also observed for enzymatic hydrolysis of ammonia fiber explosion (AFEX) pretreated corn stover and Douglas fir treated by SO(2) steam explosion and for simultaneous saccharification and fermentation (SSF) of BSA pretreated corn stover. In addition, BSA treatment prior to hydrolysis reduced the need for beta-glucosidase supplementation of SSF. The results are consistent with non-specific competitive, irreversible adsorption of BSA on lignin and identify promising strategies to reduce enzyme requirements for cellulose hydrolysis.

  6. Enhancement of high-solids enzymatic hydrolysis of corncob residues by bisulfite pretreatment for biorefinery.

    PubMed

    Xing, Yang; Bu, Lingxi; Zheng, Tianran; Liu, Shijie; Jiang, Jianxin

    2016-12-01

    Co-production of glucose, furfural and other green materials based on a lignocellulosic biorefinery is a promising way to realize the commercial application of corncob residues. An effective process was developed for glucose production using low temperature bisulfite pretreatment and high-solids enzymatic hydrolysis. Corncob residues from furfural production (FRs) were pretreated with 0.1g NaHSO3/g dry substrate at 100°C for 3h. Lignin was sulfonated and sulfonic groups were produced during pretreatment, which resulted in decreasing the zeta potential of the samples. Compared with raw material, bisulfite pretreatment of FRs increased the glucose yield from 18.6 to 99.45% after 72h hydrolysis at a solids loading of 12.5%. The hydrolysis residues showed a relatively high thermal stability and concentrated high derivatives. Direct pretreatment followed by enzymatic hydrolysis is an environmentally-friendly and economically-feasible method for the production of glucose and high-purity lignin, which could be further converted into high-value products. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Small angle neutron scattering reveals pH-dependent conformational changes in Trichoderma reesei cellobiohydrolase I: implications for enzymatic activity.

    PubMed

    Pingali, Sai Venkatesh; O'Neill, Hugh M; McGaughey, Joseph; Urban, Volker S; Rempe, Caroline S; Petridis, Loukas; Smith, Jeremy C; Evans, Barbara R; Heller, William T

    2011-09-16

    Cellobiohydrolase I (Cel7A) of the fungus Trichoderma reesei (now classified as an anamorph of Hypocrea jecorina) hydrolyzes crystalline cellulose to soluble sugars, making it of key interest for producing fermentable sugars from biomass for biofuel production. The activity of the enzyme is pH-dependent, with its highest activity occurring at pH 4-5. To probe the response of the solution structure of Cel7A to changes in pH, we measured small angle neutron scattering of it in a series of solutions having pH values of 7.0, 6.0, 5.3, and 4.2. As the pH decreases from 7.0 to 5.3, the enzyme structure remains well defined, possessing a spatial differentiation between the cellulose binding domain and the catalytic core that only changes subtly. At pH 4.2, the solution conformation of the enzyme changes to a structure that is intermediate between a properly folded enzyme and a denatured, unfolded state, yet the secondary structure of the enzyme is essentially unaltered. The results indicate that at the pH of optimal activity, the catalytic core of the enzyme adopts a structure in which the compact packing typical of a fully folded polypeptide chain is disrupted and suggest that the increased range of structures afforded by this disordered state plays an important role in the increased activity of Cel7A through conformational selection.

  8. The dual effects of lignin content on enzymatic hydrolysis using film composed of cellulose and lignin as a structure model.

    PubMed

    Zhang, Lu; Zhang, Liming; Zhou, Tian; Wu, Yuying; Xu, Feng

    2016-01-01

    The degree of delignification during pretreatment is a critical question for economic conversion of biomass to sugar platform. Many models have been used to study the optimum lignin content in biomass, but few of them are able to study without disturbances, such as the complex component and structure of biomass. A novel film model composed of only cellulose and lignin was used to investigate the effect of lignin on enzymatic hydrolysis. High lignin-cellulose proportion (10.00-31.25%) hindered enzymatic hydrolysis, whereas low lignin-cellulose proportion (2.00-8.00%) showed a notable potential to promote enzymatic hydrolysis. The enzymatic hydrolysis rate of lignin-cellulose (6.00%) film was 11.5% higher than that of pure cellulose films. Further study indicated that the promotion was due to the enhancement of film porosity and roughness by residual lignin. Thus, based on the biomimetic model, excessive delignification is not recommended in view of efficient conversion and economy.

  9. Effects of a steam explosion pretreatment on sugar production by enzymatic hydrolysis and structural properties of reed straw.

    PubMed

    Hu, Qiulong; Su, Xiaojun; Tan, Lin; Liu, Xianghua; Wu, Anjun; Su, Dingding; Tian, Kaizhong; Xiong, Xingyao

    2013-01-01

    Reed lignocellulose was subjected to a steam explosion pretreatment to obtain a high conversion rate of sugar after subsequent enzymatic hydrolysis using a commercial cellulase mixture. Under conditions of differing temperature (200 °C, 220 °C and 240 °C) and residence time (2, 5, and 8 min), the effect of the pretreatment on the sugar yield from enzymatic hydrolysis was studied. The highest respective reducing sugar and glucose yields were 36.14% and 15.35% after 60-h enzymatic hydrolysis of reed straw that had been pretreated with a steam explosion at 220 °C for 5 min. Fourier transform infrared spectrophotometry (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used in this study to comprehensively investigate the steam explosion-induced changes in the organizational structure and morphological properties of reed straw to analyze the reason for the increased sugar yield from enzymatic hydrolysis after the steam explosion.

  10. Effect of alkali lignins with different molecular weights from alkali pretreated rice straw hydrolyzate on enzymatic hydrolysis.

    PubMed

    Li, Yun; Qi, Benkun; Luo, Jianquan; Wan, Yinhua

    2016-01-01

    This study investigated the effect of alkali lignins with different molecular weights on enzymatic hydrolysis of lignocellulose. Different alkali lignins fractions, which were obtained from cascade ultrafiltration, were added into the dilute acid pretreated (DAP) and alkali pretreated (AP) rice straws respectively during enzymatic hydrolysis. The results showed that the addition of alkali lignins enhanced the hydrolysis and the enhancement for hydrolysis increased with increasing molecular weights of alkali lignins, with maximum enhancement being 28.69% for DAP and 20.05% for AP, respectively. The enhancement was partly attributed to the improved cellulase activity, and filter paper activity increased by 18.03% when adding lignin with highest molecular weight. It was found that the enhancement of enzymatic hydrolysis was correlated with the adsorption affinity of cellulase on alkali lignins, and the difference in surface charge and hydrophobicity of alkali lignins were responsible for the difference in affinity between cellulase and lignins.

  11. Facile, room-temperature pre-treatment of rice husks with tetrabutylphosphonium hydroxide: Enhanced enzymatic and acid hydrolysis yields.

    PubMed

    Lau, B B Y; Luis, E T; Hossain, M M; Hart, W E S; Cencia-Lay, B; Black, J J; To, T Q; Aldous, L

    2015-12-01

    Aqueous solutions of tetrabutylphosphonium hydroxide have been evaluated as pretreatment media for rice husks, prior to sulphuric acid hydrolysis or cellulase enzymatic hydrolysis. Varying the water:tetrabutylphosphonium hydroxide ratio varied the rate of delignification, as well as silica, lignin and cellulose solubility. Pre-treatment with 60wt% hydroxide dissolved the rice husk and the regenerated material was thus heavily disrupted. Sulphuric acid hydrolysis of 60wt%-treated samples yielded the highest amount of glucose per gram of rice husk. Solutions with good lignin and silica solubility but only moderate to negligible cellulose solubility (10-40wt% hydroxide) were equally effective as pre-treatment media for both acid and enzymatic hydrolysis. However, pre-treatment with 60wt% hydroxide solutions was incompatible with downstream enzymatic hydrolysis. This was due to significant incorporation of phosphonium species in the regenerated biomass, which significantly inhibited the activity of the cellulase enzymes.

  12. A Factorial Analysis Study on Enzymatic Hydrolysis of Fiber Pressed Oil Palm Frond for Bioethanol Production

    NASA Astrophysics Data System (ADS)

    Hashim, F. S.; Yussof, H. W.; Zahari, M. A. K. M.; Illias, R. M.; Rahman, R. A.

    2016-03-01

    Different technologies have been developed to for the conversion of lignocellulosic biomass to suitable fermentation substrates for bioethanol production. The enzymatic conversion of cellulose seems to be the most promising technology as it is highly specific and does not produce substantial amounts of unwanted byproducts. The effects of agitation speed, enzyme loading, temperature, pH and reaction time on the conversion of glucose from fiber pressed oil palm frond (FPOPF) for bioethanol production were screened by statistical analysis using response surface methodology (RSM). A half fraction two-level factorial analysis with five factors was selected for the experimental design to determine the best enzymatic conditions that produce maximum amount of glucose. FPOPF was pre-treated with alkaline prior to enzymatic hydrolysis. The enzymatic hydrolysis was performed using a commercial enzyme Cellic CTec2. From this study, the highest yield of glucose concentration was 9.736 g/L at 72 hours reaction time at 35 °C, pH 5.6, and 1.5% (w/v) of enzyme loading. The model obtained was significant with p-value <0.0001. It is suggested that this model had a maximum point which is likely to be the optimum point and possible for the optimization process.

  13. Production and characterization of cowpea protein hydrolysate with optimum nitrogen solubility by enzymatic hydrolysis using pepsin.

    PubMed

    Mune Mune, Martin Alain; Minka, Samuel René

    2017-06-01

    Cowpea is a source of low-cost and good nutritional quality protein for utilization in food formulations in replacement of animal proteins. Therefore it is necessary that cowpea protein exhibits good functionality, particularly protein solubility which affects the other functional properties. The objective of this study was to produce cowpea protein hydrolysate exhibiting optimum solubility by the adequate combination of hydrolysis parameters, namely time, solid/liquid ratio (SLR) and enzyme/substrate ratio (ESR), and to determine its functional properties and molecular characteristics. A Box-Behnken experimental design was used for the experiments, and a second-order polynomial to model the effects of hydrolysis time, SLR and ESR on the degree of hydrolysis and nitrogen solubility index. The optimum hydrolysis conditions of time 208.61 min, SLR 1/15 (w/w) and ESR 2.25% (w/w) yielded a nitrogen solubility of 75.71%. Protein breakdown and the peptide profile following enzymatic hydrolysis were evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and size exclusion chromatography. Cowpea protein hydrolysate showed higher oil absorption capacity, emulsifying activity and foaming ability compared with the concentrate. The solubility of cowpea protein hydrolysate was adequately optimized by response surface methodology, and the hydrolysate showed adequate functionality for use in food. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. Antioxidative activities of hydrolysates from edible birds nest using enzymatic hydrolysis

    NASA Astrophysics Data System (ADS)

    Muhammad, Nurul Nadia; Babji, Abdul Salam; Ayub, Mohd Khan

    2015-09-01

    Edible bird's nest protein hydrolysates (EBN) were prepared via enzymatic hydrolysis to investigate its antioxidant activity. Two types of enzyme (alcalase and papain) were used in this study and EBN had been hydrolysed with different hydrolysis time (30, 60, 90 and 120 min). Antioxidant activities in EBN protein hydrolysate were measured using DPPH, ABTS+ and Reducing Power Assay. From this study, increased hydrolysis time from 30 min to 120 min contributed to higher DH, as shown by alcalase (40.59%) and papain (24.94%). For antioxidant assay, EBN hydrolysed with papain showed higher scavenging activity and reducing power ability compared to alcalase. The highest antioxidant activity for papain was at 120 min hydrolysis time with ABTS (54.245%), DPPH (49.78%) and Reducing Power (0.0680). Meanwhile for alcalase, the highest antioxidant activity was at 30 min hydrolysis time. Even though scavenging activity for EBN protein hydrolysates were high, the reducing power ability was quite low as compared to BHT and ascorbic Acid. This study showed that EBN protein hydrolysate with alcalase and papain treatments potentially exhibit high antioxidant activity which have not been reported before.

  15. Novel synthesis of leucoside by enzymatic hydrolysis of tea seed extract.

    PubMed

    Chung, Dae-won; Lee, Seul Bi

    2013-01-01

    The application of tea seed extract (TSE) has been widely investigated owing to its biological activities. In this paper, two flavonol triglycosides found in TSE, camelliaside A (CamA) and camelliaside B (CamB), were subjected to hydrolysis in the presence of three commercial enzyme complexes of the Pectinex® series, 5XL, XXL and Ultra SP-L (Ultra). XXL and 5XL induced stepwise deglycosylation of CamA and CamB to yield kaempferol diglycoside (nicotiflorin), kaempferol monoglycoside (astragalin) and kaempferol, while Ultra produced an additional new compound (1) that had not been observed in earlier studies. Upon hydrolysis of isolated CamA and CamB, compound (1) was obtained only from CamB. Both the molecular ion peak in liquid chromatography/mass spectrometry and the ¹H and ¹³C nuclear magnetic resonance spectra of (1) isolated by Ultra-induced hydrolysis of TSE indicated that (1) was kaempferol 3-O-β-xylopyranosyl (1 → 2)-β-glucopyranoside (leucoside), formed by selective hydrolysis of the rhamnosyl moiety of CamB. Pure leucoside can be prepared by enzymatic partial hydrolysis of TSE. This is the first study to address the synthesis of pure leucoside from a natural source. Copyright © 2012 Society of Chemical Industry.

  16. Process evaluation of enzymatic hydrolysis with filtrate recycle for the production of high concentration sugars.

    PubMed

    Xue, Ying; Rusli, Jannov; Chang, Hou-Min; Phillips, Richard; Jameel, Hasan

    2012-02-01

    Process simulation and lab trials were carried out to demonstrate and confirm the efficiency of the concept that recycling hydrolysate at low total solid enzymatic hydrolysis is one of the options to increase the sugar concentration without mixing problems. Higher sugar concentration can reduce the capital cost for fermentation and distillation because of smaller retention volume. Meanwhile, operation cost will also decrease for less operating volume and less energy required for distillation. With the computer simulation, time and efforts can be saved to achieve the steady state of recycling process, which is the scenario for industrial production. This paper, to the best of our knowledge, is the first paper discussing steady-state saccharification with recycling of the filtrate form enzymatic hydrolysis to increase sugar concentration. Recycled enzymes in the filtrate (15-30% of the original enzyme loading) resulted in 5-10% higher carbohydrate conversion compared to the case in which recycled enzymes were denatured. The recycled hydrolysate yielded 10% higher carbohydrate conversion compared to pure sugar simulated hydrolysate at the same enzyme loading, which indicated hydrolysis by-products could boost enzymatic hydrolysis. The high sugar concentration (pure sugar simulated) showed inhibition effect, since about 15% decrease in carbohydrate conversion was observed compared with the case with no sugar added. The overall effect of hydrolysate recycling at WinGEMS simulated steady-state conditions with 5% total solids was increasing the sugar concentration from 35 to 141 g/l, while the carbohydrate conversion was 2% higher for recycling at steady state (87%) compared with no recycling strategy (85%). Ten percent and 15% total solid processes were also evaluated in this study.

  17. Determination of glucose and ethanol after enzymatic hydrolysis and fermentation of biomass using Raman spectroscopy.

    PubMed

    Shih, Chien-Ju; Smith, Emily A

    2009-10-27

    Raman spectroscopy has been used for the quantitative determination of the conversion efficiency at each step in the production of ethanol from biomass. The method requires little sample preparation; therefore, it is suitable for screening large numbers of biomass samples and reaction conditions in a complex sample matrix. Dilute acid or ammonia-pretreated corn stover was used as a model biomass for these studies. Ammonia pretreatment was suitable for subsequent measurements with Raman spectroscopy, but dilute acid-pretreated corn stover generated a large background signal that surpassed the Raman signal. The background signal is attributed to lignin, which remains in the plant tissue after dilute acid pretreatment. A commercial enzyme mixture was used for the enzymatic hydrolysis of corn stover, and glucose levels were measured with a dispersive 785 nm Raman spectrometer. The glucose detection limit in hydrolysis liquor by Raman spectroscopy was 8 g L(-1). The mean hydrolysis efficiency for three replicate measurements obtained with Raman spectroscopy (86+/-4%) was compared to the result obtained using an enzymatic reaction with UV-vis spectrophotometry detection (78+/-8%). The results indicate good accuracy, as determined using a Student's t-test, and better precision for the Raman spectroscopy measurement relative to the enzymatic detection assay. The detection of glucose in hydrolysis broth by Raman spectroscopy showed no spectral interference, provided the sample was filtered to remove insoluble cellulose prior to analysis. The hydrolysate was further subjected to fermentation to yield ethanol. The detection limit for ethanol in fermentation broth by Raman spectroscopy was found to be 6 g L(-1). Comparison of the fermentation efficiencies measured by Raman spectroscopy (80+/-10%) and gas chromatography-mass spectrometry (87+/-9%) were statistically the same. The work demonstrates the utility of Raman spectroscopy for screening the entire conversion process to

  18. Continuous hydrolysis of modified wheat gluten in an enzymatic membrane reactor.

    PubMed

    Cui, Jie; Kong, Xiangzhen; Hua, Yufei; Zhou, Huiming; Liu, Qing

    2011-12-01

    The low solubility of wheat gluten is one of the major limitations to its use in food processing, and enzymatic hydrolysis has been found to be an effective way to prepare more soluble bioactive peptides from gluten. The aim of this study was to prepare bioactive peptides from modified wheat gluten (MWG) in a continuous enzymatic membrane reactor (EMR) that allowed rapid separation of low-molecular-weight peptides from hydrolysates, thus avoiding the disadvantages of batch reaction such as inefficient use of enzymes, inconsistent products due to batch-to-batch variation, substrate-product inhibition, low productivity and excessive hydrolysis. Wheat gluten was modified to decrease its lipid and starch contents in order to prevent membrane fouling. The optimal working conditions for Alcalase to hydrolyse MWG in the EMR were a substrate concentration of 20 g L(-1) , an enzyme/substrate ratio of 0.03, an operating pressure of 0.04 MPa, a temperature of 40 °C and a pH of 9. The operating stability of the EMR (including residual enzyme activity, productivity and capacity) was high. The permeate fractions showed antioxidant activities that were mostly due to low-molecular-weight peptides. A simple theoretical kinetic model was successfully applied to the enzymatic hydrolysis of MWG in the EMR. Modification of wheat gluten made the continuous enzymatic membrane reaction more efficient and the EMR proved to be an effective means of producing peptides with particular properties and bioactivities. The permeate fractions (mainly < 1000 Da) were homogeneous and stable and also showed strong antioxidant activities. Copyright © 2011 Society of Chemical Industry.

  19. Effects of agitation on particle-size distribution and enzymatic hydrolysis of pretreated spruce and giant reed

    PubMed Central

    2014-01-01

    Background Mixing is an energy demanding process which has been previously shown to affect enzymatic hydrolysis. Concentrated biomass slurries are associated with high and non-Newtonian viscosities and mixing in these systems is a complex task. Poor mixing can lead to mass and/or heat transfer problems as well as inhomogeneous enzyme distribution, both of which can cause possible yield reduction. Furthermore the stirring energy dissipation may impact the particle size which in turn may affect the enzymatic hydrolysis. The objective of the current work was to specifically quantify the effects of mixing on particle-size distribution (PSD) and relate this to changes in the enzymatic hydrolysis. Two rather different materials were investigated, namely pretreated Norway spruce and giant reed. Results Changes in glucan hydrolysis and PSD were measured as a function of agitation during enzymatic hydrolysis at fiber loadings of 7 or 13% water-insoluble solids (WIS). Enzymatic conversion of pretreated spruce was strongly affected by agitation rates at the higher WIS content. However, at low WIS content the agitation had almost no effect on hydrolysis. There was some effect of agitation on the hydrolysis of giant reed at high WIS loading, but it was smaller than that for spruce, and there was no measurable effect at low WIS loading. In the case of spruce, intense agitation clearly affected the PSD and resulted in a reduced mean particle size, whereas for giant reed the decrease in particle size was mainly driven by enzymatic action. However, the rate of enzymatic hydrolysis was not increased after size reduction by agitation. Conclusions The impact of agitation on the enzymatic hydrolysis clearly depends not only on feedstock but also on the solids loading. Agitation was found to affect the PSD differently for the examined pretreated materials spruce and giant reed. The fact that the reduced mean particle diameter could not explain the enhanced hydrolysis rates found for

  20. Particle size distribution of rice flour affecting the starch enzymatic hydrolysis and hydration properties.

    PubMed

    de la Hera, Esther; Gomez, Manuel; Rosell, Cristina M

    2013-10-15

    Rice flour is becoming very attractive as raw material, but there is lack of information about the influence of particle size on its functional properties and starch digestibility. This study evaluates the degree of dependence of the rice flour functional properties, mainly derived from starch behavior, with the particle size distribution. Hydration properties of flours and gels and starch enzymatic hydrolysis of individual fractions were assessed. Particle size heterogeneity on rice flour significantly affected functional properties and starch features, at room temperature and also after gelatinization; and the extent of that effect was grain type dependent. Particle size heterogeneity on rice flour induces different pattern in starch enzymatic hydrolysis, with the long grain having slower hydrolysis as indicated the rate constant (k). No correlation between starch digestibility and hydration properties or the protein content was observed. It seems that in intact granules interactions with other grain components must be taken into account. Overall, particle size fractionation of rice flour might be advisable for selecting specific physico-chemical properties.

  1. Biohydrogen production from enzymatic hydrolysis of food waste in batch and continuous systems

    PubMed Central

    Han, Wei; Yan, Yingting; Shi, Yiwen; Gu, Jingjing; Tang, Junhong; Zhao, Hongting

    2016-01-01

    In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35 g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen production of 5850 mL was achieved with a yield of 245.7 mL hydrogen/g glucose (1.97 mol hydrogen/mol glucose) in the batch system. In the continuous system, the effect of hydraulic retention time (HRT) on biohydrogen production from food waste hydrolysate was investigated. The optimal HRT obtained from this study was 6 h with the highest hydrogen production rate of 8.02 mmol/(h·L). Ethanol and acetate were the major soluble microbial products with low propionate production at all HRTs. Enzymatic hydrolysis of food waste could effectively accelerate hydrolysis speed, improve substrate utilization rate and increase hydrogen yield. PMID:27910937

  2. Biohydrogen production from enzymatic hydrolysis of food waste in batch and continuous systems.

    PubMed

    Han, Wei; Yan, Yingting; Shi, Yiwen; Gu, Jingjing; Tang, Junhong; Zhao, Hongting

    2016-12-02

    In this study, the feasibility of biohydrogen production from enzymatic hydrolysis of food waste was investigated. Food waste (solid-to-liquid ratio of 10%, w/v) was first hydrolyzed by commercial glucoamylase to release glucose (24.35 g/L) in the food waste hydrolysate. Then, the obtained food waste hydrolysate was used as substrate for biohydrogen production in the batch and continuous (continuous stirred tank reactor, CSTR) systems. It was observed that the maximum cumulative hydrogen production of 5850 mL was achieved with a yield of 245.7 mL hydrogen/g glucose (1.97 mol hydrogen/mol glucose) in the batch system. In the continuous system, the effect of hydraulic retention time (HRT) on biohydrogen production from food waste hydrolysate was investigated. The optimal HRT obtained from this study was 6 h with the highest hydrogen production rate of 8.02 mmol/(h·L). Ethanol and acetate were the major soluble microbial products with low propionate production at all HRTs. Enzymatic hydrolysis of food waste could effectively accelerate hydrolysis speed, improve substrate utilization rate and increase hydrogen yield.

  3. Effects of enzymatic hydrolysis on the allergenicity of whey protein concentrates.

    PubMed

    Duan, Cuicui; Yang, Lijie; Li, Aili; Zhao, Rui; Huo, Guicheng

    2014-08-01

    Cow's milk whey consists of many protein components and some of them are antigens to human and known to modulate immune responses. Enzymatic hydrolysis is a useful method to modify proteins with allergenicity. The objective of this study was to identify whether the in vitro enzymatic hydrolysis could reduce the allergenicity of whey protein concentrates (WPC). In this study, WPC were hydrolyzed by trypsin and twenty-four BALB/c mice were divided into three groups and fed with WPC formula and WPC hydrolysates formula, while the control mice received milk-free diet. The results revealed that there was no significant difference between the body weights among all groups. WPC-fed mice produced an elevated spleen lymphocyte proliferation level than WPC hydrolysates-fed mice and also produced higher levels of WPC-specific IgE in intestinal tract and serum in comparison to WPC hydrolysates-fed mice and control group. Significant up-regulation of plasma histamine levels were also observed and showed the same trend with IgE. The secretions of IL-4 and IL-5 were significantly enhanced by WPC. WPC significantly suppressed the secretion of IFN-γ while hydrolysates of WPC significantly increased the secretion of IFN-γ compared to control group. These results suggest that hydrolysis may play a role to reduce the allergenicity of WPC.

  4. Wet disk milling pretreatment without sulfuric acid for enzymatic hydrolysis of rice straw.

    PubMed

    Hideno, Akihiro; Inoue, Hiroyuki; Tsukahara, Kenichiro; Fujimoto, Shinji; Minowa, Tomoaki; Inoue, Seiichi; Endo, Takashi; Sawayama, Shigeki

    2009-05-01

    Rice straw has recently attracted interest in Japan as a potential source of raw material for ethanol production. Wet disk milling, a continuous pretreatment to enhance the enzymatic digestibility of rice straw, was compared with conventional ball milling and hot-compressed water treatment. Pretreated rice straw was evaluated by enzymatic hydrolysis using Acremonium cellulase and characterized by X-ray diffraction and scanning electron microscopy. Glucose and xylose yields by wet disk milling, ball milling, and hot-compressed water treatment were 78.5% and 41.5%, 89.4% and 54.3%, and 70.3% and 88.6%, respectively. Wet disk milling and hot-compressed water treatment increased sugar yields without decreasing their crystallinity. The feature size of the wet disk milled rice straw was similar to that of hot-compressed water-treated rice straw. The energy consumption of wet disk milling was lower than that of other pretreatments. Thus, wet disk milling is an economical, practical pretreatment for the enzymatic hydrolysis of lignocellulosic biomass, especially herbaceous biomass such as rice straw.

  5. Bio-conversion of apple pomace into ethanol and acetic acid: Enzymatic hydrolysis and fermentation.

    PubMed

    Parmar, Indu; Rupasinghe, H P Vasantha

    2013-02-01

    Enzymatic hydrolysis of cellulose present in apple pomace was investigated using process variables such as enzyme activity of commercial cellulase, pectinase and β-glucosidase, temperature, pH, time, pre-treatments and end product separation. The interaction of enzyme activity, temperature, pH and time had a significant effect (P<0.05) on release of glucose. Optimal conditions of enzymatic saccharification were: enzyme activity of cellulase, 43units; pectinase, 183units; β-glucosidase, 41units/g dry matter (DM); temperature, 40°C; pH 4.0 and time, 24h. The sugars were fermented using Saccharomyces cerevisae yielding 19.0g ethanol/100g DM. Further bio-conversion using Acetobacter aceti resulted in the production of acetic acid at a concentration of 61.4g/100g DM. The present study demonstrates an improved process of enzymatic hydrolysis of apple pomace to yield sugars and concomitant bioconversion to produce ethanol and acetic acid.

  6. Economic impact of total solids loading on enzymatic hydrolysis of dilute acid pretreated corn stover.

    PubMed

    Humbird, David; Mohagheghi, Ali; Dowe, Nancy; Schell, Daniel J

    2010-01-01

    In process integration studies of the biomass-to-ethanol conversion process, it is necessary to understand how cellulose conversion yields vary as a function of solids and enzyme loading and other key operating variables. The impact of solids loading on enzymatic cellulose hydrolysis of dilute acid pretreated corn stover slurry was determined using an experimental response surface design methodology. From the experimental work, an empirical correlation was obtained that expresses monomeric glucose yield from enzymatic cellulose hydrolysis as a function of solids loading, enzyme loading, and temperature. This correlation was used in a technoeconomic model to study the impact of solids loading on ethanol production economics. The empirical correlation was used to provide a more realistic assessment of process cost by accounting for changes in cellulose conversion yields at different solids and enzyme loadings as well as enzyme cost. As long as enzymatic cellulose conversion drops off at higher total solids loading (due to end-product inhibition or other factors), there is an optimum value for the total solids loading that minimizes the ethanol production cost. The optimum total solids loading shifts to higher values as enzyme cost decreases. © 2010 American Institute of Chemical Engineers

  7. Subcritical CO2 pretreatment of sugarcane bagasse and its enzymatic hydrolysis for sugar production.

    PubMed

    Zhang, Hongdan; Wu, Shubin

    2013-12-01

    The present work investigated the effects of subcritical CO2 pretreatment of sugarcane bagasse at different CO2 pressure, pretreatment time, and temperature with relative high-solid concentration (15% w/v) to the composition of prehydrolyzate and the enzymatic hydrolysis. The results indicated that the maximum xylose yields in prehydrolyzate liquid were 15.78 g (combined 3.16 g xylose and 12.62 g xylo-oligosaccharides per 100g raw material). Due to the effective removal of hemicellulose, the maximum glucose yield in enzyme hydrolyzate reached 37.99 g per 100g raw material, representing 91.87% of glucose in the sugarcane bagasse. The maximal total sugars yield (combined xylose and glucose both in prehydrolyzate and enzymatic hydrolyzate) were 52.95 g based on 100g raw material. These results indicated that subcritical CO2 pretreatment can effectively improve the enzymatic hydrolysis, so it could be successfully applied to sugarcane bagasse. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. [Effect of Tween 80 and rhamnolipid on enzymatic hydrolysis of straw].

    PubMed

    Mo, Dan; Yuan, Xing-Zhong; Zeng, Guang-Ming; Liu, Jia

    2008-07-01

    The method of enzymatic hydrolysis was adopted and straw was used as substrate to study the effects of reducing sugar yield, enzyme stability and convention rate of cellulose during the course of enzymatic hydrolysis as well as the impacts of enzyme kinetic characteristics and adsorption of cellulase on cellulose by addition of chemical-surfactant Tween 80 and biosurfactant rhamnolipid. The results indicated that Tween 80 and rhamnolipid at different concentrations enhanced the production of reducing sugar. Tween 80 at 0.016% and 0.048% increased reducing sugar yield by 18.07% and 11.98%, while rhamnolipid at 0.01% and 0.03% increased reducing sugar yield by 23.01% and 22.16%, respectively. It can be seen from the experimental results that surfactants improved enzyme stability availably. Surfactants at high concentrations were superior to those at low concentrations in enzyme stability. Tween 80 at 0.048% obtained maximal relative carboxymethylcellulose activity (CMCA) 108.06% and maximal relative filter paper activity (FPA) 80.26%. Surfactants also enhanced conversion rate of cellulose, and that in the present of rhamnolipid, the percent conversion of cellulose was higher than those with Tween 80 distinctly. Moreover, surfactants not only promoted maximal velocity of enzymatic reaction and largened Michaelis constant but also reduced adsorption of cellulase on cellulose remarkably.

  9. Influence of pretreatment condition on the fermentable sugar production and enzymatic hydrolysis of dilute acid-pretreated mixed softwood.

    PubMed

    Lim, Woo-Seok; Lee, Jae-Won

    2013-07-01

    In this study, the effects of different acid catalysts and pretreatment factors on the hydrolysis of mixed softwood were investigated over a range of thermochemical pretreatments. Maleic, oxalic, and sulfuric acids were each used, under different pretreatment conditions. The most influential factor for fermentable sugar production in the dicarboxylic acid pretreatment of softwood was the pH. Reaction temperature was the next significant factor. However, during sulfuric acid pretreatment, fermentable sugar production was more dependent on reaction temperature, than time or pH. Enzymatic hydrolysis yields differed, depending on acid catalyst and pretreatment factor, regardless of lignin content in pretreated biomass. The highest enzymatic hydrolysis yield was found following maleic acid pretreatment, which reached 61.23%. The trend in enzymatic hydrolysis yields that were detected concomitantly with pretreatment condition or type of acid catalyst was closely related to the fermentable sugar production in the hydrolysate. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

  10. Real-time monitoring of enzymatic DNA hydrolysis by electrospray ionization mass spectrometry.

    PubMed

    van den Heuvel, Robert H H; Gato, Sara; Versluis, Cees; Gerbaux, Pascal; Kleanthous, Colin; Heck, Albert J R

    2005-06-13

    A fast and direct method for the monitoring of enzymatic DNA hydrolysis was developed using electrospray ionization mass spectrometry. We incorporated the use of a robotic chip-based electrospray ionization source for increased reproducibility and throughput. The mass spectrometry method allows the detection of DNA fragments and intact non-covalent protein-DNA complexes in a single experiment. We used the method to monitor in real-time single-stranded (ss) DNA hydrolysis by colicin E9 DNase and to characterize transient non-covalent E9 DNase-DNA complexes present during the hydrolysis reaction. The mass spectra showed that E9 DNase interacts with ssDNA in the absence of a divalent metal ion, but is strictly dependent on Ni2+ or Co2+ for ssDNA hydrolysis. We demonstrated that the sequence selectivity of E9 DNase is dependent on the ratio protein:ssDNA or the ssDNA concentration and that only 3'-hydroxy and 5'-phosphate termini are produced. It was also shown that the homologous E7 DNase is reactive with Zn2+ as transition metal ion and that this DNase displays a different sequence selectivity. The method described is of general use to analyze the reactivity and specificity of nucleases.

  11. Does densification influence the steam pretreatment and enzymatic hydrolysis of softwoods to sugars?

    PubMed

    Kumar, Linoj; Tooyserkani, Zahra; Sokhansanj, Shahab; Saddler, Jack N

    2012-10-01

    The global trade in wood pellets continues to grow. However, their potential as a feedstock for large scale cellulosic ethanol production has not been evaluated. We anticipated that the reduced moisture content and pressure exerted on the wood biomass during the pelletisation process would result in some carbohydrate loss as well as making the biomass more recalcitrant to pretreatment and subsequent hydrolysis. However, when softwood chips and pellets were steam pretreated at medium severity, little hemicellulose loss occurred while more than two-thirds of the cellulose present in the cellulose rich water insoluble fractions were hydrolysed (at 20 FPU cellulase/g cellulose). In addition, prior steaming substantially reduced the particle size of the wood chips enabling direct pelletisation without the need for grinding. Surprisingly, it was also possible to apply a single steam pretreatment to facilitate both pelletisation and subsequent enzymatic hydrolysis without the need for a further pretreatment step.

  12. Preparation and characterization of molecular weight fractions of guar galactomannans using acid and enzymatic hydrolysis.

    PubMed

    Cheng, Yu; Brown, Kirk M; Prud'homme, Robert K

    2002-12-20

    A procedure is described for the preparation of large amounts of guar galactomannan by acid hydrolysis that yields samples of various molecular weights (MW) with uniform polydispersity. This contrasts with preparation by enzymatic degradation that yields samples with a marked increase in polydispersity and a much broader molecular weight distribution (MWD). Acid hydrolyzed guar samples had a Mark-Houwink-Sakurada (MHS) relationship of [eta]=3.04x10(-4) M(w)(0.747) dl/g and a characteristic ratio of 11.87 as determined by gel permeation chromatography (GPC) and dilute solution viscometry. The Huggins coefficient for degraded guars is much smaller (approximately 0.4) than that of the native guar (approximately 0.79), suggesting a weakening of intermolecular association in guar prepared by acid hydrolysis.

  13. Membrane-based recovery of glucose from enzymatic hydrolysis of ionic liquid pretreated cellulose.

    PubMed

    Abels, Christian; Thimm, Kristof; Wulfhorst, Helene; Spiess, Antje Christine; Wessling, Matthias

    2013-12-01

    In this work, a membrane-based downstream process for the recovery of glucose from cellulose hydrolysis is described and evaluated. The cellulose is pretreated with the ionic liquid 1,3-dimethyl-imidazolium dimethylphosphate to reduce its crystallinity. After enzymatic conversion of cellulose to glucose the hydrolysate is filtered with an ultrafiltration membrane to remove residual particulates and enzymes. Nanofiltration is applied to purify the glucose from molecular intermediates, such as cellobiose originating from the hydrolysis reaction. Finally, the ionic liquid is removed from the hydrolysate via electrodialysis. Technically, these process steps are feasible. An economic analysis of the process reveals that the selling price of glucose from this production process is about 2.75 €/kg which is too high as compared to the current market price.

  14. Enzymatic hydrolysis of pelletized AFEX™-treated corn stover at high solid loadings.

    PubMed

    Bals, Bryan D; Gunawan, Christa; Moore, Janette; Teymouri, Farzaneh; Dale, Bruce E

    2014-02-01

    Ammonia fiber expansion (AFEX™) pretreatment can be performed at small depots, and the pretreated biomass can then be pelletized and shipped to a centralized refinery. To determine the feasibility of this approach, pelletized AFEX-treated corn stover was hydrolyzed at high (18-36%) solid loadings. Water absorption and retention by the pellets was low compared to unpelletized stover, which allowed enzymatic hydrolysis slurries to remain well mixed without the need for fed-batch addition. Glucose yields of 68% and xylose yields of 65% were obtained with 20 mg enzyme/g glucan and 18% solid loading after 72 h, compared to 61% and 59% for unpelletized corn stover. Pelletization also slightly increased the initial rate of hydrolysis compared to unpelletized biomass. The ease of mixing and high yields obtained suggests that pelletization after AFEX pretreatment could have additional advantages beyond improved logistical handling of biomass.

  15. Synthesis, opioid receptor affinity, and enzymatic hydrolysis of sterically hindered morphine 3-esters.

    PubMed

    Mignat, C; Heber, D; Schlicht, H; Ziegler, A

    1996-07-01

    With the intention of preparing prodrugs, 10 morphine 3-esters were synthesized and evaluated in vitro for opioid receptor binding and enzymatic hydrolysis. The results of binding assays performed on homogenates of guinea pig brain demonstrate a loss in affinity of morphine to mu-, delta-, and kappa-receptors by esterification at the 3-position. The conversion of the esters to morphine was determined in human plasma by HPLC analysis. The half-lives of hydrolysis ranged from 0.5 to > 300 h. The investigations indicate that esterification at the 3-position results in morphine prodrugs with variable hydrolytic stability. Sterically hindered morphine 3-esters may be a promising approach to manipulate the rate of release of morphine.

  16. Pulp properties resulting from different pretreatments of wheat straw and their influence on enzymatic hydrolysis rate.

    PubMed

    Rossberg, Christine; Steffien, Doreen; Bremer, Martina; Koenig, Swetlana; Carvalheiro, Florbela; Duarte, Luís C; Moniz, Patrícia; Hoernicke, Max; Bertau, Martin; Fischer, Steffen

    2014-10-01

    Wheat straw was subjected to three different processes prior to saccharification, namely alkaline pulping, natural pulping and autohydrolysis, in order to study their effect on the rate of enzymatic hydrolysis. Parameters like medium concentration, temperature and time have been varied in order to optimize each method. Milling the raw material to a length of 4mm beforehand showed the best cost-value-ratio compared to other grinding methods studied. Before saccharification the pulp can be stored in dried form, leading to a high yield of glucose. Furthermore the relation of pulp properties (i.e. intrinsic viscosity, Klason-lignin and hemicelluloses content, crystallinity, morphology) to cellulose hydrolysis is discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Model-Based Fed-Batch for High-Solids Enzymatic Cellulose Hydrolysis

    SciTech Connect

    Hodge, D. B.; Karim, M. N.; Schell, D. J.; McMillan, J. D.

    2008-01-01

    While many kinetic models have been developed for the enzymatic hydrolysis of cellulose, few have been extensively applied for process design, optimization, or control. High-solids operation of the enzymatic hydrolysis of lignocellulose is motivated by both its operation decreasing capital costs and increasing product concentration and hence separation costs. This work utilizes both insights obtained from experimental work and kinetic modeling to develop an optimization strategy for cellulose saccharification at insoluble solids levels greater than 15% (w/w), where mixing in stirred tank reactors (STRs) becomes problematic. A previously developed model for batch enzymatic hydrolysis of cellulose was modified to consider the effects of feeding in the context of fed-batch operation. By solving the set of model differential equations, a feeding profile was developed to maintain the insoluble solids concentration at a constant or manageable level throughout the course of the reaction. Using this approach, a stream of relatively concentrated solids (and cellulase enzymes) can be used to increase the final sugar concentration within the reactor without requiring the high initial levels of insoluble solids that would be required if the operation were performed in batch mode. Experimental application in bench-scale STRs using a feed stream of dilute acid-pretreated corn stover solids and cellulase enzymes resulted in similar cellulose conversion profiles to those achieved in batch shake-flask reactors where temperature control issues are mitigated. Final cellulose conversions reached approximately 80% of theoretical for fed-batch STRs fed to reach a cumulative solids level of 25% (w/w) initial insoluble solids.

  18. Polyol Structure Influences Enzymatic Hydrolysis of Bio-Based 2,5-Furandicarboxylic Acid (FDCA) Polyesters.

    PubMed

    Haernvall, Karolina; Zitzenbacher, Sabine; Amer, Hassan; Zumstein, Michael T; Sander, Michael; McNeill, Kristopher; Yamamoto, Motonori; Schick, Michael B; Ribitsch, Doris; Guebitz, Georg M

    2017-09-01

    Polyesters of 2,5-furandicarboxylic acid (FDCA) have gained attention as they can be regarded as the bio-based alternatives to the petroleum-based polyesters of terephthalic acid. However, only little is known about the biodegradation and enzymatic hydrolysis of FDCA-based polyesters. This work aims to investigate the influence of different polyols on enzymatic hydrolysis of FDCA-based polyesters. A series of polyesters containing various polyols are synthesized and analyzed regarding susceptibility to enzymatic hydrolysis by cutinase 1 from Thermobifida cellulosilytica (Thc_Cut1). FDCA-based polyesters' number average molecular weight (Mn ) ranged from 9360-35 800 g mol(-1) according to gel permeation chromatography (GPC) analysis. Differential scanning calorimetry (DSC) analyses show decreasing glass transition temperature (Tg ) with increasing diol chain length. Crystallinity of all polyesters is below 1% except for polyesters containing 1,6-hexanediol, 1,8-octanediol, and 1,12-dodecanediol for which calculated crystallinities are 27, 37, and 30%, respectively. Thc_Cut1 hydrolyzes all tested polyesters with preference for polyesters containing 1,5-pentanediol and 1,9-nonanediol (57.7 ± 7.5 and 52.8 ± 4.0% released FDCA). Enzyme activity increases when the linear diol 1,3-propanediol is replaced by the branched analog 1,2-propanediol or ethoxy units are introduced into the polyester chain. The results will contribute to expand the knowledge of microbial biodegradation of FDCA-based polyesters. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Assessment of Taste Attributes of Peanut Meal Enzymatic-Hydrolysis Hydrolysates Using an Electronic Tongue

    PubMed Central

    Wang, Li; Niu, Qunfeng; Hui, Yanbo; Jin, Huali; Chen, Shengsheng

    2015-01-01

    Peanut meal is the byproduct of high-temperature peanut oil extraction; it is mainly composed of proteins, which have complex tastes after enzymatic hydrolysis to free amino acids and small peptides. The enzymatic hydrolysis method was adopted by using two compound proteases of trypsin and flavorzyme to hydrolyze peanut meal aiming to provide a flavor base. Hence, it is necessary to assess the taste attributes and assign definite taste scores of peanut meal double enzymatic hydrolysis hydrolysates (DEH). Conventionally, sensory analysis is used to assess taste intensity in DEH. However, it has disadvantages because it is expensive and laborious. Hence, in this study, both taste attributes and taste scores of peanut meal DEH were evaluated using an electronic tongue. In this regard, the response characteristics of the electronic tongue to the DEH samples and standard five taste samples were researched to qualitatively assess the taste attributes using PCA and DFA. PLS and RBF neural network (RBFNN) quantitative prediction models were employed to compare predictive abilities and to correlate results obtained from the electronic tongue and sensory analysis, respectively. The results showed that all prediction models had good correlations between the predicted scores from electronic tongue and those obtained from sensory analysis. The PLS and RBFNN prediction models constructed using the voltage response values from the sensors exhibited higher correlation and prediction ability than that of principal components. As compared with the taste performance by PLS model, that of RBFNN models was better. This study exhibits potential advantages and a concise objective taste assessment tool using the electronic tongue in the assessment of DEH taste attributes in the food industry. PMID:25985162

  20. [Effects of hot-NaOH pretreatment on Jerusalem artichoke stalk composition and subsequent enzymatic hydrolysis].

    PubMed

    Wang, Qing; Qiu, Jingwen; Li, Yang; Shen, Fei

    2015-10-01

    In order to explore the possibility of Jerusalem artichoke stalk for bioenergy conversion, we analyzed the main composition of whole stalk, pitch, and core of the stalk. Meanwhile, these parts were pretreated with different NaOH concentrations at 121 degrees C. Afterwards, enzymatic hydrolysis was performed to evaluate the pretreatment efficiency. Jerusalem artichoke stalk was characterized by relatively high lignin content (32.0%) compared with traditional crop stalks. The total carbohydrate content was close to that of crop stalks, but with higher cellulose content (40.5%) and lower hemicellulose (19.6%) than those of traditional crop stalks. After pretreatment, the lignin content in the whole stalk, pitch, and core decreased by 13.1%-13.4%, 8.3%-13.5%, and 19.9%-27.2%, respectively, compared with the unpretreated substrates. The hemicellulose content in the whole stalk, pitch, and core decreased 87.8%-96.9%, 87.6%-95.0%, and 74.0%-90.2%, respectively. Correspondingly, the cellulose content in the pretreated whole stalk, pitch, and core increased by 56.5%-60.2%, 52.2%-55.4%, and 62.7%-73.2%, respectively. Moreover, increase of NaOH concentration for pretreatment could improve the enzymatic hydrolysis of the whole stalk and pitch by 2.3-2.6 folds and 10.3-18.5 folds, respectively. The hydrolysis of pretreated stalk core decreased significantly as 2.0 mol/L NaOH was employed, although the increased NaOH concentration can also improve its hydrolysis performance. Based on these results, hot-NaOH can be regarded as an option for Jerusalem artichoke stalk pretreatment. Increasing NaOH concentration was beneficial to hemicellulose and lignin removal, and consequently improved sugar conversion. However, the potential decrease of sugar conversion of the pretreated core by higher NaOH concentration suggested further optimization on the pretreatment conditions should be performed.

  1. Extracting xylooligosaccharides in wheat bran by screening and cellulase assisted enzymatic hydrolysis.

    PubMed

    Zhao, Xiaoqing; Dong, Cao

    2016-11-01

    Functional xylooligosaccharides (XOS) from wheat bran were carried out by screening and cellulase assisted enzymatic hydrolysis. First, wheat bran was crushed and screened, getting the optimal experimental particle size of raw materials (>125μm), and 72.43% of starch. Wheat bran was then repeated colloid milled and hydrolysed with cellulase, releasing about 45% of xylan (higher than the untreated wheat bran (about 29%)). Finally, membrane treatment (20kDa and 1kDa cutoff) was chosen to eliminate impurities and enriched XOS. In the designed process, 51mg purified XOS was obtained from 1g dry wheat bran powder.

  2. Enzymatic hydrolysis of organic-core microcapsules to produce aqueous-core microcapsules.

    PubMed

    Breguet, Veronique; Vojinovic, Vojislav; Von Stockar, Urs; Marison, Ian W

    2008-05-01

    This paper describes the development of a new method to obtain aqueous-core microcapsules from organic-core capsules. The direct production of microcapsules, using tripropionin as organic material, followed by the hydrolysis of the core by a lipase was investigated. The enzymatic study showed that the enzyme obeyed a Michaelis-Menten mechanism and conditions for optimal activity were pH 7.5, 25-37 degrees C and 0% NaCl. Under these conditions, incubation of tripropionin-alginate microcapsules in a buffer containing the enzyme successfully produced aqueous-core capsules with reduced accumulation of alginate in the core in approximately 3 h.

  3. Microalgae pretreatment with liquid hot water to enhance enzymatic hydrolysis efficiency.

    PubMed

    Yuan, Tao; Li, Xiekun; Xiao, Shiyuan; Guo, Ying; Zhou, Weizheng; Xu, Jingliang; Yuan, Zhenhong

    2016-11-01

    Nowadays, microalgae are being considered as promising raw material for bioethanol production. In this work, three process variables during liquid hot water (LHW) pretreatment prior to enzymatic hydrolysis by response surface methodology on Scenedesmus sp. WZKMT were investigated to enhance glucose recovery. Results indicated that the order of significance for three parameters was temperature>solid-to-liquid ratio>time. The optimal condition was 1:13 (w/v), 147°C and 40min. The concentration and recovery of glucose under this condition were 14.223g·L(-1) and 89.32%, respectively, which were up to 5-fold higher than the samples without LHW pretreatment. In addition, the surface morphologies of microalgae cells before and after LHW pretreatment were also verified using scanning electron microscopy (SEM). LHW pretreatment can greatly enhance the enzymatic efficiency, and can be regarded as an ideal pretreatment method for glucose recovery from microalgae.

  4. Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry

    NASA Astrophysics Data System (ADS)

    Dors, Gisanara; Mendes, Adriano A.; Pereira, Ernandes B.; de Castro, Heizir F.; Furigo, Agenor

    2013-03-01

    Simultaneous enzymatic hydrolysis and anaerobic biodegradation of lipid-rich wastewater from poultry industry with porcine pancreatic lipase at different concentrations (from 1.0 to 3.0 g L-1) were performed. The efficiency of the enzymatic pretreatment was measured by the Chemical Oxygen Demand (COD) removal and formation of methane. All samples pretreated with lipase showed a positive effect on the COD removal and formation of methane. After 30 days of anaerobic biodegradation the methane production varied from 569 ± 95 to 1,101 ± 10 mL for crude wastewater and pretreated at 3.0 g L-1 enzyme, respectively. COD removal of wastewater supplemented at different enzyme concentrations was found to be threefold higher than crude wastewater. The use of lipases seems to be a promising alternative for treating lipid-rich wastewaters such as those from the poultry industry.

  5. High-Throughput Analysis of Enzymatic Hydrolysis of Biodegradable Polyesters by Monitoring Cohydrolysis of a Polyester-Embedded Fluorogenic Probe.

    PubMed

    Zumstein, Michael Thomas; Kohler, Hans-Peter E; McNeill, Kristopher; Sander, Michael

    2017-02-14

    Biodegradable polyesters have the potential to replace nondegradable, persistent polymers in numerous applications and thereby alleviate plastic accumulation in the environment. Herein, we present an analytical approach to study enzymatic hydrolysis of polyesters, the key step in their overall biodegradation process. The approach is based on embedding fluorescein dilaurate (FDL), a fluorogenic ester substrate, into the polyester matrix and on monitoring the enzymatic cohydrolysis of FDL to fluorescein during enzymatic hydrolysis of the polyester. We validated the approach against established techniques using FDL-containing poly(butylene adipate) films and Fusarium solani cutinase (FsC). Implemented on a microplate reader platform, the FDL-based approach enabled sensitive and high-throughput analysis of the enzymatic hydrolysis of eight aliphatic polyesters by two fungal esterases (FsC and Rhizopus oryzae lipase) at different temperatures. While hydrolysis rates for both enzymes increased with decreasing differences between the polyester melting temperatures and the experimental temperatures, this trend was more pronounced for the lipase than the cutinase. These trends in rates could be ascribed to a combination of temperature-dependent polyester chain flexibility and accessibility of the enzyme active site. The work highlights the capability of the FDL-based approach to be utilized in both screening and mechanistic studies of enzymatic polyester hydrolysis.

  6. Effect of the molecular structure of lignin-based polyoxyethylene ether on enzymatic hydrolysis efficiency and kinetics of lignocelluloses.

    PubMed

    Lin, Xuliang; Qiu, Xueqing; Zhu, Duming; Li, Zihao; Zhan, Ningxin; Zheng, Jieyi; Lou, Hongming; Zhou, Mingsong; Yang, Dongjie

    2015-10-01

    Effect of the molecular structure of lignin-based polyoxyethylene ether (EHL-PEG) on enzymatic hydrolysis of Avicel and corn stover was investigated. With the increase of PEG contents and molecular weight of EHL-PEG, glucose yield of corn stover increased. EHL-PEG enhanced enzymatic hydrolysis of corn stover significantly at buffer pH 4.8-5.5. Glucose yield of corn stover at 20% solid content increased from 32.8% to 63.8% by adding EHL-PEG, while that with PEG4600 was 54.2%. Effect of EHL-PEG on enzymatic hydrolysis kinetics of cellulose film was studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). An enhancing mechanism of EHL-PEG on enzymatic hydrolysis kinetics of cellulose was proposed. Cellulase aggregates dispersed by EHL-PEG excavated extensive cavities into the surface of cellulose film, making the film become more loose and exposed. After the maximum enzymatic hydrolysis rate, the film was mainly peeled off layer by layer until equilibrium.

  7. Suitable technological conditions for enzymatic hydrolysis of waste paper by Novozymes® enzymes NS50013 and NS50010.

    PubMed

    Brummer, Vladimir; Skryja, Pavel; Jurena, Tomas; Hlavacek, Viliam; Stehlik, Petr

    2014-10-01

    Waste paper belongs to a group of quantitatively the most produced waste types. Enzymatic hydrolysis is becoming a suitable way to treat this type of waste and at the same time, to produce a valuable liquid biofuel, because reducing sugars solutions that are formed during the process of saccharification can be a precursor for following or simultaneous fermentation. If it will be possible to make the enzymatic hydrolysis of the waste paper economically viable, it could serve as one of the new ways to lower the dependence of the transport sector on oil in the future. Only several studies comparing the enzymatic hydrolysis of different waste papers were performed in the past; they are summarized in this manuscript. In our experimental trials, suitable technological conditions for waste paper enzymatic hydrolysis using enzymes from Novozymes® biomass kit: enzymes NS50013 and NS50010 were investigated. The following enzymatic hydrolysis parameters in laboratory scale trials were verified on high cellulose content substrates-filter paper and cellulose pulp: type of buffer, pH, temperature, concentration of the substrate, loading of the enzyme and rate of stirring.

  8. Optimization of enzymatic hydrolysis conditions for extraction of pectin from rapeseed cake (Brassica napus L.) using commercial enzymes.

    PubMed

    Jeong, Han-Seob; Kim, Ho-Yong; Ahn, Sye Hee; Oh, Sei Chang; Yang, In; Choi, In-Gyu

    2014-08-15

    The aims of this study were to extract pectin from rapeseed cake (RSC) by enzymatic hydrolysis using commercial enzymes (Celluclast and Alcalase) and to investigate the effects of different reaction conditions, such as enzymatic hydrolysis time, enzyme-RSC ratio, and Celluclast-Alcalase ratio, on the degradation of RSC and pectin yield. RSC was treated using a combined extraction process that consisted of a fat removal process, enzymatic hydrolysis, and isopropanol/ethanol precipitation. After the fat removal process and enzymatic hydrolysis, defatted-RSC was suitably decomposed, and the loss of liberated reducing sugars was minimized when the hydrolysis condition reached a hydrolysis time of 270 min or an enzyme-RSC ratio of 1:50. Based on these results, various Celluclast-Alcalase ratios were applied. Alcalase led to the destruction of protein-carbohydrate complex in defatted-RSC, whereas Celluclast cleaved some linkages of carbohydrate slightly. As a result, the highest pectin yield was 6.85% at the Celluclast-Alcalase ratio of 1:4.

  9. Extraction of cellulose nano-crystals from old corrugated container fiber using phosphoric acid and enzymatic hydrolysis followed by sonication.

    PubMed

    Tang, Yanjun; Shen, Xiaochuang; Zhang, Junhua; Guo, Daliang; Kong, Fangong; Zhang, Nan

    2015-07-10

    Due to its amazing physicochemical properties and high environmental compatibility, cellulose nano-crystals (CNC) hold great promise for serving as a strategic platform for sustainable development. Now, there has been growing interest in the development of processes using waste or residual biomass as CNC source for addressing economic and environmental concerns. In the present work, a combined process involving phosphoric acid hydrolysis, enzymatic hydrolysis and sonication was proposed aiming to efficiently exact CNC from low-cost old corrugated container (OCC) pulp fiber. The effect of enzymatic hydrolysis on the yield and microstructure of resulting CNC was highlighted. Results showed that the enzymatic hydrolysis was effective in enhancing CNC yield after phosphoric acid hydrolysis. CNC was obtained with a yield of 23.98 wt% via the combined process with phosphoric acid concentration of 60 wt%, cellulase dosage of 2 mL (84 EGU) per 2g fiber and sonication intensity of 200 W. Moreover, the presence of enzymatic hydrolysis imparted the obtained CNC with improved dispersion, increased crystallinity and thermal stability.

  10. High activity cellulase production by recombinant Trichoderma reesei ZU-02 with the enhanced cellobiohydrolase production.

    PubMed

    Fang, Hao; Xia, Liming

    2013-09-01

    The cbh1 strong promoter was employed to over-express the cbh2 gene for enhancing cellobiohydrolase (CBH) production in Trichoderma reesei because CBH II component has higher specific activity than CBH I and is an important component in cellulase. The recombinant plasmid pCAMBIA1300-hph-PsCT containing strong expression cassette was constructed and transformed into T. reesei via optimized Agrobacterium-mediated transformation, producing 324 positive T. reesei transformants for the two steps of screening. Ten fast-growing T. reesei transformants were selected, amongst which C10 was found to have the highest filter paper activity 28.92±2.45 IU/mL, 4.3-fold higher than that of ZU-02, 6.71±0.79 IU/mL. C10 also has the highest cellobiohydrolase activity 122.44±7.42 U/mL, 5.4 times higher than that of ZU-02, 22.49±2.27 U/mL. The cellulase from C10 performed better (93.06±2.83%) than the one from ZU-02 in enzymatic hydrolysis because the exo-exo-synergism played a role.

  11. A process for reduction in viscosity of coffee extract by enzymatic hydrolysis of mannan.

    PubMed

    Chauhan, Prakram Singh; Sharma, Prince; Puri, Neena; Gupta, Naveen

    2014-07-01

    Mannan is the main polysaccharide component of coffee extract and is responsible for its high viscosity, which in turn negatively affects the technological processing involved in making instant coffee. In our study, we isolated mannan from coffee beans and extract of commercial coffee and it was enzymatically hydrolyzed using alkali-thermostable mannanase obtained from Bacillus nealsonii PN-11. As mannan is found to be more soluble under alkaline conditions, an alkali-thermostable mannanase is well suited for its hydrolysis. The process of enzymatic hydrolysis was optimized by response surface methodology. Under the following optimized conditions viz enzyme dose of 11.50 U mannanase g(-1) coffee extract, temperature of 44.50 °C and time of 35.80 min, significant twofold decrease in viscosity (50 mPas to 26.00 ± 1.56 mPas) was achieved. The application of this process in large-scale industrial production of coffee will help in reduction of energy consumption used during freeze-drying. It will also make technological processing involved in making coffee more economical.

  12. Kinetic modeling of rapid enzymatic hydrolysis of crystalline cellulose after pretreatment by NMMO.

    PubMed

    Khodaverdi, Mahdi; Jeihanipour, Azam; Karimi, Keikhosro; Taherzadeh, Mohammad J

    2012-03-01

    Pretreatment of cellulose with an industrial cellulosic solvent, N-methylmorpholine-N-oxide, showed promising results in increasing the rate of subsequent enzymatic hydrolysis. Cotton linter was used as high crystalline cellulose. After the pretreatment, the cellulose was almost completely hydrolyzed in less than 12 h, using low enzyme loading (15 FPU/g cellulose). The pretreatment significantly decreased the total crystallinity of cellulose from 7.1 to 3.3, and drastically increased the enzyme adsorption capacity of cellulose by approximately 42 times. A semi-mechanistic model was used to describe the relationship between the cellulose concentration and the enzyme loading. In this model, two reactions for heterogeneous reaction of cellulose to glucose and cellobiose, and a homogenous reaction for cellobiose conversion to glucose was incorporated. The Langmuir model was applied to model the adsorption of cellulase onto the treated cellulose. The competitive inhibition was also considered for the effects of sugar inhibition on the rate of enzymatic hydrolysis. The kinetic parameters of the model were estimated by experimental results and evaluated.

  13. Enhancement of enzymatic hydrolysis and lignin removal of bagasse using photocatalytic pretreatment

    NASA Astrophysics Data System (ADS)

    Pattanapibul1, P.; Chuangchote, S.; Laosiripojana, N.; Champreda, V.; Kaewsaenee, J.

    2017-05-01

    Pretreatment for reduction of biological resistance in a lignocellulosic material, i.e. bagasse, for enzymatic hydrolysis and fermentation was investigated. Photocatalyst (TiO2) was used as an additive composition to assist this pretreatment process. Reaction time was varied (24, 48, and 72 h) to find the optimum condition for the pretreatment, while concentration of solvent (NaOH, H2O2, or NH4OH), biomass to solvent ratio, and weight ratio of catalyst to bagasse were fixed at 2 M, 1:20 g/ml (typically, solvent = 150 ml), and 1:5, respectively. Batch reaction temperature was at 25°C. After the pretreatment, the enzymatic digestibility of pretreated bagasse was carried out to find the sugar yield. Hydrolysis of pretreated bagasse with photocatalyst show higher sugar yields than the conventional reactions without photocatalyst. The maximum yields of sugars (541.03 mg glucose and 192.79 mg pentose) were obtained at the longest reaction time.

  14. Topochemical pretreatment of wood biomass to enhance enzymatic hydrolysis of polysaccharides to sugars.

    PubMed

    Mou, Hong-Yan; Orblin, Elina; Kruus, Kristiina; Fardim, Pedro

    2013-08-01

    The surface chemistry of milled birch and pine wood pretreated by ionic liquid, hydrothermal and hydrotropic methods, followed by enzymatic hydrolysis was studied in this work. Surface coverage by lignin was measured by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) was used to describe the surface chemical composition after pretreatment in detail, and the morphology after pretreatment was investigated by FE-SEM. Ionic liquid (1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride) pretreatment at room temperature made the samples swell but did not dissolve the wood. Comparing the surface coverage by lignin, both in the case of birch and pine wood, hydrotropic worked best to remove the lignin hampering enzymatic hydrolysis. ToF-SIMS supported this finding, and showed that in birch, the carbohydrates were degraded more than in pine after hydrotropic pretreatment. The glucose yield of birch was improved by hydrotropic pretreatment from 5.1% to 83.9%, more significantly than in case of pine.

  15. [Role of genistein in enzymatic albumin hydrolysis in the presence of nitrates (III) and (V)].

    PubMed

    Tokarz, Andrzej; Pokorska-Lis, Grazyna; Popiel, Elzbieta

    2008-01-01

    Polyphenols and nitrates are essential ingredients of human diet. Harm caused by nitrates is well know and studied. Positive role of polyphenols is investigated. The aim of the study was to analyze interactions between nitrates (III) and (V) and genistein in systems of enzymatic protein (albumin) hydrolysis. In vitro model of enzymatic acidic-alkaline albumine hydrolysis in the presence of nitrates, polyphenols and vitamin C in different concentrations was used. Content of nitrates was measured in dialysation fluid spectrophotometrically according to Griess' method. The study revealed inhibiting influence of genistein on nitrares(III) concentration in external compartment. The influence depended on polyphenol dose (for nitrates (III) between 11.21% and 7.27%, for nitrates (V) between 95.64% and 79.64% of dialysis). When genistein was introduced in too high concentrations--over 2,4 mg/system--it did not improve the effect, but inhibited it. The influence of genistein was synergic with resveratrol and vitamin C.

  16. Dilute acid pretreatment and enzymatic hydrolysis of sorghum biomass for sugar recovery--a statistical approach.

    PubMed

    Akanksha, Karthik; Prasad, Arjun; Sukumaran, Rajeev K; Nampoothiri, Madhavan; Pandey, Ashok; Rao, S S; Parameswaran, Binod

    2014-11-01

    Sorghum is one of the commercially feasible lignocellulosic biomass and has a great potential of being sustainable feedstock for renewable energy. As with any lignocellulosic biomass, sorghum also requires pretreatment which increases its susceptibility to hydrolysis by enzymes for generating sugars which can be further fermented to alcohol. In the present study, sorghum biomass was evaluated for deriving maximum fermentable sugars by optimizing various pretreatment parameters using statistical optimization methods. Pretreatment studies were done with H2SO4, followed by enzymatic saccharification. The efficiency of the process was evaluated on the basis of production of the total reducing sugars released during the process. Compositional analysis was done for native as well as pretreated biomass and compared. The biomass pretreated with the optimized conditions could yield 0.408 g of reducing sugars /g of pretreated biomass upon enzymatic hydrolysis. The cellulose content in the solid portion obtained after pretreatment using optimised conditions was found to be increased by 43.37% with lesser production of inhibitors in acid pretreated liquor.

  17. Enzymatic Hydrolysis Optimization to Ethanol Production by Simultaneous Saccharification and Fermentation

    NASA Astrophysics Data System (ADS)

    Vásquez, Mariana Peñuela; da Silva, Juliana Nascimento C.; de Souza, Maurício Bezerra; Pereira, Nei

    There is tremendous interest in using agro-industrial wastes, such as cellulignin, as starting materials for the production of fuels and chemicals. Cellulignin are the solids, which result from the acid hydrolysis of the sugarcane bagasse. The objective of this work was to optimize the enzymatic hydrolysis of the cellulose fraction of cellulignin, and to study its fermentation to ethanol using Saccharomyces cerevisiae. Cellulose conversion was optimized using response surface methods with pH, enzyme loading, solid percentage, and temperature as factor variables. The optimum conditions that maximized the conversion of cellulose to glucose, calculated from the initial dried weight of pretreated cellulignin, (43°C, 2%, and 24.4 FPU/g of pretreated cellulignin) such as the glucose concentration (47°C, 10%, and 25.6 FPU/g of pretreated cellulignin) were found. The desirability function was used to find conditions that optimize both, conversion to glucose and glucose concentration (47°C, 10%, and 25.9 FPU/g of pretreated cellulignin). The resulting enzymatic hydrolyzate was fermented yielding a final ethanol concentration of 30.0 g/L, in only 10 h, and reaching a volumetric productivity of 3.0 g/L·h, which is close to the values obtained in the conventional ethanol fermentation of sugar cane juice (5.0-8.0 g/L·h) in Brazil.

  18. Feasibility of reusing the black liquor for enzymatic hydrolysis and ethanol fermentation.

    PubMed

    Wang, Wen; Chen, Xiaoyan; Tan, Xuesong; Wang, Qiong; Liu, Yunyun; He, Minchao; Yu, Qiang; Qi, Wei; Luo, Yu; Zhuang, Xinshu; Yuan, Zhenhong

    2017-03-01

    The 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 13.23 to 4.80 with acetic acid, and the alkaline lignin was partially precipitated. It deposited on the surface of cellulose and negatively influenced the EHC via blocking the access of cellulase to cellulose and adsorbing cellulase. The supernatant separated from the acidified BL scarcely affected the EHC, but inhibited the ethanol fermentation. The 4-times diluted supernatant and the last-time waste wash water of the alkali-treated sugarcane bagasse didn't inhibit the EHC and ethanol production. This work gives a clue of saving water for alkaline pretreatment.

  19. Optimization of clean fractionation process applied to switchgrass to produce pulp for enzymatic hydrolysis.

    PubMed

    Brudecki, Grzegorz; Cybulska, Iwona; Rosentrater, Kurt

    2013-03-01

    The purpose of this study was to fractionate switchgrass (SG) to obtain hemicellulose-, lignin-rich fractions and highly digestible pulp, using a clean fractionation (CF) approach. The main objective was to produce highest glucose yield in the enzymatic hydrolysis of pulp. Effects of processing factors such as time (10-50 min), temperature (120-160 °C), catalyst concentration (0.21-0.93% w/w sulfuric acid) and organic solvent mixture composition (7-43% w/w methyl isobutyl ketone) were evaluated. Response surface methodology and central composite design were used for process optimization and statistical analyses. High lignin (75-93%) and xylan (83-100%) removal from biomass were obtained, leaving solid pulp rich in glucan (78-94%). High enzymatic hydrolysis glucose yields (more than 90%) were obtained for selected optimal conditions. Pulp can be used for ethanol production while separated xylan and lignin fractions can be used as a feedstock for value-added products which suggests the applicability of clean fractionation technology in a biorefinery concept. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Sea buckthorn (Hippophae rhamnoides) proanthocyanidins inhibit in vitro enzymatic hydrolysis of protein.

    PubMed

    Arimboor, Ranjith; Arumughan, C

    2011-08-01

    Interactions of phenolics with other food constituents and digestive enzymes are likely to have interference with the digestion and bioavailability of food and phenolics. In this study the effect of sea buckthorn proanthocyanidins on in vitro digestion of protein was evaluated. Optimization of the extraction conditions showed that maximum recovery of sea buckthorn proanthocyanidins was obtained with acidified acetone; water mixture (60% to 70%, v/v). Crude proanthocyanidin extracts thus prepared were purified using sephadex gel column chromatography and their average degree of polymerization and the effects on enzymatic hydrolysis of bovine serum albumin as influenced by their protein precipitation capacities were studied. Average degree of polymerization of proanthocyanidins in berry pulp, kernel, seed coat, and leaves was 7.4, 5.6, 8.2, and 10.6, respectively. The EC50 values for the protein precipitation by the PA of berry pulp, kernel seed coat, and leaves were 44.2, 44.1, 65.8, and 39.8 μg, respectively. Relative enzymatic hydrolysis of the protein-proanthocyanidin complexes was 44.1% to 60.3% for pepsin and 57.5% to 67.7% for trypsin. Interactions of sea buckthorn proanthocyanidins with food proteins and digestive enzymes might alter the protein digestibility and phenolic bioavailabilty.

  1. Microbial pretreatment of corn stover with Ceriporiopsis subvermispora for enzymatic hydrolysis and ethanol production.

    PubMed

    Wan, Caixia; Li, Yebo

    2010-08-01

    The feasibility of concurrent wet storage and microbial pretreatment of corn stover with Ceriporiopsis subvermispora for ethanol production was investigated in this study. The effects of particle size (5-15 mm), moisture content (45-85%), pretreatment time (18-35 d), and temperature (4-37 degrees C) on lignin degradation and enzymatic hydrolysis yield were studied. The results showed that C. subvermispora selectively degraded lignin up to 31.59% with a limited cellulose loss of less than 6% during an 18-d pretreatment. When 5mm corn stover was pretreated at 28 degrees C with 75% moisture content, overall glucose yields of 57.67%, 62.21%, and 66.61% were obtained with 18-, 28-, and 35-d microbial pretreated corn stover, respectively. For the above conditions, the highest overall ethanol yield of 57.80% was obtained with 35-d-pretreated corn stover. Enzymatic hydrolysis yield was highly related to the lignin removal during microbial pretreatment.

  2. Brewer's spent grain: characterization and standardization procedure for the enzymatic hydrolysis by Bacillus cereus strain.

    PubMed

    Kotlar, Catalina E; Belagardi, Mariela; Roura, Sara I

    2011-01-01

    An important way to reuse agroindustrial by-products and to produce added-value products consists of the production of protein hydrolysates. In the current study, we used Brewer's spent grain (BSG), mainly because of its availability and cost, as a substrate for the enzymatic hydrolysis by Bacillus cereus. First, the physicochemical and microbiological characterization of BSG batches from three varieties was carried out. Furthermore, the optimal fermentation upstream processes for enzymatic hydrolysis by B. cereus were defined. Finally, the ability of B. cereus to hydrolyze different fractions of BSG was analyzed and possible synergistic effects of this bacterium along with other proteolytic bacteria were also investigated. Results showed that the naturally associated microflora was predominantly thermophilic aerobic bacteria and the drying process was the better alternative for BSG preservation. Water, lipids, and ash content differed significantly among the three varieties; however, no statistically significant differences were found in the protein content among them. After BSG characterization studies, the following protocol was set to obtain the fermentation substrate (FS): drying at 60°C for 24-48 H; sieving, grinding, and polyphenol extraction with an alcohol-water solution; and finally autoclaving. A synergistic effect was observed when B. cereus was inoculated with Pseudomonas strains in FS. Copyright © 2011 International Union of Biochemistry and Molecular Biology, Inc.

  3. Temperature sensitivity of cellulase adsorption on lignin and its impact on enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Zheng, Yingfu; Zhang, Songping; Miao, Shida; Su, Zhiguo; Wang, Ping

    2013-07-10

    Unproductive enzyme adsorption is an important factor in addition to steric hindrance of lignin that limits the enzymatic hydrolysis of lignocellulosic biomass. While both are important factors, enzymatic hydrolysis of pretreated biomass is most likely conducted in the presence of certain amount of lignin residues that may not necessarily present accessibility hindrance, but can competitively absorb the enzyme. This paper presents a study with purified lignin samples to elucidate the role of unproductive enzyme adsorption. It appeared that lignin adsorbed cellulase quickly at 4 °C with adsorption equilibrium reached within 1h, similar to that observed for crystalline cellulose. Increasing temperature to 50 °C (typical hydrolytic reaction condition) facilitated the rate of cellulase adsorption on cellulose with a peak of adsorption reached at 0.25 h; however, adsorption on lignin was surprisingly slower and took over 12h to reach equilibrium, which was accompanied with a 10-fold increase in adsorption capacity. Despite the high adsorption capacity of lignin (which is comparable to that of cellulose) at 50 °C, the presence of added lignin imposed only minimal impact on the enzyme apparent activity, most likely due to the slow adsorption kinetics of lignin.

  4. Correlation between lignin physicochemical properties and inhibition to enzymatic hydrolysis of cellulose.

    PubMed

    Yang, Qiang; Pan, Xuejun

    2016-06-01

    Using isolated organosolv lignins from hardwood poplar and softwood lodgepole pine with varied physicochemical properties (molecular weight, aliphatic hydroxyl, phenolic hydroxyl, and hydrophobicity), the inhibitory effect of the lignins on enzymatic hydrolysis of cellulose was investigated and the relationship between lignin properties and the inhibitory effect was elucidated. The results indicated that the lignin inhibition to enzymatic hydrolysis of cellulose was closely related to the hydrophobicity and the phenolic hydroxyl groups of the lignin. The overall hydrophobicity of the lignin quantified by contact angle could serve as a predictor of the inhibitory effect of lignin. Hydrophilic modification of the lignin by carboxylation and sulfonation reduced the hydrophobicity by 22-30% and thereby removed the lignin inhibition by 76-96%. Phenolic hydroxyl group was a crucial factor affecting the inhibitory effect of lignin. Blocking free phenolic hydroxyl group by chemical reaction such as hydroxypropylation significantly (65-91%) reduced the inhibitory effect of lignin. Biotechnol. Bioeng. 2016;113: 1213-1224. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  5. Efficient sugar release by the cellulose solvent-based lignocellulose fractionation technology and enzymatic cellulose hydrolysis.

    PubMed

    Moxley, Geoffrey; Zhu, Zhiguang; Zhang, Y-H Percival

    2008-09-10

    Efficient liberation of fermentable soluble sugars from lignocellulosic biomass waste not only decreases solid waste handling but also produces value-added biofuels and biobased products. Industrial hemp, a special economic crop, is cultivated for its high-quality fibers and high-value seed oil, but its hollow stalk cords (hurds) are a cellulosic waste. The cellulose-solvent-based lignocellulose fractionation (CSLF) technology has been developed to separate lignocellulose components under modest reaction conditions (Zhang, Y.-H. P.; Ding, S.-Y.; Mielenz, J. R.; Elander, R.; Laser, M.; Himmel, M.; McMillan, J. D.; Lynd, L. R. Biotechnol. Bioeng. 2007, 97 (2), 214- 223). Three pretreatment conditions (acid concentration, reaction temperature, and reaction time) were investigated to treat industrial hemp hurds for a maximal sugar release: a combinatorial result of a maximal retention of solid cellulose and a maximal enzymatic cellulose hydrolysis. At the best treatment condition (84.0% H3PO4 at 50 degrees C for 60 min), the glucan digestibility was 96% at hour 24 at a cellulase loading of 15 filter paper units of cellulase per gram of glucan. The scanning electron microscopic images were presented for the CSLF-pretreated biomass for the first time, suggesting that CSLF can completely destruct the plant cell-wall structure, in a good agreement with the highest enzymatic cellulose digestibility and fastest hydrolysis rate. It was found that phosphoric acid only above a critical concentration (83%) with a sufficient reaction time can efficiently disrupt recalcitrant lignocellulose structures.

  6. Fractionation of enzymatic hydrolysis lignin by sequential extraction for enhancing antioxidant performance.

    PubMed

    An, Liangliang; Wang, Guanhua; Jia, Hongyu; Liu, Cuiyun; Sui, Wenjie; Si, Chuanling

    2017-03-07

    The heterogeneity of lignin chemical structure and molecular weight results in the lignin inhomogeneous properties which also covers the antioxidant performance. In order to evaluate the effects of lignin heterogeneity on its antioxidant activity, four lignin fractions from enzymatic hydrolysis lignin were classified by sequential organic solvent extraction and further evaluated by DPPH (1,1-Diphenyl-2-Picrylhydrazyl) free radical scavenging capacity and reducing power analysis. The characterization including FTIR, (1)H NMR and GPC showed that the fractionation process could effectively separate lignin fractions with distinctly different molecular weight and weaken the heterogeneity of unfractionated lignin. The antioxidant performance comparison of lignin fractions indicated that the dichloromethane fraction (F1) with lowest molecular weight (4585g/mol) and highest total phenolics content (246.13mg GAE/g) exhibited the highest antioxidant activity whose value was close to commercial antioxidant BHT (butylated hydroxytoluene). Moreover, the relationship between the antioxidant activity and the structure of lignin was further discussed to elucidate the mechanism of antioxidant activity improvement of lignin fractionation. Consequently, this study suggested that the sequential extraction was an effective way to obtain relatively homogeneous enzymatic hydrolysis lignin fractions which showed the potential for the value-added antioxidant application.

  7. Response surface optimization of enzymatic hydrolysis of duck blood corpuscle using commercial proteases.

    PubMed

    Zheng, Zhaojun; Huang, Yan; Wu, Rujuan; Zhao, Longmei; Wang, Chunfeng; Zhang, Rijun

    2014-10-01

    With the rapid development in livestock and poultry husbandry and increasing shortage of protein sources, recycling of wastes from agricultural and food processing such as blood corpuscles has been regarded as an important industrial procedure to obtain protein sources. This study aimed to find an appropriate method for recycling the considerable amounts of blood corpuscle so as to improve its nutritional value and organoleptic quality. An effective production process for enzymatic hydrolysis of duck blood corpuscle was successfully developed and optimized by response surface methodology. Optimal conditions based on achieving a high value of trichloroacetic acid solubility index were substrate concentration of 14 g/100 mL, temperature 51°C, initial pH 7.0, and time 7.5 h. The electrophoretic patterns of the protein hydrolysate were investigated, and a large diffuse band was observed in the vicinity of 5 kDa. The organoleptic quality of spray-dried blood corpuscle hydrolysate was also evaluated, indicating that enzymatic hydrolysis and decoloration methods were feasible and cost-effective to achieve the desirable bright yellow product without bitterness. In vitro protein digestibility of blood corpuscle hydrolysate was 96.32 ± 0.50%, which was better than that of soybean, fish meal, and casein. Based on the amino acid composition and nutritional parameters, we found that the spray-dried blood corpuscle hydrolysate had abundant nutritional value and high potential for application as an ingredient in nonruminant animal feed. ©2014 Poultry Science Association Inc.

  8. Production of fermentable sugars from sugarcane bagasse by enzymatic hydrolysis after autohydrolysis and mechanical refining.

    PubMed

    Batalha, Larisse Aparecida Ribas; Han, Qiang; Jameel, Hasan; Chang, Hou-Min; Colodette, Jorge Luiz; Borges Gomes, Fernando José

    2015-03-01

    The autohydrolysis process has been considered a simple, low-cost and environmental friendly technology for generation of sugars from biomass. In order to improve accessibility of enzymes during enzymatic hydrolysis as well as to allow the recovery of hemicellulose in the filtrate, the sugarcane bagasse was pretreated using autohydrolysis followed by a mechanical refining process. The autohydrolysis was carried out in three different conditions. Autohydrolysis at 190°C for 10min provided the highest overall sugar (19.2/100g raw bagasse) in prehydrolyzate. The enzymatic hydrolysis step was performed for all the post-treated solids with and without refining at enzyme loadings of 5 and 10FPU/g for 96h. A total of 84.4% of sugar can be recovered from sugarcane bagasse at 180°C for 20min with 5 FPU/g enzyme charge. The economic analysis for the proposed method showed that the bioethanol production can have a financial return larger than 12%.

  9. Enzymatic hydrolysis of beer brewers' spent grain and the influence of pretreatments

    SciTech Connect

    Beldman, G.; Hennekam, J.; Voragen, A.G.J.

    1987-01-01

    The enzymatic saccharification of plant material has been shown to be of interest in various fields, such as the production of fruit juices and the utilization of biomass. A combination of cellulase, pectinase, and hemicellulases is usually used because of the chemical composition of the matrix of plant cell walls. For apples, beet pulp, and potato fiber, almost a complete hydrolysis of polysaccharides is obtained by combining cellulase and pectinase. For nonparenchymatic tissue, the situation is somewhat different: pectin is a minor component and the hemicellulose content is much higher. Enzyme action is restricted by the lignin barrier and by the high crystallinity of cellulose in this material. For such materials, mechanical, thermal, or chemical pretreatments are necessary to achieve efficient hydrolysis. This communication describes various enzymatic treatments and chemical and physical pretreatment, using brewers' spent grain as substrate. Spent grain is the residue of malt and grain which remains in the mash-kettle after the liquefied and saccharified starch has been removed by filtration. (Refs. 15).

  10. Enzymatic hydrolysis of beer brewers' spent grain and the influence of pretreatments.

    PubMed

    Beldman, G; Hennekam, J; Voragen, A G

    1987-10-05

    The enzymatic saccharification of plant material has been shown to be of interest in various fields, such as the production of fruit juices(1,2) and the utilization of biomass.(3) A combination of cellulase, pectinase, and hemicellulases is usually used because of the chemical composition of the matrix of plant cell walls.For apples, beet pulp, and potato fiber, almost a complete hydrolysis of polysaccharides is obtained by combining cellulose and pectinase. For nonparenchymatic tissue, the situation is somewhat different: pectin is a minor component and the hemicellulose content is much higher. Enzyme action is restricted by the lignin barrier and by the high crystallianity of cellulose in this material. For such materials, mechanical, thermal, or chemical pretreatments are necessary to achieve hydrolysis.(4,5)This communication describes various enzymatic treatements and chemical and physical pretreatemtn, using brewers' spent grain as substrate. Spent grain is the residue of malt and grain which remains in the mash-kettle after the liquefied and saccharified starch has been removed by filtration.

  11. Extraction and characterization of wax from sugarcane bagasse and the enzymatic hydrolysis of dewaxed sugarcane bagasse.

    PubMed

    Qi, Gaoxiang; Peng, Fen; Xiong, Lian; Lin, Xiaoqing; Huang, Chao; Li, Hailong; Chen, Xuefang; Chen, Xinde

    2017-03-16

    Extraction of high-value products from agricultural wastes is an important component for sustainable bioeconomy development. In this study, wax extraction from sugarcane bagasse was performed and the beneficial effect of dewaxing pretreatment on the enzymatic hydrolysis was investigated. About 1.2% (w/w) of crude sugarcane wax was obtained from the sugarcane bagasse using the mixture of petroleum ether and ethanol (mass ratio of 1:1) as the extraction agent. Results of Fourier-transform infrared characterization and gas chromatography-mass spectrometry qualitative analysis showed that the crude sugarcane wax consisted of fatty fractions (fatty acids, fatty aldehydes, hydrocarbons, and esters) and small amount of lignin derivatives. In addition, the effect of dewaxing pretreatment on the enzymatic hydrolysis of sugarcane bagasse was also investigated. The digestibilities of cellulose and xylan in dewaxed sugarcane bagasse were 18.7 and 10.3%, respectively, compared with those of 13.1 and 8.9% obtained from native sugarcane bagasse. The dewaxed sugarcane bagasse became more accessible to enzyme due to the disruption of the outermost layer of the waxy materials.

  12. Immobilization of trypsin in organic and aqueous media for enzymatic peptide synthesis and hydrolysis reactions.

    PubMed

    Stolarow, Julia; Heinzelmann, Manuel; Yeremchuk, Wladimir; Syldatk, Christoph; Hausmann, Rudolf

    2015-08-19

    Immobilization of enzymes onto different carriers increases enzyme's stability and reusability within biotechnological and pharmaceutical applications. However, some immobilization techniques are associated with loss of enzymatic specificity and/or activity. Possible reasons for this loss are mass transport limitations or structural changes. For this reason an immobilization method must be selected depending on immobilisate's demands. In this work different immobilization media were compared towards the synthetic and hydrolytic activities of immobilized trypsin as model enzyme on magnetic micro-particles. Porcine trypsin immobilization was carried out in organic and aqueous media with magnetic microparticles. The immobilization conditions in organic solvent were optimized for a peptide synthesis reaction. The highest carrier activity was achieved at 1 % of water (v/v) in dioxane. The resulting immobilizate could be used over ten cycles with activity retention of 90 % in peptide synthesis reaction in 80 % (v/v) ethanol and in hydrolysis reaction with activity retention of 87 % in buffered aqueous solution. Further, the optimized method was applied in peptide synthesis and hydrolysis reactions in comparison to an aqueous immobilization method varying the protein input. The dioxane immobilization method showed a higher activity coupling yield by factor 2 in peptide synthesis with a maximum activity coupling yield of 19.2 % compared to aqueous immobilization. The hydrolysis activity coupling yield displayed a maximum value of 20.4 % in dioxane immobilization method while the aqueous method achieved a maximum value of 38.5 %. Comparing the specific activity yields of the tested immobilization methods revealed maximum values of 5.2 % and 100 % in peptide synthesis and 33.3 % and 87.5 % in hydrolysis reaction for the dioxane and aqueous method, respectively. By immobilizing trypsin in dioxane, a beneficial effect on the synthetic trypsin activity resilience

  13. Efficient ethanol production from dried oil palm trunk treated by hydrothermolysis and subsequent enzymatic hydrolysis.

    PubMed

    Eom, In-Yong; Yu, Ju-Hyun; Jung, Chan-Duck; Hong, Kyung-Sik

    2015-01-01

    Oil palm trunk (OPT) is a valuable bioresource for the biorefinery industry producing biofuels and biochemicals. It has the distinct feature of containing a large amount of starch, which, unlike cellulose, can be easily solubilized by water when heated and hydrolyzed to glucose by amylolytic enzymes without pretreatment for breaking down the biomass recalcitrance. Therefore, it is suggested as beneficial to extract most of the starch from OPT through autoclaving and subsequent amylolytic hydrolysis prior to pretreatment. However, this treatment requires high capital and operational costs, and there could be a high probability of microbial contamination during starch processing. In terms of biochemical conversion of OPT, this study aimed to develop a simple and efficient ethanol conversion process without any chemical use such as acids and bases or detoxification. For comparison with the proposed efficient ethanol conversion process, OPT was subjected to hydrothermal treatment at 180 °C for 30 min. After enzymatic hydrolysis of PWS, 43.5 g of glucose per 100 g dry biomass was obtained, which corresponds to 81.3 % of the theoretical glucose yield. Through subsequent alcohol fermentation, 81.4 % ethanol yield of the theoretical ethanol yield was achieved. To conduct the proposed new process, starch in OPT was converted to ethanol through enzymatic hydrolysis and subsequent fermentation prior to hydrothermal treatment, and the resulting slurry was subjected to identical processes that were applied to control. Consequently, a high-glucose yield of 96.3 % was achieved, and the resulting ethanol yield was 93.5 %. The proposed new process was a simple method for minimizing the loss of starch during biochemical conversion and maximizing ethanol production as well as fermentable sugars from OPT. In addition, this methodology offers the advantage of reducing operational and capital costs due to minimizing the process for ethanol production by excluding expensive

  14. The effect of natural antioxidants on haemoglobin-mediated lipid oxidation during enzymatic hydrolysis of cod protein.

    PubMed

    Halldorsdottir, Sigrun M; Kristinsson, Hordur G; Sveinsdottir, Holmfridur; Thorkelsson, Gudjon; Hamaguchi, Patricia Y

    2013-11-15

    Heating and changes in pH often practised during fish protein hydrolysis can cause lipid oxidation. The effect of natural antioxidants towards haemoglobin-mediated lipid oxidation during enzymatic hydrolysis of cod proteins was investigated. Different variants of a washed cod model system, containing different combinations of haemoglobin and natural antioxidants (l-ascorbic acid and Fuscus vesiculosus extract), were hydrolysed using Protease P "Amano" 6 at pH 8 and 36°C to achieve 20% degree of hydrolysis. Lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS) were analysed periodically during the hydrolysis process. The in vitro antioxidant activity of the final products was investigated. Results indicate that oxidation can develop rapidly during hydrolysis and antioxidant strategies are preferable to produce good quality products. Oxidation products did not have an impact on the in vitro antioxidant activity of the hydrolysates. The natural antioxidants inhibited oxidation during hydrolysis and contributed to the antioxidant activity of the final product.

  15. Feasibility of pressurization to speed up enzymatic hydrolysis of biological materials for multielement determinations.

    PubMed

    Moreda-Piñeiro, Antonio; Bermejo-Barrera, Adela; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Jorge; Alonso-Rodríguez, Elia; Muniategui-Lorenzo, Soledad; López-Mahía, Purificación; Prada-Rodríguez, Darío

    2007-03-01

    The feasibility of pressurized solvents (liquids at a high pressure and/or high temperature without the subcritical point being reached) has been newly investigated to accelerate enzymatic hydrolysis processes of mussel tissue for multielement determinations. The target elements (Al, As, Cd, Co, Cu, Fe, Hg, Li, Mn, Pb, Se, Sr, V, and Zn) were released from dried mussel tissue by action of two proteases (pepsin and pancreatin), and they have been evaluated by inductively coupled plasma optical emission spectrometry (ICP-OES). Variables inherent to the enzymatic activity (pH, ionic strength, temperature, and enzyme mass) and factors affecting pressurization (static time, pressure, and number of cycles) were simultaneously studied by applying a Plackett-Burman design (PBD) as the screening method. Results showed that pH, ionic strength, and temperature were the most statistically significant factors (confidence interval of 95%) under pressurized conditions for pepsin, while pH and ionic strength affected pancreatin activity. This means that metal extraction is mostly attributed to enzymatic activity. The static time (enzymatic hydrolysis time) was found statistically nonsignificant for most of the elements, meaning that the hydrolysis procedure can be finished within a 2-15 min range. For pepsin, optimized conditions (pH 1.0, temperature 40 degrees C, pressure 1500 psi, static time 2 min, and number of cycles 3) gave quantitative extractions for As, Cd, Co, Cu, Hg, Li, Mn, Pb, Se, Sr, V, and Zn. The pepsin mass was 0.05 g, and the solution was Milli-Q water at pH 1.0 (adjusted with hydrochloric acid). For pancreatin, quantitative recoveries were only reached for As, Cd, Cu, Li, Pb, and Sr at room temperature, at a pressure of 1500 psi, for a static time of 2 min and a number of cycles of 3. The extraction solution was a 0.3 M potassium dihydrogen phosphate/potassium hydrogen phosphate buffer at a pH of 7.5 working at room temperature. Around 0.5 g of diatomaceous

  16. The enzymatic hydrolysis of pretreated pulp fibers predominantly involves “peeling/erosion” modes of action

    PubMed Central

    2014-01-01

    Background There is still considerable debate regarding the actual mechanism by which a “cellulase mixture” deconstructs cellulosic materials, with accessibility to the substrate at the microscopic level being one of the major restrictions that limits fast, complete cellulose hydrolysis. In the work reported here we tried to determine the predominant mode of action, at the fiber level, of how a cellulase mixture deconstructs pretreated softwood and hardwood pulp fibers. Quantitative changes in the pulp fibers derived from different pretreated biomass substrates were monitored throughout the course of enzymatic hydrolysis to see if the dominant mechanisms involved either the fragmentation/cutting of longer fibers to shorter fibers or their “peeling/delamination/erosion,” or if both cutting and peeling mechanisms occurred simultaneously. Results Regardless of the source of biomass, the type of pretreatment and the chemical composition of the substrate, under typical hydrolysis conditions (50°C, pH 4.8, mixing) longer pulp fibers (fiber length >200 μm) were rapidly broken down until a relatively constant fiber length of 130 to 160 μm was reached. In contrast, shorter fibers with an initial average fiber length of 130 to 160 μm showed no significant change in length despite their substantial hydrolysis. The fragmentation/cutting mode of deconstruction was only observed on longer fibers at early stages of hydrolysis. Although the fiber fragmentation mode of deconstruction was not greatly influenced by enzyme loading, it was significantly inhibited by glucose and was mainly observed during initial mixing of the enzyme and substrate. In contrast, significant changes in the fiber width occurred throughout the course of hydrolysis for all of the substrates, suggesting that fiber width may limit the rate and extent of cellulose hydrolysis. Conclusion It appears that, at the fiber level, pretreated pulp fibers are hydrolyzed through a two-step mode of action

  17. The enzymatic hydrolysis of pretreated pulp fibers predominantly involves "peeling/erosion" modes of action.

    PubMed

    Arantes, Valdeir; Gourlay, Keith; Saddler, Jack N

    2014-01-01

    There is still considerable debate regarding the actual mechanism by which a "cellulase mixture" deconstructs cellulosic materials, with accessibility to the substrate at the microscopic level being one of the major restrictions that limits fast, complete cellulose hydrolysis. In the work reported here we tried to determine the predominant mode of action, at the fiber level, of how a cellulase mixture deconstructs pretreated softwood and hardwood pulp fibers. Quantitative changes in the pulp fibers derived from different pretreated biomass substrates were monitored throughout the course of enzymatic hydrolysis to see if the dominant mechanisms involved either the fragmentation/cutting of longer fibers to shorter fibers or their "peeling/delamination/erosion," or if both cutting and peeling mechanisms occurred simultaneously. Regardless of the source of biomass, the type of pretreatment and the chemical composition of the substrate, under typical hydrolysis conditions (50°C, pH 4.8, mixing) longer pulp fibers (fiber length >200 μm) were rapidly broken down until a relatively constant fiber length of 130 to 160 μm was reached. In contrast, shorter fibers with an initial average fiber length of 130 to 160 μm showed no significant change in length despite their substantial hydrolysis. The fragmentation/cutting mode of deconstruction was only observed on longer fibers at early stages of hydrolysis. Although the fiber fragmentation mode of deconstruction was not greatly influenced by enzyme loading, it was significantly inhibited by glucose and was mainly observed during initial mixing of the enzyme and substrate. In contrast, significant changes in the fiber width occurred throughout the course of hydrolysis for all of the substrates, suggesting that fiber width may limit the rate and extent of cellulose hydrolysis. It appears that, at the fiber level, pretreated pulp fibers are hydrolyzed through a two-step mode of action involving an initial rapid

  18. Optimisation of the Enzymatic Hydrolysis of Blood Cells with a Neutral Protease

    PubMed Central

    Zheng, Yanbin; Chen, Qiushi; Shan, Anshan; Zhang, Hao

    2013-01-01

    For utilizing the blood cells (BCs) effectively, enzymatic hydrolysis was applied to produce the enzymatically hydrolyzed blood cells (EHBCs) by using a neutral protease as a catalyst. The results of the single-factor experiments showed optimal substrate concentration, enzyme to substrate ratio (E/S), pH, temperature, and incubation period were 1.00%, 0.10, 7.00, 50.00°C, and 12.00 h, respectively. The optimized hydrolysis conditions from response surface methodology (RSM) were pH 6.50, E/S 0.11, temperature 45.00°C, and incubation period 12.00 h. Under these conditions (substrate concentration 1.00%), the degree of hydrolysis (DH) was 35.06%. The free amino acids (FAAs) content of the EHBCs (35.24%) was 40.46 times higher than BCs while the total amino acids (TAAs) content was lower than BCs. The scores of lysine (human 0.87; pig 0.97), valine (human 1.42; pig 1.38), leucine (human 1.50; pig 1.90), tyrosine (human 0.84; pig 1.09), and histidine (human 2.17; pig 2.50) indicated that the EHBCs basically fulfilled the adult human and pig nutritional requirements. The calculated protein efficiency ratios (C-PERs) of the EHBCs were 3.94, 6.19, 21.73, and 2.04. In summary, the EHBCs were produced successfully with optimized conditions and could be a novel protein source for humans and pigs. PMID:23484101

  19. Ethanol production from cashew apple bagasse: improvement of enzymatic hydrolysis by microwave-assisted alkali pretreatment.

    PubMed

    Rodrigues, Tigressa Helena Soares; Rocha, Maria Valderez Ponte; de Macedo, Gorete Ribeiro; Gonçalves, Luciana R B

    2011-07-01

    In this work, the potential of microwave-assisted alkali pretreatment in order to improve the rupture of the recalcitrant structures of the cashew able bagasse (CAB), lignocellulosic by-product in Brazil with no commercial value, is obtained from cashew apple process to juice production, was studied. First, biomass composition of CAB was determined, and the percentage of glucan and lignin was 20.54 ± 0.70% and 33.80 ± 1.30%, respectively. CAB content in terms of cellulose, hemicelluloses, and lignin, 19.21 ± 0.35%, 12.05 ± 0.37%, and 38.11 ± 0.08%, respectively, was also determined. Results showed that, after enzymatic hydrolysis, alkali concentration exerted influence on glucose formation, after pretreatment with 0.2 and 1.0 mo L(-1) of NaOH (372 ± 12 and 355 ± 37 mg g(glucan)(-1) ) when 2% (w/v) of cashew apple bagasse pretreated by microwave-assisted alkali pretreatment (CAB-M) was used. On the other hand, pretreatment time (15-30 min) and microwave power (600-900 W) exerted no significant effect on hydrolysis. On enzymatic hydrolysis step, improvement on solid percentage (16% w/v) and enzyme load (30 FPU g (CAB-M) (-1) ) increased glucose concentration to 15 g L(-1). The fermentation of the hydrolyzate by Saccharomyces cerevesiae resulted in ethanol concentration and productivity of 5.6 g L(-1) and 1.41 g L(-1) h(-1), respectively.

  20. Optimisation of the enzymatic hydrolysis of blood cells with a neutral protease.

    PubMed

    Zheng, Yanbin; Chen, Qiushi; Shan, Anshan; Zhang, Hao

    2013-01-01

    For utilizing the blood cells (BCs) effectively, enzymatic hydrolysis was applied to produce the enzymatically hydrolyzed blood cells (EHBCs) by using a neutral protease as a catalyst. The results of the single-factor experiments showed optimal substrate concentration, enzyme to substrate ratio (E/S), pH, temperature, and incubation period were 1.00%, 0.10, 7.00, 50.00°C, and 12.00 h, respectively. The optimized hydrolysis conditions from response surface methodology (RSM) were pH 6.50, E/S 0.11, temperature 45.00°C, and incubation period 12.00 h. Under these conditions (substrate concentration 1.00%), the degree of hydrolysis (DH) was 35.06%. The free amino acids (FAAs) content of the EHBCs (35.24%) was 40.46 times higher than BCs while the total amino acids (TAAs) content was lower than BCs. The scores of lysine (human 0.87; pig 0.97), valine (human 1.42; pig 1.38), leucine (human 1.50; pig 1.90), tyrosine (human 0.84; pig 1.09), and histidine (human 2.17; pig 2.50) indicated that the EHBCs basically fulfilled the adult human and pig nutritional requirements. The calculated protein efficiency ratios (C-PERs) of the EHBCs were 3.94, 6.19, 21.73, and 2.04. In summary, the EHBCs were produced successfully with optimized conditions and could be a novel protein source for humans and pigs.

  1. Enzymatic cellulose hydrolysis: enzyme reusability and visualization of β-glucosidase immobilized in calcium alginate.

    PubMed

    Tsai, Chien-Tai; Meyer, Anne S

    2014-11-25

    The high cellulase enzyme dosages required for hydrolysis of cellulose is a major cost challenge in lignocellulosic ethanol production. One method to decrease the enzyme dosage and increase biocatalytic productivity is to re-use β-glucosidase (BG) via immobilization. In the present research, glutaraldehyde cross-linked BG was entrapped in calcium alginate gel particles. More than 60% of the enzyme activity could be recovered under optimized conditions, and glutaraldehyde cross-linking decreased leakage of BG from the calcium alginate particles. The immobilized BG aggregates were visualized by confocal laser scanning microscopy (CLSM). The CLSM images, which we believe are the first to be published, corroborate that more BG aggregates were entrapped in the matrix when the enzymes were cross-linked by glutaraldehyde as opposed to when they are not cross-linked. The particles with the immobilized BG were recycled for cellulase catalyzed hydrolysis of Avicel. No significant loss in BG activity was observed for up to 20 rounds of reaction recycle steps of the BG particles of 48 h each, verifying a significant stabilization of the BG by immobilization. Similar high glucose yields were obtained by one round of enzymatic hydrolysis of hydrothermally pretreated barley straw during a 72 h reaction with immobilized BG and free BG.

  2. Bioethanol Production By Utilizing Cassava Peels Waste Through Enzymatic And Microbiological Hydrolysis

    NASA Astrophysics Data System (ADS)

    Witantri, R. G.; Purwoko, T.; Sunarto; Mahajoeno, E.

    2017-07-01

    Cassava peels waste contains, cellulose which is quite high at 43.626%, this is a potential candidate as a raw for bioethanol production. The purpose of this study was to determine the performance of the enzymatic hydrolysis, microbiological (Effective microbe) and fermentation in cassava peel waste is known from the results of quantitative measurement of multiple ethanol parameters (DNS Test, pH, ethanol concentration). This research was carried out in stages, the first stage is hydrolysis with completely randomized design with single factor variation of the catalyst, consisting of three levels ie cellulase enzymes, multienzyme and effective microbial EM4. The second stage is fermentation with factorial randomized block design, consisting of three groups of variations of catalyst, and has two factors: variations of fermipan levels 1, 2, 3% and the duration of fermentation, 2,4,6 days. The parameters in the test is a reducing sugar, pH and concentration of ethanol. The results showed that variation of hydrolysis treatment, fermentation time, and fermipan levels has real effect on the fermentation process. On average the highest ethanol content obtained from the treatment with multienzyme addition, with the addition of 2% fermipan levels and on the 2nd day of fermentation that is equal to 3.76%.

  3. In situ rheometry of concentrated cellulose fibre suspensions and relationships with enzymatic hydrolysis.

    PubMed

    Nguyen, Tien-Cuong; Anne-Archard, Dominique; Coma, Véronique; Cameleyre, Xavier; Lombard, Eric; Binet, Cédric; Nouhen, Arthur; To, Kim Anh; Fillaudeau, Luc

    2013-04-01

    This work combines physical and biochemical analyses to scrutinize liquefaction and saccharification of complex lignocellulose materials. A multilevel analysis (macroscopic: rheology, microscopic: particle size and morphology and molecular: sugar product) was conducted at the lab-scale with three matrices: microcrystalline cellulose (MCC), Whatman paper (WP) and extruded paper-pulp (PP). A methodology to determine on-line viscosity is proposed and validated using the concept of Metzner and Otto (1957) and Rieger and Novak's (1973). The substrate suspensions exhibited a shear-thinning behaviour with respect to the power law. A structured rheological model was established to account for the suspension viscosity as a function of shear rate and substrate concentration. The critical volume fractions indicate the transition between diluted, semi-diluted and concentrated regimes. The enzymatic hydrolysis was performed with various solid contents: MCC 273.6 gdm/L, WP 56.0 gdm/L, PP 35.1 gdm/L. During hydrolysis, the suspension viscosity decreased rapidly. The fibre diameter decreased two fold within 2 h of starting hydrolysis whereas limited bioconversion was obtained (10-15%).

  4. Enhanced enzymatic hydrolysis and ethanol production from cashew apple bagasse pretreated with alkaline hydrogen peroxide.

    PubMed

    da Costa, Jessyca Aline; Marques, José Edvan; Gonçalves, Luciana Rocha Barros; Rocha, Maria Valderez Ponte

    2015-03-01

    The effect of combinations and ratios between different enzymes has been investigated in order to assess the optimal conditions for hydrolysis of cashew apple bagasse pretreated with alkaline hydrogen peroxide (the solids named CAB-AHP). The separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) processes were evaluated in the ethanol production. The enzymatic hydrolysis conducted with cellulase complex and β-glucosidase in a ratio of 0.61:0.39, enzyme loading of 30FPU/g(CAB-AHP) and 66CBU/g(CAB-AHP), respectively, using 4% cellulose from CAB-AHP, turned out to be the most effective conditions, with glucose and xylose yields of 511.68 mg/g(CAB-AHP) and 237.8 mg/g(CAB-AHP), respectively. Fermentation of the pure hydrolysate by Kluyveromyces marxianus ATCC 36907 led to an ethanol yield of 61.8kg/ton(CAB), corresponding to 15 g/L ethanol and productivity of 3.75 g/( Lh). The ethanol production obtained for SSF process using K. marxianus ATCC 36907 was 18 g/L corresponding to 80% yield and 74.2kg/ton(CAB).

  5. Effect of bisulfite treatment on composition, structure, enzymatic hydrolysis and cellulase adsorption profiles of sugarcane bagasse.

    PubMed

    Liu, Z J; Lan, T Q; Li, H; Gao, X; Zhang, H

    2017-01-01

    The effect of sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) on composition, structure, enzymatic hydrolysis and cellulase adsorption profiles of sugarcane bagasse (SCB) was investigated. SPORL gave a higher SCB hydrolysis yield (85.33%) compared to dilute acid pretreatment (DA) (64.39%). The SEM pictures showed that SPORL SCB structure became more disordered and looser, suggesting SPORL SCB was more accessible to cellulase. The zeta potential of SPORL SCB suspension (-21.89mV) was significantly different from that of DA SCB (-12.87mV), which demonstrated the lignin in SPORL SCB was more hydrophilic. With regard to cellulase adsorption profiles, SPORL SCB had a lower non-productive adsorption (14.87mg/glignin) and a higher productive adsorption (37.67 mg/gcarbohydrate) compared with DA SCB (17.05mg/glignin; 25.79mg/gcarbohydrate). These results indicated that SPORL SCB had better accessibility to cellulase and the higher productive cellulase adsorption of SPORL SCB had improved hydrolysis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Effect of cross-linking and enzymatic hydrolysis composite modification on the properties of rice starches.

    PubMed

    Xiao, Huaxi; Lin, Qinlu; Liu, Gao-Qiang

    2012-07-06

    Native rice starch lacks the versatility necessary to function adequately under rigorous industrial processing, so modified starches are needed to meet the functional properties required in food products. This work investigated the impact of enzymatic hydrolysis and cross-linking composite modification on the properties of rice starches. Rice starch was cross-linked with epichlorohydrin (EPI) with different concentrations (0.5%, 0.7%, 0.9% w/w, on a dry starch basis), affording cross-linked rice starches with the three different levels of cross-linking that were named R₁, R₂, and R₃, respectively. The cross-linked rice starches were hydrolyzed by α-amylase and native, hydrolyzed, and hydrolyzed cross-linked rice starches were comparatively studied. It was found that hydrolyzed cross-linked rice starches showed a lower the degree of amylase hydrolysis compared with hydrolyzed rice starch. The higher the degree of cross-linking, the higher the capacity to resist enzyme hydrolysis. Hydrolyzed cross-linked rice starches further increased the adsorptive capacities of starches for liquids and decreased the trend of retrogradation, and it also strengthened the capacity to resist shear compared to native and hydrolyzed rice starches.

  7. Step enzymatic hydrolysis of sodium hydroxide-pretreated Chinese liquor distillers' grains for ethanol production.

    PubMed

    Liu, Yue-Hong; Wu, Zheng-Yun; Yang, Jian; Yuan, Yu-Ju; Zhang, Wen-Xue

    2014-01-01

    Distillers' grains are a co-product of ethanol production. In China, only a small portion of distillers' grains have been used to feed the livestock because the amount was so huge. Nowadays, it has been reported that the distillers' grains have the potential for fuel ethanol production because they are composed of lignocelluloses and residual starch. In order to effectively convert distillers' grains to fuel ethanol and other valuable production, sodium hydroxide pretreatment, step-by-step enzymatic hydrolysis, and simultaneous saccharification and fermentation (SSF) were investigated. The residual starch was first recycled from wet distillers' grains (WDG) with glucoamylase to obtain glucose-rich liquid. The total sugar concentration was 21.3 g/L, and 111.9% theoretical starch was hydrolyzed. Then the removed-starch dry distillers' grains (RDDG) were pretreated with NaOH under optimal conditions and the pretreated dry distillers' grains (PDDG) were used for xylanase hydrolysis. The xylose concentration was 19.4 g/L and 68.6% theoretical xylose was hydrolyzed. The cellulose-enriched dry distillers' grains (CDDG) obtained from xylanase hydrolysis were used in SSF for ethanol production. The ethanol concentration was 42.1 g/L and the ethanol productivity was 28.7 g/100 g CDDG. After the experiment, approximately 80.6% of the fermentable sugars in WDG was converted to ethanol.

  8. [Study of the enzymatic hydrolysis of a phosphonic ester using microcalorimetry].

    PubMed

    Labadie, M; Debord, J; Breton, J C

    1979-01-01

    A "Batch" microcalorimeter is used at 30 degrees C for the study of the hydrolysis of 4-nitro-phenylphenylphosphonate with a calf-intestinal phosphonate esterase, in a tris buffer, pH 8. The yield of enzymatic hydrolysis is estimated by spectrophotometric determination of the p--nitrophenol evolved; we have then calculated the apparent molar enthalph of the reaction. (delta Happ = -72,2 kj. mol-1). Phenylphosphonic acid, the second reaction product, is not transphosphonylated on tris. The second acidity of phenylphosphonic acid was studied at 30 degrees C by sodium hydroxide electrotitration (pKa2 = 7,13) and by "Flow" microcalorimetry (delta Hionization = 19,8 kj.mol-1). In the same manner at 30 degrees C, we measured the heat of ionization of p-nitrophenol (delta Hionization = 26,75 kj.mol-1). These findings allow a calculation for the actual heat of hydrolysis of 4-nitro-phenyl-phenylphosphonate (delta Hrho = -29,7 kj.mol-1).

  9. Enhanced the enzymatic hydrolysis efficiency of wheat straw after combined steam explosion and laccase pretreatment.

    PubMed

    Qiu, Weihua; Chen, Hongzhang

    2012-08-01

    Laccase, capable of selectively degrading lignin while keeping cellulose intact, has been widely applied for the modification and bio-bleaching of pulp. In this study Sclerotium sp. laccase (MSLac) was employed in combination with steam explosion to evaluate the effect of this treatment on cellulose hydrolysis. Combined steam explosion with laccase pretreatment enhanced the cellulose conversion rate of wheat straw no matter in the case of successive (MSLac-Cel) and simultaneous (MSLac+Cel) MSLac and cellulase hydrolysis. The highest cellulose conversion rate of 84.23% was obtained when steam-exploded wheat straw (SEWS) (1.3 MPa, 5 min) was treated by MSLac+Cel at a laccase loading of 0.55 U g(-1) substrate. FT-IR and SEM analyses indicated that MSLac oxidized the phenol and changed electron configuration of the ring, which contributed to loosening the compact wrap of lignin-carbohydrate complex and consequently enhancing the enzymatic hydrolysis efficiency of cellulose. This article provided a promising method for lignocellulose bio-pretreatment.

  10. Continuous synthesis of lactulose in an enzymatic membrane reactor reduces lactulose secondary hydrolysis.

    PubMed

    Sitanggang, Azis Boing; Drews, Anja; Kraume, Matthias

    2014-09-01

    Newly developed parallel small-scale enzymatic membrane reactors (EMRs) were used to enhance the synthesis of lactulose using β-galactosidase. Under batch operation, the productivity of lactulose decreased abruptly from 2.72 down to 0.04 mg lactulose/(Uenzymeh) over 35 h of reaction. This was presumably caused by the action of β-galactosidase which performed secondary hydrolysis upon the produced lactulose. The continuous operations of an EMR system led to continuous removal of lactulose in the reactors restricting lactulose degradation caused by secondary hydrolysis. Therefore, continuous lactulose syntheses in the EMRs yielded significantly higher specific productivities under "steady state" conditions. Approximately 0.70 and 0.50 mg lactulose/(U enzyme h) for hydraulic residence times of 5 and 7h were reached, respectively. Continuous lactulose synthesis performed in an EMR system conclusively can circumvent the drawbacks (e.g., secondary hydrolysis) of lactulose synthesis encountered in batch operation. It is, therefore, beneficial in terms of enhanced lactulose productivity and reduced enzyme consumption. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Effects of enzymatic hydrolysis and ultrasounds pretreatments on corn cob and vine trimming shoots for biogas production.

    PubMed

    Pérez-Rodríguez, N; García-Bernet, D; Domínguez, J M

    2016-12-01

    Due to their lignocellulosic nature, corn cob and vine trimming shoots (VTS) could be valorized by anaerobic digestion for biogas production. To enhance the digestibility of substrates, pretreatments of lignocellulosic materials are recommended. The effect of enzymatic hydrolysis, ultrasounds pretreatments (US) and the combination of both was assayed in lignocellulosic composition, methane, and biogas yields. The pretreatments leaded to a reduction in lignin and an increase in neutral detergent soluble compounds making corn cob and VTS more amendable for biogas conversion. The US were negative for biogas production from both substrates and in particular strongly detrimental for VTS. On the opposite side, the enzymatic hydrolysis was certainly beneficial increasing 59.8% and 14.6% the methane production from VTS and corn cob, respectively. The prior application of US did not potentiate (or not sufficiently) the improvement in the methane production reflected by the enzymatic hydrolysis pretreatment of VTS and corn cob. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Comparison of sodium hydroxide and calcium hydroxide pretreatments on the enzymatic hydrolysis and lignin recovery of sugarcane bagasse.

    PubMed

    Chang, Menglei; Li, Denian; Wang, Wen; Chen, Dongchu; Zhang, Yuyuan; Hu, Huawen; Ye, Xiufang

    2017-08-19

    Sodium hydroxide (NaOH) and calcium hydroxide (Ca(OH)2) respectively dissolved in water and 70% glycerol were applied to treat sugarcane bagasse (SCB) under the condition of 80°C for 2h. NaOH solutions could remove more lignin and obtain higher enzymatic hydrolysis efficiency of SCB than Ca(OH)2 solutions. Compared with the alkali-water solutions, the enzymatic hydrolysis of SCB treated in NaOH-glycerol solution decreased, while that in Ca(OH)2-glycerol solution increased. The lignin in NaOH-water pretreatment liquor could be easily recovered by calcium chloride (CaCl2) at room temperature, but that in Ca(OH)2-water pretreatment liquor couldn't. NaOH pretreatment is more suitable for facilitating enzymatic hydrolysis and lignin recovery of SCB than Ca(OH)2 pretreatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Improvement of enzymatic hydrolysis and ethanol production from corn stalk by alkali and N-methylmorpholine-N-oxide pretreatments.

    PubMed

    Cai, Ling-Yan; Ma, Yu-Long; Ma, Xiao-Xia; Lv, Jun-Min

    2016-07-01

    A combinative technology of alkali and N-methylmorpholine-N-oxide (NMMO) was used to pretreat corn stalk (CS) for improving the efficiencies of subsequent enzymatic hydrolysis and ethanol fermentation. The results showed that this strategy could not only remove hemicellulose and lignin but also decrease the crystallinity of cellulose. About 98.0% of enzymatic hydrolysis yield was obtained from the pretreated CS as compared with 46.9% from the untreated sample. The yield for corresponding ethanol yield was 64.6% while untreated CS was only 18.8%. Besides, xylose yield obtained from the untreated CS was only 11.1%, while this value was 93.8% for alkali with NMMO pretreated sample. These results suggest that a combination of alkali with 50% (wt/wt) NMMO solution may be a promising alternative for pretreatment of lignocellulose, which can increase the productions of subsequent enzymatic hydrolysis and ethanol fermentation.

  14. Enhanced enzymatic hydrolysis of eucalyptus by synergy of zinc chloride hydrate pretreatment and bovine serum albumin.

    PubMed

    Wei, Weiqi; Wu, Shubin

    2017-08-24

    Enhancement of eucalyptus enzymatic saccharification by synergy of ZnCl2 hydrate pretreatment and bovine serum albumin (BSA) was investigated in this study. The result showed that the ZnCl2 hydrate pretreatment could not only selectively extract up to ∼100% of the hemicellulose from eucalyptus, but also convert portion of high crystalline cellulose I into low crystalline cellulose II, which both beneficial for enhancing subsequent pretreated solids enzymatic saccharification. The addition of BSA into enzymatic hydrolysis step could significantly promote the glucose release from pretreated solids, especially, under the low enzyme loading. Furthermore, the material balance indicated that the highest glucose yield of this study was 35.5g/100g raw material, which representing 90.3% of glucose in raw eucalyptus, combined with the xylose yield, 13.9g/100g eucalyptus, it can be concluded that ZnCl2 hydrate pretreatment offered the potential to co-produce xylose and glucose from eucalyptus. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Cellulolytic enzyme production and enzymatic hydrolysis for second-generation bioethanol production.

    PubMed

    Wang, Mingyu; Li, Zhonghai; Fang, Xu; Wang, Lushan; Qu, Yinbo

    2012-01-01

    Second-generation bioethanol made from lignocellulosic biomass is considered one of the most promising biofuels. However, the enzymatic hydrolysis of the cellulose component to liberate glucose for ethanol fermentation is one of the major barriers for the process to be economically competitive because of the recalcitrance of feedstock. In this chapter, the progress on the understanding of the mechanisms of lignocellulose degradation, as well as the identification and optimization of fungal cellulases, cellulolytic strains, and cellulase production is reviewed. The physiologic functions and enzymatic mechanisms of two groups of enzymes involved in lignocellulose degradation, cellulases and hemicellulases, are discussed, and the synergism of the cellulase components during lignocellulose degradation is addressed. Furthermore, the methods for screening filamentous fungal strains capable of degrading lignocellulose are evaluated and the production of cellulases by these fungal strains is discussed. Aside from traditional mutagenesis for improving the secretion level and enzymatic activities of cellulases from filamentous fungal species, genetic engineering of strains and protein engineering on cellulase molecules are also highlighted.

  16. Improving enzymatic hydrolysis of corn stover pretreated by ethylene glycol-perchloric acid-water mixture.

    PubMed

    He, Yu-Cai; Liu, Feng; Gong, Lei; Lu, Ting; Ding, Yun; Zhang, Dan-Ping; Qing, Qing; Zhang, Yue

    2015-02-01

    To improve the enzymatic saccharification of lignocellulosic biomass, a mixture of ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) was used for pretreating corn stover in this study. After the optimization in oil-bath system, the optimum pretreatment temperature and time were 130 °C and 30 min, respectively. After the saccharification of 10 g/L pretreated corn stover for 48 h, the saccharification rate was obtained in the yield of 77.4 %. To decrease pretreatment temperature and shorten pretreatment time, ethylene glycol-HClO4-water (88.8:1.2:10, w/w/w) media under microwave irradiation was employed to pretreat corn stover effectively at 100 °C and 200 W for 5 min. Finally, the recovered hydrolyzates containing glucose obtained from the enzymatic hydrolysis of pretreated corn stovers could be fermented into ethanol efficiently. These results would be helpful for developing a cost-effective pretreatment combined with enzymatic saccharification of cellulosic materials for the production of lignocellulosic ethanol.

  17. Phenols and lignin: Key players in reducing enzymatic hydrolysis yields of steam-pretreated biomass in presence of laccase.

    PubMed

    Oliva-Taravilla, Alfredo; Tomás-Pejó, Elia; Demuez, Marie; González-Fernández, Cristina; Ballesteros, Mercedes

    2016-01-20

    Phenols are known as inhibitors for cellulases and fermentative microorganisms in bioethanol production processes. The addition of laccases removes the phenolic compounds and subsequently reduces the lag phase of the fermentative microorganism. However, the application of laccases diminishes glucose release during the enzymatic hydrolysis. In this study a model cellulosic substrate (Sigmacell) together with lignin extract, whole steam-pretreated wheat straw (slurry) and its water insoluble solid fraction (WIS) were subjected to enzymatic hydrolysis to evaluate the effects of laccase treatment in presence of lignin and phenols. The presence of laccase in enzymatic hydrolysis of Sigmacell with lignin extract reduced glucose yield by 37% compared with assays without laccase. Furthermore, this reduction was even more marked in presence of phenols (55% reduction). Interestingly, when hydrolyzing WIS, the addition of phenols coupled with laccase treatment did not show a reduction when compared with only laccase addition. This fact suggests the key role of lignin in the hydrolysis inhibition since in WIS the ratio cellulase per gram of lignin was much lower than in Sigmacell experiments. Finally, the lower cellobiose and xylose recoveries point out that phenolic oligomers formed by laccase oxidation play important roles in the inhibition of endoglucanases, cellobiohydrolases and xylanases. To conclude, the proportion of lignin and the composition of phenols are key players in the inhibition of cellulases when the enzymatic hydrolysis is combined with laccases detoxification.

  18. Incomplete hydrolysis of cholesteryl esters during the enzymatic cholesterol determination as evidenced by aqueous cholesteryl ester solutions: comparison of six enzymatic procedures with the Liebermann-Burchard method.

    PubMed

    Tel, R M; Berends, G T

    1980-10-01

    Aqueous solutions of cholesterol and some cholesteryl esters were prepared. The hydrolysis of cholesteryl esters with enzymatic methods could therefore be studied in some detail. The total cholesterol concentration of the aqueous cholesterol and cholesteryl ester solutions was determined by 6 different enzymatic procedures as well as the Liebermann-Burchard method. For some esters (acetate and arachidonate esters) the esterase reaction is not complete within the usual reaction time, whereas most other esters gave analytical results lower than the theoretical. With the Liebermann-Burchard method all esters reacted completely within the reaction time. The esterase have very different specificities for the various cholesteryl esters. With the enzymatic method several commercial control sera as well as human sera gave lower cholesterol concentrations than the Liebermann-Burchard method. These differences can be explained mainly by this incomplete hydrolysis. Some practical recommendations are given.

  19. Enzymatic hydrolysis of heated whey: iron-binding ability of peptides and antigenic protein fractions.

    PubMed

    Kim, S B; Seo, I S; Khan, M A; Ki, K S; Lee, W S; Lee, H J; Shin, H S; Kim, H S

    2007-09-01

    This study evaluated the influence of various enzymes on the hydrolysis of whey protein concentrate (WPC) to reduce its antigenic fractions and to quantify the peptides having iron-binding ability in its hydrolysates. Heated (for 10 min at 100 degrees C) WPC (2% protein solution) was incubated with 2% each of Alcalase, Flavourzyme, papain, and trypsin for 30, 60, 90, 120, 150, 180, and 240 min at 50 degrees C. The highest hydrolysis of WPC was observed after 240 min of incubation with Alcalase (12.4%), followed by Flavourzyme (12.0%), trypsin (10.4%), and papain (8.53%). The nonprotein nitrogen contents of WPC hydrolysate followed the hydrolytic pattern of whey. The major antigenic fractions (beta-lactoglobulin) in WPC were degraded within 60 min of its incubation with Alcalase, Flavourzyme, or papain. Chromatograms of enzymatic hydrolysates of heated WPC also indicated complete degradation of beta-lactoglobulin, alpha-lactalbumin, and BSA. The highest iron solubility was noticed in hydrolysates derived with Alcalase (95%), followed by those produced with trypsin (90%), papain (87%), and Flavourzyme (81%). Eluted fraction 1 (F-1) and fraction 2 (F-2) were the respective peaks for the 0.25 and 0.5 M NaCl chromatographic step gradient for analysis of hydrolysates. Iron-binding ability was noticeably higher in F-1 than in F-2 of all hydrolysates of WPC. The highest iron contents in F-1 were observed in WPC hydrolysates derived with Alcalase (0.2 mg/kg), followed by hydrolysates derived with Flavourzyme (0.14 mg/kg), trypsin (0.14 mg/kg), and papain (0.08 mg/kg). Iron concentrations in the F-2 fraction of all enzymatic hydrolysates of WPC were low and ranged from 0.03 to 0.05 mg/kg. Fraction 1 may describe a new class of iron chelates based on the reaction of FeSO4 x 7 H2O with a mixture of peptides obtained by the enzymatic hydrolysis of WPC. The chromatogram of Alcalase F-1 indicated numerous small peaks of shorter wavelengths, which probably indicated a variety of

  20. Optimization of covalent immobilization of Trichoderma reesei cellulase onto modified ReliZyme HA403 and Sepabeads EC-EP supports for cellulose hydrolysis, in buffer and ionic liquids/buffer media.

    PubMed

    Bilgin, Ramazan; Yalcin, M Serkan; Yildirim, Deniz

    2016-08-01

    The covalent immobilization of Trichoderma reesei cellulase onto modified ReliZyme HA403 and Sepabeads EC-EP supports were carried out. The optimal immobilization conditions were determined using response surface methodology. The hydrolysis of cellulose using the free and immobilized cellulase preparations in ionic liquids (IL) using cosolvents was investigated. The hydrolytic activities in buffer medium containing 25% (v/v) of 1-butyl-3-methylimidazolium hexafluorophosphate were around 2.6-, 1.6-, and 5.5-fold higher than the activities in buffer medium. The retained initial activities were 32% and 57%, respectively for cellulase preparations immobilized onto Sepabeads EC-EP support and onto modified ReliZyme HA403 support after 5 reuses.

  1. Mechanism of the discrepancy in the enzymatic hydrolysis efficiency between defatted peanut flour and peanut protein isolate by Flavorzyme.

    PubMed

    Zheng, Lin; Zhao, Yijun; Xiao, Chuqiao; Sun-Waterhouse, Dongxiao; Zhao, Mouming; Su, Guowan

    2015-02-01

    Both defatted peanut flour (DPF) and peanut protein isolate (PPI) are widely used to prepare peanut protein hydrolysates. To compare their enzymatic hydrolysis efficiencies, DPF and PPI were hydrolysed by Alcalase, Neutrase, Papain, Protamex and Flavorzyme. Alcalase and Flavorzyme were found to be the most efficient proteases to hydrolyse both DPF and PPI. The efficiency was comparable to each other when using Alcalase, while PPI was hydrolysed less efficiently than DPF when using Flavorzyme. Analysis of changes in the protein solubility, subunit and conformation, and amino acid composition of DPF, PPI and their Flavorzyme hydrolysis residues indicated that the PPI preparation process had minimal effect on it, but peptide aggregation via non-covalent bonding (including hydrophobic interactions and hydrogen bonds) during hydrolysis and/or thermal treatment after hydrolysis were likely responsible for the reduced hydrolysis efficiency of PPI by Flavorzyme.

  2. Improved enzymatic hydrolysis of lignocellulosic biomass through pretreatment with plasma electrolysis.

    PubMed

    Gao, Jing; Chen, Li; Zhang, Jian; Yan, Zongcheng

    2014-11-01

    A comprehensive research on plasma electrolysis as pretreatment method for water hyacinth (WH) was performed based on lignin content, crystalline structure, surface property, and enzymatic hydrolysis. A large number of active particles, such as HO and H2O2, generated by plasma electrolysis could decompose the lignin of the biomass samples and reduce the crystalline index. An efficient pretreatment process made use of WH pretreated at a load of 48 wt% (0.15-0.18 mm) in FeCl3 solution for 30 min at 450 V. After the pretreatment, the sugar yield of WH was increased by 126.5% as compared with unpretreated samples. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Thermo-chemical pretreatment and enzymatic hydrolysis for enhancing saccharification of catalpa sawdust.

    PubMed

    Jin, Shuguang; Zhang, Guangming; Zhang, Panyue; Li, Fan; Fan, Shiyang; Li, Juan

    2016-04-01

    To improve the reducing sugar production from catalpa sawdust, thermo-chemical pretreatments were examined and the chemicals used including NaOH, Ca(OH)2, H2SO4, and HCl. The hemicellulose solubilization and cellulose crystallinity index (CrI) were significantly increased after thermo-alkaline pretreatments, and the thermo-Ca(OH)2 pretreatment showed the best improvement for reducing sugar production comparing to other three pretreatments. The conditions of thermo-Ca(OH)2 pretreatment and enzymatic hydrolysis were systematically optimized. Under the optimal conditions, the reducing sugar yield increased by 1185.7% comparing to the control. This study indicates that the thermo-Ca(OH)2 pretreatment is ideal for the saccharification of catalpa sawdust and that catalpa sawdust is a promising raw material for biofuel. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Pretreatment of Eucalyptus in biphasic system for furfural production and accelerated enzymatic hydrolysis.

    PubMed

    Zhang, Xiudong; Bai, Yuanyuan; Cao, Xuefei; Sun, Runcang

    2017-08-01

    Herein, an efficient biphasic pretreatment process was developed to improve the production of furfural (FF) and glucose from Eucalyptus. The influence of formic acid and NaCl on FF production from xylose in water and various biphasic systems was investigated. Results showed that the addition of formic acid and NaCl significantly promoted the FF yield, and the biphasic system of MIBK (methyl isobutyl ketone)/water exhibited the best performance for FF production. Then the Eucalyptus was pretreated in the MIBK/water system, and a maximum FF yield of 82.0% was achieved at 180°C for 60min. Surface of the pretreated Eucalyptus became relatively rough and loose, and its crystallinity index increased obviously due to the removal of hemicelluloses and lignin. The pretreated Eucalyptus samples showed much higher enzymatic hydrolysis rates (26.2-70.7%) than the raw Eucalyptus (14.5%). Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Preparation and characterization of phenol-formaldehyde adhesives modified with enzymatic hydrolysis lignin.

    PubMed

    Jin, Yanqiao; Cheng, Xiansu; Zheng, Zuanbin

    2010-03-01

    Phenol-formaldehyde (PF) adhesives modified with enzymatic hydrolysis lignin (EHL) were synthesized by a one-step process. The phenol component of the PF adhesives was partially substituted by EHL extracted from the residues of cornstalks used to produce bio-ethanol. The EHL-PF adhesives were used to prepare plywoods by hot-pressing. The pH value, viscosity, solid content, free phenol content, free formaldehyde content and brominable substance content of EHL-PF resins were investigated. The bonding strengths of the plywoods were determined, and the influences of the replacement percentage of phenol by EHL (a) and the NaOH content (b) on the properties of the adhesives were investigated. The results showed that the performance of the modified adhesives and the plywoods glued with them almost met the Chinese National Standard (GB/T 14732-2006) for first grade plywood when 20 wt% of the phenol was replaced by EHL.

  6. Enhancement of enzymatic hydrolysis of wheat straw by gamma irradiation-alkaline pretreatment

    NASA Astrophysics Data System (ADS)

    Yin, Yanan; Wang, Jianlong

    2016-06-01

    Pretreatment of wheat straw with gamma irradiation and NaOH was performed to enhance the enzymatic hydrolysis of wheat straw for production of reducing sugar. The results showed that the irradiation of wheat straw at 50 kGy decreased the yield of reducing sugar, however, the reducing sugar yield increased with increasing dose from 50 kGy to 400 kGy. The irradiation of wheat straw at 100 kGy can significantly decrease NaOH consumption and treatment time. The reducing sugar yield could reach 72.67% after irradiation at 100 kGy and 2% NaOH treatment for 1 h. The combined pretreatment of wheat straw by gamma radiation and NaOH immersion can increase the solubilization of hemicellulose and lignin as well as the accessible surface area for enzyme molecules.

  7. The role of pretreatment in improving the enzymatic hydrolysis of lignocellulosic materials.

    PubMed

    Sun, Shaoni; Sun, Shaolong; Cao, Xuefei; Sun, Runcang

    2016-01-01

    Lignocellulosic materials are among the most promising alternative energy resources that can be utilized to produce cellulosic ethanol. However, the physical and chemical structure of lignocellulosic materials forms strong native recalcitrance and results in relatively low yield of ethanol from raw lignocellulosic materials. An appropriate pretreatment method is required to overcome this recalcitrance. For decades various pretreatment processes have been developed to improve the digestibility of lignocellulosic biomass. Each pretreatment process has a different specificity on altering the physical and chemical structure of lignocellulosic materials. In this paper, the chemical structure of lignocellulosic biomass and factors likely affect the digestibility of lignocellulosic materials are discussed, and then an overview about the most important pretreatment processes available are provided. In particular, the combined pretreatment strategies are reviewed for improving the enzymatic hydrolysis of lignocellulose and realizing the comprehensive utilization of lignocellulosic materials. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effects of NIPAm polymer additives on the enzymatic hydrolysis of Avicel and pretreated Miscanthus.

    PubMed

    Mackenzie, Katherine J; Francis, Matthew B

    2014-09-01

    There is currently much interest in the economic use of cellulosic biomass as a source of renewable fuels. This process typically involves the enzymatic hydrolysis of plant matter to afford soluble sugars for subsequent fermentation steps. The cost of cellulase enzymes presents a critical barrier to the commercialization of these processes. In this work, we demonstrate that a new family of polymer additives based on NIPAm can increase enzyme performance substantially. When applied to an industrially relevant combination of enzymes and lignin-containing biomass, polymer additives allow a 60% reduction in enzyme loading to achieve the same level of saccharification. Evidence presented herein suggests that these polymers function through multiple mechanisms, including (1) preventing enzyme denaturation through shear and interfacial interactions, (2) preventing non-productive adsorption to lignin, and (3) altering the cellulose structure. An advantage of these polymers over other additives is their thermoresponsive behavior, enabling their recovery and reuse. © 2014 Wiley Periodicals, Inc.

  9. Hydrothermal pretreatment enhanced enzymatic hydrolysis and glucose production from oil palm biomass.

    PubMed

    Zakaria, Mohd Rafein; Hirata, Satoshi; Hassan, Mohd Ali

    2015-01-01

    The present works investigate hydrothermal pretreatment of oil palm empty fruit bunch and oil palm frond fiber in a batch tube reactor system with temperature and time range from 170 to 250°C and 10 to 20min, respectively. The behavior of soluble sugars, acids, furans, and phenols dramatically changed over treatment severities as determined by HPLC. The cellulose-rich treated solids were analyzed by SEM, WAXD, and BET surface area. Enzymatic hydrolysis was performed from both pretreated slurries and washed solid, and data obtained suggested that tannic acid derived from lignin degradation was a potential cellulase inhibitor. Both partial removal of hemicellulose and migration of lignin during hydrothermal pretreatment caused structural changes on the cellulose-hemicellulose-lignin matrix, resulting in the opening and expansion of specific surface area and pore volume. The current results provided important factors that maximize conversion of cellulose to glucose from oil palm biomass by hydrothermal process.

  10. Developmental Transition from Enzymatic to Acid Hydrolysis of Sucrose in Acid Limes (Citrus aurantifolia).

    PubMed

    Echeverria, E

    1990-01-01

    The sucrose breakdown mechanisms in juice sacs of acid lime (Citrus aurantifolia [Christm.] Swing.) were investigated throughout fruit development. All three enzymes of sucrose catabolism (sucrose synthase, acid, and alkaline invertase) are present during the initial stages. The activities of these enzymes declined rapidly and disappeared by stage 5 (80% development) but not before vacuolar pH had decreased to approximately 2.5. At this stage, sucrose breakdown occurs by acid hydrolysis. By attaining a vacuolar pH of 2.5 prior to enzyme disappearance, the cell maintains a continuous ability to break down sucrose throughout ontogeny. Thus, acid limes possess a unique and coordinated system for sucrose breakdown that involves both enzymatic and nonenzymatic pathways.

  11. Developmental Transition from Enzymatic to Acid Hydrolysis of Sucrose in Acid Limes (Citrus aurantifolia) 1

    PubMed Central

    Echeverria, Ed

    1990-01-01

    The sucrose breakdown mechanisms in juice sacs of acid lime (Citrus aurantifolia [Christm.] Swing.) were investigated throughout fruit development. All three enzymes of sucrose catabolism (sucrose synthase, acid, and alkaline invertase) are present during the initial stages. The activities of these enzymes declined rapidly and disappeared by stage 5 (80% development) but not before vacuolar pH had decreased to approximately 2.5. At this stage, sucrose breakdown occurs by acid hydrolysis. By attaining a vacuolar pH of 2.5 prior to enzyme disappearance, the cell maintains a continuous ability to break down sucrose throughout ontogeny. Thus, acid limes possess a unique and coordinated system for sucrose breakdown that involves both enzymatic and nonenzymatic pathways. PMID:16667241

  12. Characterization of sugar beet pectic-derived oligosaccharides obtained by enzymatic hydrolysis.

    PubMed

    Combo, Agnan Marie Michel; Aguedo, Mario; Quiévy, Nicolas; Danthine, Sabine; Goffin, Dorothée; Jacquet, Nicolas; Blecker, Christophe; Devaux, Jacques; Paquot, Michel

    2013-01-01

    Three pectic oligosaccharides (POS) obtained by enzymatic hydrolysis of sugar beet pectin by combining endopolygalacturonase and pectinmethylesterase, were characterized using high performance liquid chromatography, thermogravimetric analysis, Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffraction. According to chromatographic analyses, POS are composed of mixture of polymers with different molecular weights and different galacturonic acid contents. The thermal analysis showed no major variation in thermal behavior regarding POS composition but showed that POS were more sensitive to thermal degradation than the parent pectin as well as the deesterified pectin. No change in composition of the gaseous products was obtained through TGA-FTIR analysis. The X-ray pattern of POS clearly indicated a considerable decrease in crystallinity when compared to the native pectin. Thus, thermal characterization of POS may have practical repercussions if the formulation in which POS is incorporated is submitted to a high temperature treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Process for enzymatic hydrolysis of fatty acid triglycerides with oat caryopses

    SciTech Connect

    Hammond, E.G.; Lee, I.

    1992-02-18

    This patent describes the process for enzymatic hydrolysis of fatty acid triglycerides to obtain free fatty acids and glycerol. It comprises: increasing the water content of dehulled whole oat caryopses to a total water content of 17 to 44% the thus moistened caryopses having active oat lipase associated with the outer surfaces thereof; contacting the moistened whole caryopses with a liquid medium, continuing the contacting until at least 20% by volume of the triglyceride reactant has been hydrolyzed to free fatty acids and glycerol, most of the free fatty acids dissolving in the oil phase external to the caryopses and most of the glycerol being absorbed into the water within the caryopses; and separating the glycerol-containing caryopses from the fatty acid-containing oil phase.

  14. Using FTIR to predict saccharification from enzymatic hydrolysis of alkali-pretreated biomasses.

    PubMed

    Sills, Deborah L; Gossett, James M

    2012-02-01

    Fourier transform infrared, attenuated total reflectance (FTIR-ATR) spectroscopy combined with partial least squares (PLS) regression accurately predicted 72-h glucose and xylose conversions (g sugars/100 g potential sugars) and yields (g sugars/100 g dry solids) from cellulase-mediated hydrolysis of alkali-pretreated lignocellulose. Six plant biomasses that represent a variety of potential biofuel feedstocks--two switchgrass cultivars, big bluestem grass, a low-impact, high-diversity mixture of 32 species of prairie biomasses, mixed hardwood, and corn stover--were subjected to four levels of low-temperature NaOH pretreatment to produce 24 samples with a wide range of potential digestibility. PLS models were constructed by correlating FTIR spectra of pretreated samples to measured values of gluose and xylose conversions and yields. Variable selection, based on 90% confidence intervals of regression-coefficient matrices, improved the predictive ability of the models, while simplifying them considerably. Final models predicted sugar conversions with coefficient of determination for cross-validation (Q(2)) values of 0.90 for glucose and 0.89 for xylose, and sugar yields with Q(2) values of 0.92 for glucose and 0.91 for xylose. The sugar-yield models are noteworthy for their ability to predict enzymatic saccharification per mass dry solids without a priori knowledge of the composition of the solids. All peaks retained in the final regression coefficient matrices were previously assigned to chemical bonds and functional groups in lignocellulose, demonstrating that the models were based on real chemical information. This study demonstrates that FTIR spectroscopy combined with PLS regression can be used to rapidly estimate sugar conversions and yields from enzymatic hydrolysis of pretreated plant biomass. Copyright © 2011 Wiley Periodicals, Inc.

  15. Yield-determining factors in high-solids enzymatic hydrolysis of lignocellulose

    PubMed Central

    Kristensen, Jan B; Felby, Claus; Jørgensen, Henning

    2009-01-01

    Background Working at high solids (substrate) concentrations is advantageous in enzymatic conversion of lignocellulosic biomass as it increases product concentrations and plant productivity while lowering energy and water input. However, for a number of lignocellulosic substrates it has been shown that at increasing substrate concentration, the corresponding yield decreases in a fashion which can not be explained by current models and knowledge of enzyme-substrate interactions. This decrease in yield is undesirable as it offsets the advantages of working at high solids levels. The cause of the 'solids effect' has so far remained unknown. Results The decreasing conversion at increasing solids concentrations was found to be a generic or intrinsic effect, describing a linear correlation from 5 to 30% initial total solids content (w/w). Insufficient mixing has previously been shown not to be involved in the effect. Hydrolysis experiments with filter paper showed that neither lignin content nor hemicellulose-derived inhibitors appear to be responsible for the decrease in yields. Product inhibition by glucose and in particular cellobiose (and ethanol in simultaneous saccharification and fermentation) at the increased concentrations at high solids loading plays a role but could not completely account for the decreasing conversion. Adsorption of cellulases was found to decrease at increasing solids concentrations. There was a strong correlation between the decreasing adsorption and conversion, indicating that the inhibition of cellulase adsorption to cellulose is causing the decrease in yield. Conclusion Inhibition of enzyme adsorption by hydrolysis products appear to be the main cause of the decreasing yields at increasing substrate concentrations in the enzymatic decomposition of cellulosic biomass. In order to facilitate high conversions at high solids concentrations, understanding of the mechanisms involved in high-solids product inhibition and adsorption inhibition

  16. Sequential pretreatment strategies under mild conditions for efficient enzymatic hydrolysis of wheat straw.

    PubMed

    Sanchez, Arturo; Gil, Juan Carlos; Rojas-Rejón, Oscar A; de Alba, Ana P; Medina, Andrea; Flores, Roberto; Puente, Ramón

    2015-06-01

    This work studies the sequential execution of dilute sulfuric acid (DAP) (0.1-0.75 %, v/v) and dilute sodium hydroxide (AKP) (0.25-3 %, w/v) [i.e., DAP followed by AKP (DAP+AKP) and vice versa (AKP+DAP)] at low temperatures (<121 °C) and short reaction times (5-60 min) for maximizing sugar recovery in the enzymatic hydrolysis of wheat straw with low enzyme dosage. The pretreatment effectiveness was measured by the sum of the severity factors of both pretreatments and the saccharification yield achieved in the subsequent stage of enzymatic hydrolysis. Degradation compounds were quantified and mass balance calculations were carried out for each pretreatment sequence to verify the correct account of the input biomass and output products. Results show that sequential pretreatments (AKP+DAP and DAP+AKP) had a positive effect in enzyme accessibility thus improving monosaccharide yields compared to single DAP and AKP pretreatments. DAP+AKP achieved a high xylose yield (ca. 0.867 of theoretical) at the DAP stage, while no xylose monosaccharides were detected in the subsequent AKP. After enzyme saccharification of double-pretreated solids, the total monosaccharide yield was 0.786 (of theoretical). For AKP+DAP sequence, lower results were obtained (total monosaccharide yield 0.783 of theoretical). Sequential pretreatments total yields increased by 21 % compared to single pretreatments. AKP removed more than half of the lignin from the wheat straw in all cases. Acid and alkali concentrations played a relevant role in all pretreatment sequences, while reaction time and temperature were less important with an almost-linear effect on the total monosaccharide yields.

  17. Torque measurements reveal large process differences between materials during high solid enzymatic hydrolysis of pretreated lignocellulose

    PubMed Central

    2012-01-01

    Background A common trend in the research on 2nd generation bioethanol is the focus on intensifying the process and increasing the concentration of water insoluble solids (WIS) throughout the process. However, increasing the WIS content is not without problems. For example, the viscosity of pretreated lignocellulosic materials is known to increase drastically with increasing WIS content. Further, at elevated viscosities, problems arise related to poor mixing of the material, such as poor distribution of the enzymes and/or difficulties with temperature and pH control, which results in possible yield reduction. Achieving good mixing is unfortunately not without cost, since the power requirements needed to operate the impeller at high viscosities can be substantial. This highly important scale-up problem can easily be overlooked. Results In this work, we monitor the impeller torque (and hence power input) in a stirred tank reactor throughout high solid enzymatic hydrolysis (< 20% WIS) of steam-pretreated Arundo donax and spruce. Two different process modes were evaluated, where either the impeller speed or the impeller power input was kept constant. Results from hydrolysis experiments at a fixed impeller speed of 10 rpm show that a very rapid decrease in impeller torque is experienced during hydrolysis of pretreated arundo (i.e. it loses its fiber network strength), whereas the fiber strength is retained for a longer time within the spruce material. This translates into a relatively low, rather WIS independent, energy input for arundo whereas the stirring power demand for spruce is substantially larger and quite WIS dependent. By operating the impeller at a constant power input (instead of a constant impeller speed) it is shown that power input greatly affects the glucose yield of pretreated spruce whereas the hydrolysis of arundo seems unaffected. Conclusions The results clearly highlight the large differences between the arundo and spruce materials, both in terms of

  18. Ammonia Fiber Expansion Pretreatment and Enzymatic Hydrolysis on Two Different Growth Stages of Reed Canarygrass

    NASA Astrophysics Data System (ADS)

    Bradshaw, Tamika C.; Alizadeh, Hasan; Teymouri, Farzaneh; Balan, Venkatesh; Dale, Bruce E.

    Plant materials from the vegetative growth stage of reed canarygrass and the seed stage of reed canarygrass are pretreated by ammonia fiber expansion (AFEX) and enzymatically hydrolyzed using 15 filter paper units (FPU) cellulase/g glucan to evaluate glucose and xylose yields. Percent conversions of glucose and xylose, effects of temperature and ammonia loading, and hydrolysis profiles are analyzed to determine the most effective AFEX treatment condition for each of the selected materials. The controls used in this study were untreated samples of each biomass material. All pretreatment conditions tested enhanced enzyme digestibility and improved sugar conversions for reed canarygrass compared with their untreated counterparts. Based on 168 h hydrolysis results using 15 FPU Spezyme CP cellulase/g glucan the most effective AFEX treatment conditions were determined as: vegetative growth stage of reed canarygrass—100°C, 60% moisture content, 1.2∶1 kg ammonia/kg of dry matter (86% glucose and 78% xylose) and seed stage of reed canarygrass—100°C, 60% moisture content, 0.8∶1 kg ammonia/kg of dry matter (89% glucose and 81% xylose). Supplementation by commercial Multifect 720 xylanase along with cellulase further increased both glucose and xylose yields by 10-12% at the most effective AFEX conditions.

  19. Sulfuric Acid Pretreatment and Enzymatic Hydrolysis of Photoperiod Sensitvie Sorghum for Ethanol Production

    SciTech Connect

    F Xu; Y Shi; X Wu

    2011-12-31

    Photoperiod sensitive (PS) sorghum, with high soluble sugar content, high mass yield and high drought tolerance in dryland environments, has great potential for bioethanol production. The effect of diluted sulfuric acid pretreatment on enzymatic hydrolysis was investigated. Hydrolysis efficiency increased from 78.9 to 94.4% as the acid concentration increased from 0.5 to 1.5%. However, the highest total glucose yield (80.3%) occurred at the 1.0% acid condition because of the significant cellulose degradation at the 1.5% concentration. Synchrotron wide-angle X-ray diffraction was used to study changes of the degree of crystallinity. With comparison of cellulosic crystallinity and adjusted cellulosic crystallinity, the crystalline cellulose decreased after low acidic concentration (0.5%) applied, but did not change significantly, as the acid concentration increased. Scanning electron microscopy was also employed to understand how the morphological structure of PS sorghum changed after pretreatment. Under current processing conditions, the total ethanol yield is 74.5% (about 0.2 g ethanol from 1 g PS sorghum). A detail mass balance was also provided.

  20. Effect of [Emim]Ac pretreatment on the structure and enzymatic hydrolysis of sugarcane bagasse cellulose.

    PubMed

    Bian, Jing; Peng, Feng; Peng, Xiao-Peng; Xiao, Xiao; Peng, Pai; Xu, Feng; Sun, Run-Cang

    2014-01-16

    Effect of ionic liquid pretreatment on enzymatic hydrolysis of cellulose was investigated in terms of the changes in the chemical and physical structure of the preparation. In this case, original cellulose isolated from sugarcane bagasse was subjected to ionic liquid ([Emim]Ac) dissolution at a mild temperature (90 °C) followed by regeneration in water and subsequently hydrolyzed by commercial cellulases. The original and regenerated cellulose were thoroughly characterized by XRD, FT-IR, CP/MAS (13)C NMR, and SEM. It was found that the original cellulose experienced an increase in glucose content from 80.0-83.3% to 91.6-92.8%, a decrease in the degree of polymerization from 974-1039 to 511-521, a crystal transformation from cellulose I to cellulose II, as well as an increase of surface area during the pretreatment. The results suggested that pretreatment led to effective disruption of cellulose for subsequent enzyme hydrolysis as evidenced by a high glucose conversion yield of 95.2%.

  1. Urea enzymatic hydrolysis reaction: optimization by response surface methodology based on potentiometric measurements.

    PubMed

    Deyhimi, Farzad; Bajalan, Maryam

    2008-11-01

    The enzymatic hydrolysis reaction of urea by urease is optimized in this work by the chemometric response surface methodology (RSM), based on an initial rate potentiometric measurement using an NH(4)(+) ion-selective electrode (ISE). In this investigation, the ranges of critical variables determined by a preliminary "one at a time" (OVAT) procedure were used as input for the subsequent RSM chemometric analysis. The RSM quadratic response was found to be quite appropriate for modeling and optimization of the hydrolysis reaction as illustrated by the relatively high value of the determination coefficient (R(2)=90.1%), along with the satisfactory results obtained by the analysis of variance (ANOVA). All the evaluated analytical characteristics of the optimized method such as: the linear calibration curve, the upper and lower detection limits, the within-day precisions at low and at high levels, the assay recovery in pool serum media, along with the activation kinetic parameters, were also reported. Further, in order to check the quality of the optimization and the validity of the model, the assay of urea, both in aqueous laboratory and human serum samples, were performed. It has to be noted that the kinetic initial rate measurement method used in this work, permitted to overcome the general problem of NH(4)(+) ISE low selectivity against Na(+) and K(+) interfering ions in real samples.

  2. Kinetic analysis of two-phase enzymatic hydrolysis of hemicellulose of xylan type.

    PubMed

    Dutta, Sajal Kanti; Chakraborty, Saikat

    2015-12-01

    We present a coupled experimental and theoretical framework for quantifying the kinetics of two-phase enzymatic hydrolysis of hemicellulose. For xylan loading of 1-5mg/ml, the nature of inhibition by the product xylose (non-competitive), the kinetic constants (Km=3.93 mg/ml, Vmax=0.0252 mg/ml/min) and the xylose inhibition constant (Kx=0.122 mg/ml) are experimentally determined. Our multi-step two-phase kinetic model incorporating enzyme adsorption to the solid substrate and non-competitive product inhibition is simulated using our kinetic data and validated against our experimentally measured temporal dynamics of xylose and reducing sugars. Further experiments show that higher substrate loading reduces the specific adsorption of the endoxylanase to the solid xylan and the enzyme's solid-liquid distribution ratio, which decelerates the solid hydrolysis and accelerates the liquid phase reactions. Thus, the xylose yield increases with substrate loading, which increases product inhibition and decreases reducing sugar yields. An operating cost analysis gives 3mg/ml as the optimal substrate loading. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Sulfuric acid pretreatment and enzymatic hydrolysis of photoperiod sensitive sorghum for ethanol production.

    PubMed

    Xu, Feng; Shi, Yong-Cheng; Wu, Xiaorong; Theerarattananoon, Karnnalin; Staggenborg, Scott; Wang, Donghai

    2011-05-01

    Photoperiod sensitive (PS) sorghum, with high soluble sugar content, high mass yield and high drought tolerance in dryland environments, has great potential for bioethanol production. The effect of diluted sulfuric acid pretreatment on enzymatic hydrolysis was investigated. Hydrolysis efficiency increased from 78.9 to 94.4% as the acid concentration increased from 0.5 to 1.5%. However, the highest total glucose yield (80.3%) occurred at the 1.0% acid condition because of the significant cellulose degradation at the 1.5% concentration. Synchrotron wide-angle X-ray diffraction was used to study changes of the degree of crystallinity. With comparison of cellulosic crystallinity and adjusted cellulosic crystallinity, the crystalline cellulose decreased after low acidic concentration (0.5%) applied, but did not change significantly, as the acid concentration increased. Scanning electron microscopy was also employed to understand how the morphological structure of PS sorghum changed after pretreatment. Under current processing conditions, the total ethanol yield is 74.5% (about 0.2 g ethanol from 1 g PS sorghum). A detail mass balance was also provided.

  4. Enzymatic kinetic parameters for polyfluorinated alkyl phosphate hydrolysis by alkaline phosphatase.

    PubMed

    Jackson, Derek A; Mabury, Scott A

    2012-09-01

    The hydrolysis kinetics of three polyfluorinated alkyl phosphate monoesters (monoPAPs), differing in fluorinated chain length, were measured using bovine intestinal alkaline phosphatase to catalyze the reaction. Kinetic values were also measured for analogous hydrogenated phosphate monoesters to elucidate the effects of the fluorinated chain on the rate of enzymatic hydrolysis. Michaelis constants (K(m)) were obtained by a competition kinetics technique in the presence of p-nitrophenyl phosphate (PNPP) using UV-vis spectroscopy. Compared with K(m) (PNPP), Michaelis constants for monoPAPs ranged from 0.9 to 2.1 compared with hydrogenated phosphates, which ranged from 4.0 to 13.0. Apparent bimolecular rate constants (k(cat)/K(m)) were determined by monitoring rates of product alcohol formation at low substrate concentrations using gas chromatography-mass spectrometry. The experimental values for k(cat)/K(m) averaged as 1.1 × 10(7) M(-1) s(-1) for monoPAPs compared with 3.8 × 10(5) M(-1) s(-1) for hexyl phosphate. This suggests that the electron-withdrawing nature of the fluorinated chain enhanced the alcohol leaving group ability. The results were used in a simple model to suggest that monoPAPs in a typical mammalian digestive tract would hydrolyze in approximately 100 s, supporting a previous study that showed its absence after a dosing study in rats.

  5. Biological pretreatment of corn stover with ligninolytic enzyme for high efficient enzymatic hydrolysis.

    PubMed

    Wang, Feng-Qin; Xie, Hui; Chen, Wei; Wang, En-Tao; Du, Feng-Guang; Song, An-Dong

    2013-09-01

    Aiming at increasing the efficiency of transferring corn stover into sugars, a biological pretreatment was developed and investigated in this study. The protocol was characterized by the pretreatment with crude ligninolytic enzymes from Phanerochete chrysosporium and Coridus versicolor to break the lignin structure in corn stover, followed by a washing procedure to eliminate the inhibition of ligninolytic enzyme on cellulase. By a 2 d-pretreatment, sugar yield from corn stover hydrolysis could be increased by 50.2% (up to 323 mg/g) compared with that of the control. X-ray diffractometry and FT-IR analysis revealed that biological pretreatment could partially remove the lignin of corn stover, and consequently enhance the enzymatic hydrolysis efficiency of cellulose and hemeicellulose. In addition, the amount of microbial inhibitors, such as acetic acid and furfural, were much lower in biological pretreatment than that in acid pretreatment. This study provided a promising pretreatment method for biotransformation of corn stovers. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Physico-chemical pretreatment and enzymatic hydrolysis of cotton stalk for ethanol production by Saccharomyces cerevisiae.

    PubMed

    Singh, Anita; Bajar, Somvir; Bishnoi, Narsi R

    2017-11-01

    The aim of this work was to study the physico-chemical pretreatment and enzymatic hydrolysis of cotton stalk for ethanol production by Saccharomyces cerevisiae. Firstly, factors affecting pretreatment were screened out by Plackett-Burman design (PBD) and most significant factors were further optimized by Box-Behnken design (BBD). As shown by experimental study, most significant factors were FeCl3 concentration (FC), irradiation time (IT) and substrate concentration (SC) affecting pretreatment of cotton stalk among all studied factors. Under optimum conditions of pretreatment FC 0.15mol/l, IT 20min and SC 55g/l, the release of reducing sugar was 6.6g/l. Hydrolysis of pretreated cotton stalk was done by crude on-site produced enzymes and hydrolysate was concentrated. Ethanol production by Saccharomyces cerevisiae using concentrated cotton stalk hydrolysate was 9.8gp/l, with ethanol yield 0.37gp/gs on consumed sugars. The data indicated that microwave FeCl3 pretreated cotton stalk hydrolyses by crude unprocessed enzyme cocktail was good, and ethanol can be produced by fermentation of hydrolysate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Statistical Evaluation of HTS Assays for Enzymatic Hydrolysis of β-Keto Esters

    PubMed Central

    Dold, S. -M.; Zimmermann, S.; Hamacher, K.; Schmitz, K.; Rudat, J.

    2016-01-01

    β-keto esters are used as precursors for the synthesis of β-amino acids, which are building blocks for some classes of pharmaceuticals. Here we describe the comparison of screening procedures for hydrolases to be used for the hydrolysis of β-keto esters, the first step in the preparation of β-amino acids. Two of the tested high throughput screening (HTS) assays depend on coupled enzymatic reactions which detect the alcohol released during ester hydrolysis by luminescence or absorption. The third assay detects the pH shift due to acid formation using an indicator dye. To choose the most efficient approach for screening, we assessed these assays with different statistical methods—namely, the classical Z’-factor, standardized mean difference (SSMD), the Kolmogorov-Smirnov-test, and t-statistics. This revealed that all three assays are suitable for HTS, the pH assay performing best. Based on our data we discuss the explanatory power of different statistical measures. Finally, we successfully employed the pH assay to identify a very fast hydrolase in an enzyme-substrate screening. PMID:26730596

  8. Hydrothermal processing and enzymatic hydrolysis of sorghum bagasse for fermentable carbohydrates production.

    PubMed

    Dogaris, Ioannis; Karapati, Sofia; Mamma, Diomi; Kalogeris, Emmanuel; Kekos, Dimitris

    2009-12-01

    Untreated and hydrothermally treated sorghum bagasse (SB) was hydrolyzed to simple sugars by the synergistic action of cellulases and hemicellulases produced by the fungi Fusarium oxysporum and Neurospora crassa. Synergism between the two lignocellulolytic systems was maximized with the application of higher fraction of N. crassa enzymes. Hydrothermolysis of SB was studied at a wide range of treatment times and temperatures. At intense pretreatment conditions (210 degrees C for 20 min; logR(0)=4.54), the residual hemicellulose percentage was 17.45%, while formation of inhibitory products, 5-hydromethyl-furfural (HMF), furfural, acetic and formic acid, (0.21, 0.51, 3.36 and 1.80 g/l, respectively) remained in acceptable levels. Maximum conversion of cellulose and total polysaccharides of the untreated SB were 23.18% and 18.79%, respectively. Combining hydrothermal treatment and enzymatic hydrolysis of released oligosaccharides and insoluble solids resulted in improvement of cellulose (approximately 15% increase) and total polysaccharides (two fold) hydrolysis compared to that of untreated SB.

  9. Kinetics of lime pretreatment of sugarcane bagasse to enhance enzymatic hydrolysis.

    PubMed

    Fuentes, Laura L G; Rabelo, Sarita C; Filho, Rubens Maciel; Costa, Aline C

    2011-03-01

    The objective of this work was to determine the optimum conditions of sugarcane bagasse pretreatment with lime to increase the enzymatic hydrolysis of the polysaccharide component and to study the delignification kinetics. The first stage was an evaluation of the influence of temperature, reaction time, and lime concentration in the pretreatment performance measured as glucose release after hydrolysis using a 2(3) central composite design and response surface methodology. The maximum glucose yield was 228.45 mg/g raw biomass, corresponding to 409.9 mg/g raw biomass of total reducing sugars, with the pretreatment performed at 90°C, for 90 h, and with a lime loading of 0.4 g/g dry biomass. The enzymes loading was 5.0 FPU/dry pretreated biomass of cellulase and 1.0 CBU/dry pretreated biomass of β-glucosidase. Kinetic data of the pretreatment were evaluated at different temperatures (60°C, 70°C, 80°C, and 90°C), and a kinetic model for bagasse delignification with lime as a function of temperature was determined. Bagasse composition (cellulose, hemicellulose, and lignin) was measured, and the study has shown that 50% of the original material was solubilized, lignin and hemicellulose were selectively removed, but cellulose was not affected by lime pretreatment in mild temperatures (60-90°C). The delignification was highly dependent on temperature and duration of pretreatment.

  10. Biorefining of waste paper biomass: increasing the concentration of glucose by optimising enzymatic hydrolysis.

    PubMed

    Elliston, Adam; Collins, Samuel R A; Faulds, Craig B; Roberts, Ian N; Waldron, Keith W

    2014-04-01

    Waste copier paper is a potential substrate for the production of glucose relevant for manufacture of platform chemicals and intermediates, being composed of 51 % glucan. The yield and concentration of glucose arising from the enzymatic saccharification of solid ink-free copier paper as cellulosic substrate was studied using a range of commercial cellulase preparations. The results show that in all cellulase preparations examined, maximum hydrolysis was only achieved with the addition of beta-glucosidase, despite its presence in the enzyme mixtures. With the use of Accellerase® (cellulase), high substrate loading decreased conversion yield. However, this was overcome if the enzyme was added between 12.5 and 20 FPU g substrate(-1). Furthermore, this reaction condition facilitated continual stirring and enabled sequential additions (up to 50 % w/v) of paper to be made to the hydrolysis reaction, degrading nearly all (99 %) of the cellulose fibres and increasing the final concentration of glucose whilst simultaneously making high substrate concentrations achievable. Under optimal conditions (50 °C, pH 5.0, 72 h), digestions facilitate the production of glucose to much improved concentrations of up to 1.33 mol l(-1).

  11. Statistical Evaluation of HTS Assays for Enzymatic Hydrolysis of β-Keto Esters.

    PubMed

    Buß, O; Jager, S; Dold, S-M; Zimmermann, S; Hamacher, K; Schmitz, K; Rudat, J

    2016-01-01

    β-keto esters are used as precursors for the synthesis of β-amino acids, which are building blocks for some classes of pharmaceuticals. Here we describe the comparison of screening procedures for hydrolases to be used for the hydrolysis of β-keto esters, the first step in the preparation of β-amino acids. Two of the tested high throughput screening (HTS) assays depend on coupled enzymatic reactions which detect the alcohol released during ester hydrolysis by luminescence or absorption. The third assay detects the pH shift due to acid formation using an indicator dye. To choose the most efficient approach for screening, we assessed these assays with different statistical methods-namely, the classical Z'-factor, standardized mean difference (SSMD), the Kolmogorov-Smirnov-test, and t-statistics. This revealed that all three assays are suitable for HTS, the pH assay performing best. Based on our data we discuss the explanatory power of different statistical measures. Finally, we successfully employed the pH assay to identify a very fast hydrolase in an enzyme-substrate screening.

  12. Kinetic modeling of enzymatic hydrolysis of pretreated kitchen wastes for enhancing bioethanol production.

    PubMed

    Cekmecelioglu, Deniz; Uncu, Oya N

    2013-03-01

    It is well known that use of low cost and abundant waste materials in microbial fermentations can reduce product costs. Kitchen wastes disposed of in large amounts from cafeterias, restaurants, dining halls, food processing plants, and household kitchens contain high amounts of carbohydrate components such as glucose, starch, and cellulose. Efficient utilization of these sugars is another opportunity to reduce ethanol costs. In this study, the effect of pretreatment methods (hot water, acid solutions, and a control) on enzymatic hydrolysis of kitchen wastes was evaluated using a kinetic modeling approach. Fermentation experiments conducted with and without traditional fermentation nutrients were assessed at constant conditions of pH 4.5 and temperature of 30°C for 48h using commercial dry baker's yeast, Saccharomyces cerevisiae. The control, which involved no treatment, and hot water treated samples gave close glucose concentrations after 6h. The highest and lowest rates of glucose production were found as 0.644 and 0.128 (h(-1)) for the control (or no-pretreated (NPT)) and 1% acid solutions, respectively. The fermentation results indicated that final ethanol concentrations are not significantly improved by adding nutrients (17.2-23.3g/L). Thus, it was concluded that product cost can be lowered to a large extent if (1) kitchen wastes are used as a substrate, (2) no fermentation nutrient is used, and (3) hydrolysis time is applied for about 6h. Further optimization study is needed to increase the yield to higher levels.

  13. Enzymatic hydrolysis of sodium dodecyl sulphate (SDS)-pretreated newspaper for cellulosic ethanol production by Saccharomyces cerevisiae and Pichia stipitis.

    PubMed

    Xin, Fengxue; Geng, Anli; Chen, Ming Li; Gum, Ming Jun Marcus

    2010-10-01

    Fermentation of enzymatic hydrolysate of waste newspaper was investigated for cellulosic ethanol production in this study. Various nonionic and ionic surfactants were applied for waste newspaper pretreatment to increase the enzymatic digestibility. The surfactant-pretreated newspaper was enzymatically digested in 0.05 M sodium citrate buffer (pH 4.8) with varying solid content, filter paper unit loading (FPU/g newspaper), and ratio of filter paper unit/beta-glucosidase unit (FPU/CBU). Newspaper pretreated with the anionic surfactant sodium dodecyl sulphate (SDS) demonstrated the highest sugar yield. The addition of Tween-80 in the enzymatic hydrolysis process enhanced the enzymatic digestibility of newspaper pretreated with all of the surfactants. Enzymatic hydrolysis of SDS-pretreated newspaper with 15% solid content, 15 FPU/g newspaper, and FPU/CBU of 1:4 resulted in a newspaper hydrolysate conditioning 29.07 g/L glucose and 4.08 g/L xylose after 72 h of incubation at 50 degrees C. The fermentation of the enzymatic hydrolysate with Saccharomyces cerevisiae, Pichia stipitis, and their co-culture produced 14.29, 13.45, and 14.03 g/L of ethanol, respectively. Their corresponding ethanol yields were 0.43, 0.41, and 0.42 g/g.

  14. The state of the art in the production of fructose from inulin enzymatic hydrolysis.

    PubMed

    Ricca, Emanuele; Calabrò, Vincenza; Curcio, Stefano; Iorio, Gabriele

    2007-01-01

    The present work reviews the main advancements achieved in the last decades in the study of the fructose production process by inulin enzymatic hydrolysis. With the aim of collecting and clarifying the majority of the knowledge in this area, the research on this subject has been divided in three main parts: a) the characteristics of inulin (the process reactant); b) the properties of the enzyme inulinase and its hydrolytic action; c) the advances in the study of the applications of inulinases in bioreactors for fructose production. Many vegetable sources of inulin are reported, including information about their yields in terms of inulin. The properties of inulin that appear relevant for the process are also summarized, with reference to their vegetable origin. The characteristics of the inulinase enzyme that catalyzes inulin hydrolysis, together with the most relevant information for a correct process design and implementation, are described in the paper. An extended collection of data on microorganisms capable of producing inulinase is reported. The following characteristics and properties of inulinase are highlighted: molecular weight, mode of action, activity and stability with respect to changes in temperature and pH, kinetic behavior and effect of inhibitors. The paper describes in detail the main aspects of the enzyme hydrolysis reaction; in particular, how enzyme and reactant properties can affect process performance. The properties of inulinase immobilized on various supports are shown and compared to those of the enzyme in its native state. Finally, a number of applications of free and immobilized inulinases and whole cells in bioreactors are reported, showing the different operating procedures and reactor types adopted for fructose production from inulin on a laboratory scale.

  15. Enzymatic neutralization of the chemical warfare agent VX: evolution of phosphotriesterase for phosphorothiolate hydrolysis.

    PubMed

    Bigley, Andrew N; Xu, Chengfu; Henderson, Terry J; Harvey, Steven P; Raushel, Frank M

    2013-07-17

    The V-type nerve agents (VX and VR) are among the most toxic substances known. The high toxicity and environmental persistence of VX make the development of novel decontamination methods particularly important. The enzyme phosphotriesterase (PTE) is capable of hydrolyzing VX but with an enzymatic efficiency more than 5 orders of magnitude lower than with its best substrate, paraoxon. PTE has previously proven amenable to directed evolution for the improvement of catalytic activity against selected compounds through the manipulation of active-site residues. Here, a series of sequential two-site mutational libraries encompassing 12 active-site residues of PTE was created. The libraries were screened for catalytic activity against a new VX analogue, DEVX, which contains the same thiolate leaving group of VX coupled to a diethoxyphosphate core rather than the ethoxymethylphosphonate core of VX. The evolved catalytic activity with DEVX was enhanced 26-fold relative to wild-type PTE. Further improvements were facilitated by targeted error-prone PCR mutagenesis of loop-7, and additional PTE variants were identified with up to a 78-fold increase in the rate of DEVX hydrolysis. The best mutant hydrolyzed the racemic nerve agent VX with a value of kcat/Km = 7 × 10(4) M(-1) s(-1), a 230-fold improvement relative to wild-type PTE. The highest turnover number achieved by the mutants created for this investigation was 137 s(-1), an enhancement of 152-fold relative to wild-type PTE. The stereoselectivity for the hydrolysis of the two enantiomers of VX was relatively low. These engineered mutants of PTE are the best catalysts ever reported for the hydrolysis of nerve agent VX.

  16. Performance of coupled enzymatic hydrolysis and membrane separation bioreactor for antihypertensive peptides production from Porphyra yezoensis protein

    USDA-ARS?s Scientific Manuscript database

    To explore more efficient production methods of antihypertensive peptides from Porphyra yezoensis protein, three methods of coupling of enzymatic hydrolysis and membrane separation (CEH-MS) were studied and compared with the traditional EH and offline MS method. The results showed that the conversio...

  17. Biological pretreatment of corn stover with Phlebia brevispora NRRL-13108 for enhanced enzymatic hydrolysis and efficient ethanol production

    USDA-ARS?s Scientific Manuscript database

    Biological pretreatment of lignocellulosic biomass by white-rot fungus can represent a low-cost and eco-friendly alternative to harsh physical, chemical, or physico-chemical pretreatment methods to facilitate enzymatic hydrolysis. In this work, solid state cultivation of corn stover with Phlebia bre...

  18. Forms and lability of phosphorus in algae and aquatic macrophytes characterized by solution 31P NMR coupled with enzymatic hydrolysis

    USDA-ARS?s Scientific Manuscript database

    Increased information on forms and lability of phosphorus (P) in aquatic macrophytes and algae is crucial for better understanding of P biogeochemical cycling in eutrophic lakes. In this work, solution 31P nuclear magnetic resonance (NMR) spectroscopy coupled with enzymatic hydrolysis (EH) was used ...

  19. Acceleration of the Enzymatic Hydrolysis of Corn Stover and Sugar Cane Bagasse Celluloses by Low Intensity Uniform Ultrasound

    USDA-ARS?s Scientific Manuscript database

    The cost-competitive production of bio-ethanol and other biofuels is currently impeded, mostly by high cost and low efficiency of enzymatic hydrolysis of feedstock biomass and especially plant celluloses. Despite substantial reduction in the cost of production of cellulolytic enzymes in recent times...

  20. Cell-type-dependent enzymatic hydrolysis of palm residues: chemical and surface characterization of fibers and parenchyma cells.

    PubMed

    Li, Ning; Liu, Hao; Fu, Shiyu; Chen, Shicheng

    2013-02-01

    Chemical and surface characteristics of sulfite-pretreated royal palm sheath (RPS) fibers and parenchyma cells were investigated in order to study cell-type-dependent biomass hydrolysis by cellulase. Size, chemical composition, cellulose crystallinity and the exposure of cellulose microfibrils in pretreated RPS biomass affected the enzymatic accessibility and digestibility of different cell-type substrates.

  1. Hydrolysis of Miscanthus for bioethanol production using dilute acid presoaking combined with wet explosion pre-treatment and enzymatic treatment.

    PubMed

    Sørensen, Annette; Teller, Philip J; Hilstrøm, Troels; Ahring, Birgitte K

    2008-09-01

    Miscanthus is a high yielding bioenergy crop. In this study we used acid presoaking, wet explosion, and enzymatic hydrolysis to evaluate the combination of the different pre-treatment methods for bioethanol production with Miscanthus. Acid presoaking is primarily carried out in order to remove xylose prior to wet explosion. The acid presoaking extracted 63.2% xylose and 5.2% glucose. Direct enzymatic hydrolysis of the presoaked biomass was found to give only low sugar yields of 24-26% glucose. Wet explosion is a pre-treatment method that combines wet-oxidation and steam explosion. The effect of wet explosion on non-presoaked and presoaked Miscanthus was investigated using both atmospheric air and hydrogen peroxide as the oxidizing agent. All wet explosion pre-treatments showed to have a disrupting effect on the lignocellulosic biomass, making the sugars accessible for enzymatic hydrolysis. The combination of presoaking, wet explosion, and enzymatic hydrolysis was found to give the highest sugar yields. The use of atmospheric air gave the highest xylose yield (94.9% xylose, 61.3% glucose), while hydrogen peroxide gave the highest glucose yield (82.4% xylose, 63.7% glucose).

  2. Effect of liquid hot water pretreatment severity on properties of hardwood lignin and enzymatic hydrolysis of cellulose.

    PubMed

    Ko, Ja Kyong; Kim, Youngmi; Ximenes, Eduardo; Ladisch, Michael R

    2015-02-01

    Lignin, one of the major components of lignocellulosic biomass, plays an inhibitory role on the enzymatic hydrolysis of cellulose. This work examines the role of lignin in pretreated hardwood, where extents of cellulose hydrolysis decrease, rather than increase with increasing severity of liquid hot water pretreatment. Hardwood pretreated with liquid hot water at severities ranging from log Ro  = 8.25 to 12.51 resulted in 80-90% recovery of the initial lignin in the residual solids. The ratio of acid insoluble lignin (AIL) to acid soluble lignin (ASL) increased and the formation of spherical lignin droplets on the cell wall surface was observed as previously reported in the literature. When lignins were isolated from hardwoods pretreated at increasing severities and characterized based on glass transition temperature (Tg ), the Tg of isolated lignins was found to increase from 171 to 180°C as the severity increased from log Ro  = 10.44 to 12.51. The increase in Tg suggested that the condensation reactions of lignin molecules occurred during pretreatment and altered the lignin structure. The contribution of the changes in lignin properties to enzymatic hydrolysis were examined by carrying out Avicel hydrolysis in the presence of isolated lignins. Lignins derived from more severely pretreated hardwoods had higher Tg values and showed more pronounced inhibition of enzymatic hydrolysis.

  3. Solid acid catalysts pretreatment and enzymatic hydrolysis of macroalgae cellulosic residue for the production of bioethanol.

    PubMed

    Tan, Inn Shi; Lee, Keat Teong

    2015-06-25

    The aim of this study is to investigate the technical feasibility of converting macroalgae cellulosic residue (MCR) into bioethanol. An attempt was made to present a novel, environmental friendly and economical pretreatment process that enhances enzymatic conversion of MCR to sugars using Dowex (TM) Dr-G8 as catalyst. The optimum yield of glucose reached 99.8% under the optimal condition for solid acid pretreatment (10%, w/v biomass loading, 4%, w/v catalyst loading, 30min, 120°C) followed by enzymatic hydrolysis (45FPU/g of cellulase, 52CBU/g of β-glucosidase, 50°C, pH 4.8, 30h). The yield of sugar obtained was found more superior than conventional pretreatment process using H2SO4 and NaOH. Biomass loading for the subsequent simultaneous saccharification and fermentation (SSF) of the pretreated MCR was then optimized, giving an optimum bioethanol yield of 81.5%. The catalyst was separated and reused for six times, with only a slight drop in glucose yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Effect of sulfuric and phosphoric acid pretreatments on enzymatic hydrolysis of corn stover.

    PubMed

    Um, Byung-Hwan; Karim, M; Henk, Linda

    2003-01-01

    The pretreatment of corn stover with H2SO4 and H3PO4 was investigated. Pretreatments were carried out from 30 to 120 min in a batch reactor at 121 degrees C, with acid concentrations ranging from 0 to 2% (w/v) at a solid concentration of 5% (w/v). Pretreated corn stover was washed with distilled water until the filtrate was adjusted to pH 7.0, followed by surfactant swelling of the cellulosic fraction in a 0-10% (w/v) solution of Tween-80 at room temperature for 12 h. The dilute acid treatment proved to be a very effective method in terms of hemicellulose recovery and cellulose digestibility. Hemicellulose recovery was 62-90%, and enzymatic digestibility of the cellulose that remained in the solid was >80% with 2% (w/v) acid. In all cases studied, the performance of H2SO4 pretreatment (hemicellulose recovery and cellulose digestibility) was significantly better than obtained with H3PO4. Enzymatic hydrolysis was more effective using surfactant than without it, producing 10-20% more sugar. Furthermore, digestibility was investigated as a function of hemicellulose removal. It was found that digestibility was more directly related to hemicellulose removal than to delignification.

  5. Selective ultrasound-enhanced enzymatic hydrolysis of oleuropein to its aglycon in olive (Olea europaea L.) leaf extracts.

    PubMed

    Delgado-Povedano, María Del Mar; Priego-Capote, Feliciano; Luque de Castro, María Dolores

    2017-04-01

    Hydrolysis of oleuropein, the main phenol in olive (Olea europaea L.) leaf extracts, to oleuropein aglycon and other subsequent products in the hydrolytic pathway can be catalyzed by different enzymes. Three of the most used hydrolases were assayed to catalyze the process, and β-glucosidase from Aspergillus niger was selected. Acceleration of the enzymatic hydrolysis by ultrasound (US) was studied using a Box-Behnken design (duty cycle, amplitude, cycle time) and an oleuropein standard, and the optimum US conditions for achieving maximum yield of oleuropein aglycon were 0.5s/s duty cycle, 50% amplitude and 45s cycle. The method was applied to obtain oleuropein aglycon from commercial and laboratory extracts from olive leaves, which may have a pharmacological use as deduced by its healthy properties. The kinetics of the US-assisted enzymatic hydrolysis was monitored by analysis of the target compounds using liquid chromatography-tandem mass spectrometry.

  6. Using polyvinylpyrrolidone to enhance the enzymatic hydrolysis of lignocelluloses by reducing the cellulase non-productive adsorption on lignin.

    PubMed

    Cai, Cheng; Qiu, Xueqing; Zeng, Meijun; Lin, Meilu; Lin, Xuliang; Lou, Hongming; Zhan, Xuejuan; Pang, Yuxia; Huang, Jinhao; Xie, Lingshan

    2017-03-01

    Polyvinylpyrrolidone (PVP) is an antifouling polymer to resist the adsorption of protein on solid surface. Effects of PVP on the enzymatic hydrolysis of pretreated lignocelluloses and its mechanism were studied. Adding 1g/L of PVP8000, the enzymatic digestibility of eucalyptus pretreated by dilute acid (Eu-DA) was increased from 28.9% to 73.4%, which is stronger than the classic additives, such as PEG, Tween and bovine serum albumin. Compared with PEG4600, the adsorption of PVP8000 on lignin was larger, and the adsorption layer was more stable and hydrophilic. Therefore, PVP8000 reduced 73.1% of the cellulase non-productive adsorption on lignin and enhanced the enzymatic hydrolysis of lignocelluloses greatly. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Enzymatic Hydrolysis of Polyester Thin Films: Real-Time Analysis of Film Mass Changes and Dissipation Dynamics.

    PubMed

    Zumstein, Michael Thomas; Kohler, Hans-Peter E; McNeill, Kristopher; Sander, Michael

    2016-01-05

    Cleavage of ester bonds by extracellular microbial hydrolases is considered a key step during the breakdown of biodegradable polyester materials in natural and engineered systems. Here we present a novel analytical approach for simultaneous detection of changes in the masses and rigidities of polyester thin films during enzymatic hydrolysis using a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D). In experiments with poly(butylene succinate) (PBS) and the lipase of Rhizopus oryzae (RoL), we detected complete hydrolysis of PBS thin films at pH 5 and 40 °C that proceeded through soft and water-rich film intermediates. Increasing the temperature from 20 to 40 °C resulted in a larger increase of the enzymatic hydrolysis rate of PBS than of nonpolymeric dibutyl adipate. This finding was ascribed to elevated accessibility of ester bonds to the catalytic site of RoL due to increasing polyester chain mobility. When the pH of the solution was changed from 5 to 7, initial hydrolysis rates were little affected, while a softer film intermediate that lead to incomplete film hydrolysis was formed. Hydrolysis dynamics of PBS, poly(butylene adipate), poly(lactic acid), and poly(ethylene terephthalate) in assays with RoL showed distinct differences that we attribute to differences in the polyester structure.

  8. Effects of dilute acid pretreatment conditions on enzymatic hydrolysis monomer and oligomer sugar yields for aspen, balsam, and switchgrass.

    PubMed

    Jensen, Jill R; Morinelly, Juan E; Gossen, Kelsey R; Brodeur-Campbell, Michael J; Shonnard, David R

    2010-04-01

    The effects of dilute acid hydrolysis conditions were investigated on total sugar (glucose and xylose) yields after enzymatic hydrolysis with additional analyses on glucose and xylose monomer and oligomer yields from the individual hydrolysis steps for aspen (a hardwood), balsam (a softwood), and switchgrass (a herbaceous energy crop). The results of this study, in the form of measured versus theoretical yields and a severity analysis, show that for aspen and balsam, high dilute acid hydrolysis xylose yields were obtainable at all acid concentrations (0.25-0.75 wt.%) and temperatures (150-175 degrees C) studied as long as reaction time was optimized. Switchgrass shows a relatively stronger dependence on dilute acid hydrolysis acid concentration due to its higher neutralizing mineral content. Maximum total sugar (xylose and glucose; monomer plus oligomer) yields post-enzymatic hydrolysis for aspen, balsam, and switchgrass, were 88.3%, 21.2%, and 97.6%, respectively. In general, highest yields of total sugars (xylose and glucose; monomer plus oligomer) were achieved at combined severity parameter values (log CS) between 2.20 and 2.40 for the biomass species studied.

  9. Enhancing the enzymatic hydrolysis of lignocellulosic biomass by increasing the carboxylic acid content of the associated lignin.

    PubMed

    Nakagame, Seiji; Chandra, Richard P; Kadla, John F; Saddler, Jack N

    2011-03-01

    To assess the effects that the physical and chemical properties of lignin might have on the enzymatic hydrolysis of pretreated lignocellulosic substrates, protease treated lignin (PTL) and cellulolytic enzyme lignin (CEL) fractions, isolated from steam and organosolv pretreated corn stover, poplar, and lodgepole pine, were prepared and characterized. The adsorption of cellulases to the isolated lignin preparations corresponded to a Langmuir adsorption isotherm. It was apparent that, rather than the physical properties of the isolated lignin, the carboxylic acid functionality of the isolated lignin, as determined by FTIR and NMR spectroscopy, had much more of an influence when lignin was added to typical hydrolysis of pure cellulose (Avicel). An increase in the carboxylic content of the lignin preparation resulted in an increased hydrolysis yield. These results suggested that the carboxylic acids within the lignin partially alleviate non-productive binding of cellulases to lignin. To try to confirm this possible mechanism, dehydrogenative polymers (DHP) of monolignols were synthesized from coniferyl alcohol (CA) and ferulic acid (FA), and these model compounds were added to a typical enzymatic hydrolysis of Avicel. The DHP from FA, which was enriched in carboxylic acid groups compared with the DHP from CA, adsorbed a lower mount of cellulases and did not decrease hydrolysis yields when compared to the DHP from CA, which decreased the hydrolysis of Avicel by 8.4%. Thus, increasing the carboxylic acid content of the lignin seemed to significantly decrease the non-productive binding of cellulases and consequently increased the enzymatic hydrolysis of the cellulose. Copyright © 2010 Wiley Periodicals, Inc.

  10. Tissue-specific biomass recalcitrance in corn stover pretreated with liquid hot-water: enzymatic hydrolysis (part 1).

    PubMed

    Zeng, Meijuan; Ximenes, Eduardo; Ladisch, Michael R; Mosier, Nathan S; Vermerris, Wilfred; Huang, Chia-Ping; Sherman, Debra M

    2012-02-01

    Lignin content, composition, distribution as well as cell wall thickness, structures, and type of tissue have a measurable effect on enzymatic hydrolysis of cellulose in lignocellulosic feedstocks. The first part of our work combined compositional analysis, pretreatment and enzyme hydrolysis for fractionated pith, rind, and leaf tissues from a hybrid stay-green corn, in order to identify the role of structural characteristics on enzyme hydrolysis of cell walls. The extent of enzyme hydrolysis follows the sequence rind < leaves < pith with 90% conversion of cellulose to glucose in 24 h in the best cases. Physical fractionation of corn stalks or other C(4) grasses into soft and hard tissue types could reduce cost of cellulose conversion by enabling reduced enzyme loadings to hydrolyze soft tissue, and directing the hard tissue to other uses such as thermal processing, combustion, or recycle to the land from which the corn was harvested. Copyright © 2011 Wiley Periodicals, Inc.

  11. An efficient process for the saccharification of wood chips by combined ionic liquid pretreatment and enzymatic hydrolysis.

    PubMed

    Viell, Jörn; Wulfhorst, Helene; Schmidt, Thomas; Commandeur, Ulrich; Fischer, Rainer; Spiess, Antje; Marquardt, Wolfgang

    2013-10-01

    A process concept combining pretreatment of wood in ionic liquids and subsequent enzymatic hydrolysis to sugars is herein investigated to identify operating conditions which allow for (i) the processing of larger wood chips of 10 mm length, (ii) low temperature, (iii) high sugar yield, and (iv) short processing time. A careful quantitative study of the interaction of pretreatment and hydrolysis reveals that hydrolysis is most effective if beech chips are first disintegrated in [EMIM][Ac] at 115 °C for 1.5 h. The cellulose conversion varies between 70.5 wt% and 90.2wt% for hydrolysis times between 5 h and 72 h. A complete recovery of cellulose and xylan resulting in a total saccharification of 65 wt% of the wood chips could be demonstrated. It is shown that short pretreatment times are required to enable high sugar yield as well as to limit product degradation. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. In-depth investigation of enzymatic hydrolysis of biomass wastes based on three major components: Cellulose, hemicellulose and lignin.

    PubMed

    Lin, Lili; Yan, Rong; Liu, Yongqiang; Jiang, Wenju

    2010-11-01

    The artificial biomass based on three biomass components (cellulose, hemicellulose and lignin) were developed on the basis of a simplex-lattice approach. Together with a natural biomass sample, they were employed in enzymatic hydrolysis researches. Different enzyme combines of two commercial enzymes (ACCELLERASE 1500 and OPTIMASH BG) showed a potential to hydrolyze hemicellulose completely. Negligible interactions among the three components were observed, and the used enzyme ACCELLERASE 1500 was proven to be weak lignin-binding. On this basis, a multiple linear-regression equation was established for predicting the reducing sugar yield based on the component proportions in a biomass. The hemicellulose and cellulose in a biomass sample were found to have different contributions in staged hydrolysis at different time periods. Furthermore, the hydrolysis of rice straw was conducted to validate the computation approach through considerations of alkaline solution pretreatment and combined enzymes function, so as to understand better the nature of biomass hydrolysis, from the aspect of three biomass components.

  13. Pilot scale production of cellulolytic enzymes by Trichoderma reesei

    SciTech Connect

    Warzywoda, M.; Chevron, F.; Ferre, V.; Pourquie, J.

    1983-01-01

    The French substitute fuels program aims at the substitution of part of gasoline by methanol. In order to avoid phase separation of the gasoline-methanol blend, a cosolvant has to be added; one of the most efficient cosolvants is the mixture of acetone and butanol produced by anaerobic acetone-butanol fermentation. The Institut Francais du Petrole is thus implementing a research and development program on the production of acetone butanol from biomass, either sugar crops (fodder beets and Jerusalem artichoke) or lignocellulosic (corn stover and wheat straw). Production of sugars from lignocellulosics is a major part of this program. The enzymatic hydrolysis route, based on Trichoderma reesei cellulolytic enzymes, has been chosen since it does not cause any degradation of C/sub 5/ sugars which are good substrates of the acetone butanol fermentation. Efficient and cheap large-scale production of cellulolytic enzymes is thus a key step in this process. This paper reports on production of cellulases by Trichoderma reesei in a 3-m/sup 3/ pilot fermentor under conditions which should facilitate the scaling-up of the process. 7 references, 2 figures, 2 tables.

  14. Two major facilitator superfamily sugar transporters from Trichoderma reesei and their roles in induction of cellulase biosynthesis.

    PubMed

    Zhang, Weixin; Kou, Yanbo; Xu, Jintao; Cao, Yanli; Zhao, Guolei; Shao, Jing; Wang, Hai; Wang, Zhixing; Bao, Xiaoming; Chen, Guanjun; Liu, Weifeng

    2013-11-15

    Proper perception of the extracellular insoluble cellulose is key to initiating the rapid synthesis of cellulases by cellulolytic Trichoderma reesei. Uptake of soluble oligosaccharides derived from cellulose hydrolysis represents a potential point of control in the induced cascade. In this study, we identified a major facilitator superfamily sugar transporter Stp1 capable of transporting cellobiose by reconstructing a cellobiose assimilation system in Saccharomyces cerevisiae. The absence of Stp1 in T. reesei resulted in differential cellulolytic response to Avicel versus cellobiose. Transcriptional profiling revealed a different expression profile in the Δstp1 strain from that of wild-type strain in response to Avicel and demonstrated that Stp1 somehow repressed induction of the bulk of major cellulase and hemicellulose genes. Two other putative major facilitator superfamily sugar transporters were, however, up-regulated in the profiling. Deletion of one of them identified Crt1 that was required for growth and enzymatic activity on cellulose or lactose, but was not required for growth or hemicellulase activity on xylan. The essential role of Crt1 in cellulase induction did not seem to rely on its transporting activity because the overall uptake of cellobiose or sophorose by T. reesei was not compromised in the absence of Crt1. Phylogenetic analysis revealed that orthologs of Crt1 exist in the genomes of many filamentous ascomycete fungi capable of degrading cellulose. These data thus shed new light on the mechanism by which T. reesei senses and transmits the cellulose signal and offers potential strategies for strain improvement.

  15. Effect of the structural features of hydrochloric acid-deamidated wheat gluten on its susceptibility to enzymatic hydrolysis.

    PubMed

    Cui, Chun; Hu, Qingling; Ren, Jiaoyan; Zhao, Haifeng; You, Lijun; Zhao, Mouming

    2013-06-19

    The effect of the structural features of hydrochloric acid-deamidated wheat gluten with different degrees of deamidation (DDs) on the susceptibility to enzymatic hydrolysis by pancreatin was investigated. The wheat gluten deamidated by hydrochloric acid with a DD of 55% revealed the highest susceptibility to enzymatic hydrolysis as evaluated by the hydrolysis degree and nitrogen solubility index of the hydrolysates. An increase of peptides with MW below 3000 Da was observed as the DD increased. Raman spectra in the 1740-1800 cm⁻¹ and 521-530 cm⁻¹ range suggested that wheat gluten had taken off the deamidation with different DDs and that the disulfide bond had disrupted the sulfhydryl groups with different intensities, respectively. Results from the deconvolution of the amide I region of FTIR spectra in the 1600-1700 cm⁻¹ range showed that the content of the α-helix decreased and that the content of the β-turn and β-sheet increased with increasing DDs, which improved the molecular structure and flexibility of wheat gluten. A scanning electron microscope (SEM) revealed that the image of HDG-55% presented the smoothest surface and the least uniform pore, enabling the sample to be more susceptible to enzymatic hydrolysis. The above information will enable us to better understand the effect of structure on the susceptibility of deamidated wheat gluten.

  16. Enzymatic Hydrolysis and Ethanol Fermentation of High Dry Matter Wet-Exploded Wheat Straw at Low Enzyme Loading

    NASA Astrophysics Data System (ADS)

    Georgieva, Tania I.; Hou, Xiaoru; Hilstrøm, Troels; Ahring, Birgitte K.

    Wheat straw was pretreated by wet explosion using three different oxidizing agents (H2O2, O2, and air). The effect of the pretreatment was evaluated based on glucose and xylose liberated during enzymatic hydrolysis. The results showed that pretreatment with the use of O2 as oxidizing agent was the most efficient in enhancing overall convertibility of the raw material to sugars and minimizing generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15-20% will be necessary. However, high DM hydrolysis and fermentation are limited by high viscosity of the material, higher inhibition of the enzymes, and fermenting microorganism. The wet-explosion pretreatment method enabled relatively high yields from both enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) to be obtained when performed on unwashed slurry with 14% DM and a low enzyme loading of 10 FPU/g cellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicellulose conversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overall ethanol yield from SSF was 68%.

  17. Enzymatic hydrolysis and ethanol fermentation of high dry matter wet-exploded wheat straw at low enzyme loading.

    PubMed

    Georgieva, Tania I; Hou, Xiaoru; Hilstrøm, Troels; Ahring, Birgitte K

    2008-03-01

    Wheat straw was pretreated by wet explosion using three different oxidizing agents (H(2)O(2), O(2), and air). The effect of the pretreatment was evaluated based on glucose and xylose liberated during enzymatic hydrolysis. The results showed that pretreatment with the use of O(2) as oxidizing agent was the most efficient in enhancing overall convertibility of the raw material to sugars and minimizing generation of furfural as a by-product. For scale-up of the process, high dry matter (DM) concentrations of 15-20% will be necessary. However, high DM hydrolysis and fermentation are limited by high viscosity of the material, higher inhibition of the enzymes, and fermenting microorganism. The wet-explosion pretreatment method enabled relatively high yields from both enzymatic hydrolysis and simultaneous saccharification and fermentation (SSF) to be obtained when performed on unwashed slurry with 14% DM and a low enzyme loading of 10 FPU/g cellulose in an industrial acceptable time frame of 96 h. Cellulose and hemicellulose conversion from enzymatic hydrolysis were 70 and 68%, respectively, and an overall ethanol yield from SSF was 68%.

  18. Combination of biological pretreatment with mild acid pretreatment for enzymatic hydrolysis and ethanol production from water hyacinth.

    PubMed

    Ma, Fuying; Yang, Na; Xu, Chunyan; Yu, Hongbo; Wu, Jianguo; Zhang, Xiaoyu

    2010-12-01

    The mild acid pretreatment and the combination of biological pretreatment by a white rot fungus Echinodontium taxodii or a brown rot fungus Antrodia sp. 5898 with mild acid pretreatment were evaluated under different pretreatment conditions for enzymatic hydrolysis and ethanol production from water hyacinth. The combined pretreatment with E. taxodii (10 days) and 0.25% H(2)SO(4) was proved to be more effective than the sole acid pretreatment. The reducing sugar yield from enzymatic hydrolysis of co-treated water hyacinth increased 1.13-2.11 fold than that of acid-treated water hyacinth at the same conditions. The following study on separate hydrolysis and fermentation with Saccharomyces cerevisiae indicated that the ethanol yield from co-treated water hyacinth achieved 0.192 g/g of dry matter, which increased 1.34-fold than that from acid-treated water hyacinth (0.146 g/g of dry matter). This suggested that the combination of biological and mild acid pretreatment is a promising method to improve enzymatic hydrolysis and ethanol production from water hyacinth with low lignin content. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  19. Utilization of recombinant Trichoderma reesei expressing Aspergillus aculeatus β-glucosidase I (JN11) for a more economical production of ethanol from lignocellulosic biomass.

    PubMed

    Treebupachatsakul, Treesukon; Shioya, Koki; Nakazawa, Hikaru; Kawaguchi, Takashi; Morikawa, Yasushi; Shida, Yosuke; Ogasawara, Wataru; Okada, Hirofumi

    2015-12-01

    The capacity of Trichoderma reesei cellulase to degrade lignocellulosic biomass has been enhanced by the construction of a recombinant T. reesei strain expressing Aspergillus aculeatus β-glucosidase I. We have confirmed highly efficient ethanol production from converge-milled Japanese cedar by recombinant T. reesei expressing A. aculeatus β-glucosidase I (JN11). We investigated the ethanol productivity of JN11 and compared it with the cocktail enzyme T. reesei PC-3-7 with reinforced cellobiase activity by the commercial Novozyme 188. Results showed that the ethanol production efficiency under enzymatic hydrolysis of JN11 was comparable to the cocktail enzyme both on simultaneous saccharification and fermentation (SSF) or separate hydrolysis and fermentation (SHF) processes. Moreover, the cocktail enzyme required more protein loading for attaining similar levels of ethanol conversion as JN11. We propose that JN11 is an intrinsically economical enzyme that can eliminate the supplementation of BGL for PC-3-7, thereby reducing the cost of industrial ethanol production from lignocellulosic biomass.

  20. Characteristics and enzymatic hydrolysis of cellulose-rich fractions from steam exploded and sequentially alkali delignified bamboo (Phyllostachys pubescens).

    PubMed

    Sun, Shao-Ni; Cao, Xue-Fei; Zhang, Xue-Ming; Xu, Feng; Sun, Run-Cang; Jones, Gwynn Lloyd

    2014-07-01

    In this study, cellulose-rich fractions from bamboo were prepared with steam explosion pretreatment (SEP) followed by a successive alkaline delignification to improve the enzymatic digestibility for an efficient bioethanol production. The cellulose-rich fractions obtained were characterized by FT-IR, XRD, CP/MAS (13)C NMR, SEM, and BET surface area. It was found that the SEP alone significantly removed partial hemicelluloses, while the synergistic treatment by SEP and alkaline delignification removed most hemicelluloses and lignin. Results from enzymatic hydrolysis showed that SEP alone improved the enzymatic hydrolysis rate by 7.9-33.1%, while the synergistic treatment by SEP and alkaline delignification enhanced the rate by 45.7-63.9%. The synergistic treatment by SEP at 2.0 MPa for 5 min with water impregnation followed by a successive alkaline delignification with 0.5% NaOH and 70% ethanol containing 1.5% NaOH resulted in a maximum enzymatic hydrolysis rate of 70.6%.

  1. Addition of Surfactants and Non-Hydrolytic Proteins and Their Influence on Enzymatic Hydrolysis of Pretreated Sugarcane Bagasse.

    PubMed

    Méndez Arias, Johanna; de Oliveira Moraes, Anelize; Modesto, Luiz Felipe Amarante; de Castro, Aline Machado; Pereira, Nei

    2017-02-01

    Poly(ethylene glycol) (PEG 4000) and bovine serum albumin (BSA) were investigated with the purpose of evaluating their influence on enzymatic hydrolysis of sugarcane bagasse. Effects of these supplements were assayed for different enzymatic cocktails (Trichoderma harzianum and Penicillium funiculosum) that acted on lignocellulosic material submitted to different pretreatment methods with varying solid (25 and 100 g/L) and protein (7.5 and 20 mg/g cellulose) loadings. The highest levels of glucose release were achieved using partially delignified cellulignin as substrate, along with the T. harzianum cocktail: increases of 14 and 18 % for 25 g/L solid loadings and of 33 and 43 % for 100 g/L solid loadings were reached for BSA and PEG supplementation, respectively. Addition of these supplements could maintain hydrolysis yield even for higher solid loadings, but for higher enzymatic cocktail protein loadings, increases in glucose release were not observed. Results indicate that synergism might occur among these additives and cellulase and xylanases. The use of these supplements, besides depending on factors such as pretreatment method of sugarcane bagasse, enzymatic cocktails composition, and solid and protein loadings, may not always lead to positive effects on the hydrolysis of lignocellulosic material, making it necessary further statistical studies, according to process conditions.

  2. Enzymatic hydrolysis of poly(ethyleneterephthalate) used for and analysed by pore modification of track-etched membranes.

    PubMed

    Gamerith, Caroline; Gajda, Martyna; Ortner, Andreas; Acero, Enrique Herrero; Guebitz, Georg M; Ulbricht, Mathias

    2017-10-25

    The potential of limited enzymatic poly(ethylene terephthalate) (PET) surface hydrolysis for the modification of track-etched (TE) membranes was investigated. Cutinases 1 and 2 from Thermobifida cellulosilytica as well as a fusion protein of cutinase 1 with the polymer binding module from the polyhydroxyalkanoate depolymerase of Alcaligenes faecalis (Thc_Cut1_PBM) were shown to hydrolyse highly crystalline PET TE membranes with a pore diameter of ∼120nm at very narrow size distribution. Furthermore the effects of surface chemistry were investigated by comparison of enzymatic hydrolysis by Thc_Cut1_PBM of "as received" PET TE membranes with two surface functionalized versions towards a "hydrophilic" and a more "hydrophobic" surface. The effects of adsorbed protein and the efficacy of cleaning steps after enzymatic treatment were elucidated by complementary methods for surface analysis and membrane characterization. With the optimized cleaning protocol, all adsorbed protein could be removed from the enzyme-treated membranes and effects of chemical surface functionalization of the PET TE membranes were demonstrated. The highest efficiency of enzymatic surface hydrolysis was observed for the original PET TE membranes, leading to an 0.36% weight loss corresponding to a removal of ∼3nm PET from the entire surface of the porous membrane. This correlates very well with the measured increase of barrier pore diameter by 4nm (a radius reduction? of 2nm), leading to about a two-fold increased water permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Changes on structural properties of biomass pretreated by combined deacetylation with liquid hot water and its effect on enzymatic hydrolysis.

    PubMed

    Jiang, Wei; Chang, Senlin; Qu, Yongshui; Zhang, Zhiguo; Xu, Jian

    2016-11-01

    A novel combined pretreatment of deacetylation and liquid hot water (LHW) was invented which has been proved to be effective in increasing enzymatic hydrolysis yield of biomass. In order to further understand the effect of this new pretreatment process on biomass, the variation on structural properties including cellulose crystallinity index (CrI), specific surface area (SSA) and degree of polymerization (DP) before/after pretreatment and how these properties affected the enzymatic hydrolysis of biomass were explored. The improvement of pretreatment severity (PS) could increase CrI, SSA and reduce DP. Whereas the enhancement of degree of deacetylation could decrease SSA and DP. An optimal formula (E12Y=0.347(100-CrI)(-0.375)×(SSA)(0.203)×(1700-DP)(0.281)) was achieved to express the correlation between structural properties and enzymatic hydrolysis after 12h. The enzymatic yield was more sensitive to CrI than to SSA and DP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

    SciTech Connect

    Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; Cavalier, David; Da Costa Sousa, Leonardo; Dale, Bruce E.; Balan, Venkatesh

    2015-11-26

    Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production from cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

  5. Sugar loss and enzyme inhibition due to oligosaccharide accumulation during high solids-loading enzymatic hydrolysis

    DOE PAGES

    Xue, Saisi; Uppugundla, Nirmal; Bowman, Michael J.; ...

    2015-11-26

    Accumulation of recalcitrant oligosaccharides during high-solids loading enzymatic hydrolysis of cellulosic biomass reduces biofuel yields and increases processing costs for a cellulosic biorefinery. Recalcitrant oligosaccharides in AFEX-pretreated corn stover hydrolysate accumulate to the extent of about 18–25 % of the total soluble sugars in the hydrolysate and 12–18 % of the total polysaccharides in the inlet biomass (untreated), equivalent to a yield loss of about 7–9 kg of monomeric sugars per 100 kg of inlet dry biomass (untreated). These oligosaccharides represent a yield loss and also inhibit commercial hydrolytic enzymes, with both being serious bottlenecks for economical biofuel production frommore » cellulosic biomass. Very little is understood about the nature of these oligomers and why they are recalcitrant to commercial enzymes. This work presents a robust method for separating recalcitrant oligosaccharides from high solid loading hydrolysate in gramme quantities. Composition analysis, recalcitrance study and enzyme inhibition study were performed to understand their chemical nature. Results indicate that, oligosaccharide accumulation occurs during high solid loading enzymatic hydrolysis of corn stover (CS) irrespective of using different pretreated corn stover (dilute acid: DA, ionic liquids: IL, and ammonia fibre expansion: AFEX). The methodology for large-scale separation of recalcitrant oligosaccharides from 25 % solids-loading AFEXcorn stover hydrolysate using charcoal fractionation and size exclusion chromatography is reported for the first time. Oligosaccharides with higher degree of polymerization (DP) were recalcitrant towards commercial enzyme mixtures [Ctec2, Htec2 and Multifect pectinase (MP)] compared to lower DP oligosaccharides. Enzyme inhibition studies using processed substrates (Avicel and xylan) showed that low DP oligosaccharides also inhibit commercial enzymes. Addition of monomeric sugars to oligosaccharides increases the

  6. Combination of enzymatic hydrolysis and ethanol organosolv pretreatments: effect on lignin structures, delignification yields and cellulose-to-glucose conversion.

    PubMed

    Obama, Patrick; Ricochon, Guillaume; Muniglia, Lionel; Brosse, Nicolas

    2012-05-01

    Enzymatic pre-hydrolysis using the industrial enzymatic cocktail Cellulyve® was assessed as a first step in a pretreatment process of Miscanthus biomass involving an aqueous-ethanol organosolv treatment. (13)C and (31)P Nuclear Magnetic Resonance and size exclusion chromatography were used to analyze the cellulose and lignin before and after treatment. It was demonstrated that despite a very low impact on the fibre structure (observed by Scanning Electron Microscopy) and composition (in terms of sugars and polyphenolics content), the enzymatic pre-treatment disrupted the lignocellulosic matrix to a considerable extend. This weakening permitted enhanced removal of lignin during organosolv pulping and increased hydrolysability of the residual cellulosic pulp for the production of monomeric glucose. Using this combined treatment, a delignification yield of 93% and an enzymatic cellulose-to-glucose conversion of 75% were obtained.

  7. Enzymatic hydrolysis of gelatin layers on used lith film using thermostable alkaline protease for recovery of silver and PET film.

    PubMed

    Masui, Akihiko; Yasuda, Masahiro; Fujiwara, Nobuaki; Ishikawa, Haruo

    2004-01-01

    To develop a new efficient and potential industrial enzymatic process for the recovery of silver and poly(ethylene terephthalate) (PET) from used lith film for printing, which has not been recycled at all, enzymatic hydrolysis of gelatin layers on lith film was investigated using the thermostabilized mutant enzyme of the alkaline protease from alkaliphilic Bacillus sp. B21-2. The rate of gelatin hydrolysis of lith film in a stirred-tank reactor increased with the temperature and enzyme concentration. The time required to complete the hydrolysis of gelatin on lith film was longer than that on X-ray film because of the tightly cross-linked structure of the gelatin layers of lith film. The time required to complete the hydrolysis by using the mutant enzyme was less than that using the wild-type enzyme. The gelatin hydrolysis of lith film was well explained by a model that took into consideration a number of physical processes in addition to the chemical process.

  8. Pretreatment of wheat straw by nonionic surfactant-assisted dilute acid for enhancing enzymatic hydrolysis and ethanol production.

    PubMed

    Qi, Benkun; Chen, Xiangrong; Wan, Yinhua

    2010-07-01

    Pretreating wheat straw (WS) with combined use of varied sulfuric acid concentration (0-3%, w/v) and Tween 20 concentration (0-1%) was investigated in an attempt to enhance the hydrolysis and fermentability of pretreated WS. Enzymatic hydrolysis yield of glucan and xylan and ethanol production by simultaneous saccharification and fermentation (SSF) of water-insoluble solids (WIS) were significantly affected by the amount of Tween 20 added during acid pretreatment. Any further addition of Tween 20 in either hydrolysis stage or fermentation stage only led to small increase in glucan conversion and ethanol production. Determination of adsorption of cellulases during hydrolysis showed that Tween 20-assisted acid treated straw solution contained more free cellulases than individual acid treated straw solution, indicating that modification of lignin surface by Tween 20 added during pretreatment likely occurred. In addition, the effects of pretreatment conditions on overall recovery of glucose and xylose after pretreatment and enzymatic hydrolysis were also investigated. Copyright 2010 Elsevier Ltd. All rights reserved.

  9. Effect of mixing on enzymatic hydrolysis of steam-pretreated spruce: a quantitative analysis of conversion and power consumption.

    PubMed

    Palmqvist, Benny; Wiman, Magnus; Lidén, Gunnar

    2011-05-11

    When scaling up lignocellulose-based ethanol production, the desire to increase the final ethanol titer after fermentation can introduce problems. A high concentration of water-insoluble solids (WIS) is needed in the enzymatic hydrolysis step, resulting in increased viscosity, which can cause mass and heat transfer problems because of poor mixing of the material. In the present study, the effects of mixing on the enzymatic hydrolysis of steam-pretreated spruce were investigated using a stirred tank reactor operated with different impeller speeds and enzyme loadings. In addition, the results were related to the power input needed to operate the impeller at different speeds, taking into account the changes in rheology throughout the process. A marked difference in hydrolysis rate at different impeller speeds was found. For example, the conversion was twice as high after 48 hours at 500 rpm compared with 25 rpm. This difference remained throughout the 96 hours of hydrolysis. Substantial amounts of energy were required to achieve only minor increases in conversion during the later stages of the process. Impeller speed strongly affected both the hydrolysis rate of the pretreated spruce and needed power input. Similar conversions could be obtained at different energy input by altering the mixing (that is, energy input), enzyme load and residence time, an important issue to consider when designing large-scale plants.

  10. Tylosin detection in animal feed by liquid chromatography-tandem mass spectrometry with enzymatic hydrolysis of the tylosin urea adduct.

    PubMed

    Van Poucke, Christof; Dumoulin, Fréderic; De Keyser, Kirsten; Elliott, Chris; Van Peteghem, Carlos

    2004-05-19

    When the use of tylosin as a feed additive was forbidden by Council Regulation 2821/98, the necessity of a chemical confirmation method for the monitoring of the ban was created. Recently a method was developed for the detection of tylosin in animal feed by means of LC-MS/MS. During the validation high deviating values for the decision limit, detection capability, and repeatability for tylosin in cattle feed were observed, and the presence of urea and the formation of a tylosin urea adduct (TUA) were suggested as possible explanations. In this study two hydrolysis approaches for the TUA adduct were compared, namely, a chemical hydrolysis and an enzymatic hydrolysis with urease. The latter yielded a more complete hydrolysis of urea and was used for further validation. The recovery increased by approximately 15-25% depending on the amount of urea present in the feed (0.5-2%). The decision limit and detection capability were hardly influenced by the enzymatic hydrolysis.

  11. High-solid enzymatic hydrolysis and fermentation of solka floc into ethanol.

    PubMed

    Um, Byung-Hwan; Hanley, Thomas R

    2008-07-01

    To lower the cost of ethanol distillation of fermentation broths, a high initial glucose concentration is desired. However, an increase in the substrate concentration typically reduces the ethanol yield because of insufficient mass and heat transfer. In addition, different operating temperatures are required to optimize the enzymatic hydrolysis (50 degrees C) and fermentation (30 degrees C). Thus, to overcome these incompatible temperatures, saccharification followed by fermentation (SFF) was employed with relatively high solid concentrations (10% to 20%) using a portion loading method. In this study, glucose and ethanol were produced from Solka Floc, which was first digested by enzymes at 50 degrees for 48 h, followed by fermentation. In this process, commercial enzymes were used in combination with a recombinant strain of Zymomonas mobilis (39679:pZB4L). The effects of the substrate concentration (10% to 20%, w/v) and reactor configuration were also investigated. In the first step, the enzyme reaction was achieved using 20 FPU/g cellulose at 50 degrees C for 96 h. The fermentation was then performed at 30 degrees C for 96 h. The enzymatic digestibility was 50.7%, 38.4%, and 29.4% after 96 h with a baffled Rushton impeller and initial solid concentration of 10%, 15%, and 20% (w/v), respectively, which was significantly higher than that obtained with a baffled marine impeller. The highest ethanol yield of 83.6%, 73.4%, and 21.8%, based on the theoretical amount of glucose, was obtained with a substrate concentration of 10%, 15%, and 20%, respectively, which also corresponded to 80.5%, 68.6%, and 19.1%, based on the theoretical amount of the cell biomass and soluble glucose present after 48 h of SFF.

  12. Evaluation of soluble fraction and enzymatic residual fraction of dilute dry acid, ethylenediamine, and steam explosion pretreated corn stover on the enzymatic hydrolysis of cellulose.

    PubMed

    Qin, Lei; Liu, Li; Li, Wen-Chao; Zhu, Jia-Qing; Li, Bing-Zhi; Yuan, Ying-Jin

    2016-06-01

    This study is aimed to examine the inhibition of soluble fraction (SF) and enzymatic residual fraction (ERF) in dry dilute acid (DDA), ethylenediamine (EDA) and steam explosion (SE) pretreated corn stover (CS) on the enzymatic digestibility of cellulose. SF of DDA, EDA and SE pretreated CS has high xylose, soluble lignin and xylo-oligomer content, respectively. SF of EDA pretreated CS leads to the highest inhibition, followed by SE and DDA pretreated CS. Inhibition of ERF of DDA and SE pretreated CS is higher than that of EDA pretreated CS. The inhibition degree (A0/A) of SF is 1.76 and 1.21 times to that of ERF for EDA and SE pretreated CS, respectively. The inhibition degree of ERF is 1.05 times to that of SF in DDA pretreated CS. The quantitative analysis shows that SF of EDA pretreated CS, SF and ERF of SE pretreated CS cause significant inhibition during enzymatic hydrolysis.

  13. Hydrolysis of lignocelluloses by penicillium funiculosum cellulase

    SciTech Connect

    Mishra, C.; Rao, M.; Seeta, R.; Srinivasan, M.C.; Deshpande, V.

    1984-04-01

    Enzymatic hydrolysis of cellulose is a promising method for the conversion of waste cellulose to glucose. During the past few years, the development of this technology has proceeded rapidly, with significant advances made in enzyme production, pretreatment, and hydrolysis. A variety of fungi are reported to produce cellulases but among these Trichoderma reesei and its mutants are powerful producers of cellulases. However, the search for new and possibly better sources of cellulase is continued due to the low levels of beta-glucosidase of T. reesei. Penicillium funiculosum produces a complete cellulase having endo-beta-1,4-glucanase (15-20 U/mL), exo-beta-1,4-glucanase (1.5-2.0 U/mL), and high beta-glucosidase (8-10 U/mL). The saccharification of alkali-treated cotton and bagasse by P. funiculosum enzyme was 70 and 63%, respectively. It was possible to obtain glucose concentration as high as 30% using 50% bagasse. It is of interest that the percent saccharification of cellulosic substrates with the Penicillium enzyme is comparable to that of T. reesei cellulase when the same amount of filter paper activity is used, although the endo-glucanase activity of the latter is two to three times higher. This communication reports the studies on saccharification of lignocelluloses by P. funiculosum cellulase and certain studies on the kinetic aspects. (Refs. 15).

  14. Scale-up and evaluation of high solid ionic liquid pretreatment and enzymatic hydrolysis of switchgrass

    PubMed Central

    2013-01-01

    Background Ionic liquid (IL) pretreatment is receiving significant attention as a potential process that enables fractionation of lignocellulosic biomass and produces high yields of fermentable sugars suitable for the production of renewable fuels. However, successful optimization and scale up of IL pretreatment involves challenges, such as high solids loading, biomass handling and transfer, washing of pretreated solids and formation of inhibitors, which are not addressed during the development stages at the small scale in a laboratory environment. As a first in the research community, the Joint BioEnergy Institute, in collaboration with the Advanced Biofuels Process Demonstration Unit, a Department of Energy funded facility that supports academic and industrial entities in scaling their novel biofuels enabling technologies, have performed benchmark studies to identify key challenges associated with IL pretreatment using 1-ethyl-3-methylimidazolium acetate and subsequent enzymatic saccharification beyond bench scale. Results Using switchgrass as the model feedstock, we have successfully executed 600-fold, relative to the bench scale (6 L vs 0.01 L), scale-up of IL pretreatment at 15% (w/w) biomass loading. Results show that IL pretreatment at 15% biomass generates a product containing 87.5% of glucan, 42.6% of xylan and only 22.8% of lignin relative to the starting material. The pretreated biomass is efficiently converted into monosaccharides during subsequent enzymatic hydrolysis at 10% loading over a 150-fold scale of operations (1.5 L vs 0.01 L) with 99.8% fermentable sugar conversion. The yield of glucose and xylose in the liquid streams were 94.8% and 62.2%, respectively, and the hydrolysate generated contains high titers of fermentable sugars (62.1 g/L of glucose and 5.4 g/L cellobiose). The overall glucan and xylan balance from pretreatment and saccharification were 95.0% and 77.1%, respectively. Enzymatic inhibition by [C2mim][OAc] at high solids

  15. Rheology and gel point of the enzymatic hydrolysis of urea in the presence of urease

    NASA Astrophysics Data System (ADS)

    Serrato-Millán, R.; Medina-Torres, L.; Calderas, F.; España-Sánchez, B. L.; Estevez, M.; Hernandez-Martínez, A. R.; Cruz-Soto, M.; Sánchez, I. C.; Gómez-García, R.; Sánchez-Betancourt, I.; Velasquillo-Martínez, M. C.; Luna-Bárcenas, G.

    2017-02-01

    This study reports on the rheology of the gelation kinetics of raw chitosan (CTS) solutions (2% w/v) produced by enzymatic hydrolysis of urea at different urea concentrations (40, 50, 60, 80, and 100 mM) in the presence of urease at 1 U/mL. Viscoelastic parameters and pH values were evaluated during gelation process and the rheological properties of CTS hydrogels produced were monitored after 24 h at 37°C to simulate human body temperatures. pH measurements suggest that above some critical urea concentration (50 mM) the time required ( t gel ) to reach the critical pH gelation shows no dependence on urea concentration ( t gel was ca. 70 minutes). Above 50 mM of urea concentration, CTS hydrogels exhibit an elastic modulus G' higher than the viscous modulus G″ with no frequency dependence characteristic of a gel behavior. Gelation kinetics analyzed by rheology suggest that the G' ( i.e., structure) development depends on urea concentration during solution neutralization.

  16. Bioconversion of Welan Gum from Kitchen Waste by a Two-Step Enzymatic Hydrolysis Pretreatment.

    PubMed

    Li, Panyu; Xie, Yi; Zeng, Yu; Hu, Wanrong; Kang, Yan; Li, Xiang; Wang, Yabo; Xie, Tonghui; Zhang, Yongkui

    2017-04-01

    Kitchen waste (KW) is a worldwide issue, which can lead to environment pollution. Nevertheless, it is also a low-cost and sustainable resource for bio-production. Meanwhile, welan gum (WG) is one kind of the most important exopolysaccharide but with high material cost. The aim of this study was to adopt two-step enzymatic hydrolysis to improve the release and recovery of both sugar and protein in KW for subsequent WG production. As the results, the recovery rates of sugar and protein reached 81.07 and 77.38%, which were both satisfactory. After the conditions optimized in flasks, the welan fermentation was conducted in a 5-L fermentor, and the WG yield, utilization rates of reducing sugar and KDN, respectively, reached 5.57 g L(-1), 94.25% and 61.96%. Moreover, the kinetic analyses demonstrated that the WG fermentation in KWH was a partly growth-associated process. The KW was successfully treated by fermentation for the bioconversion to WG.

  17. A novel non-hydrolytic protein from Pseudomonas oryzihabitans enhances the enzymatic hydrolysis of cellulose.

    PubMed

    Qin, Yi-Min; Tao, Heng; Liu, You-Yan; Wang, Yan-Dong; Zhang, Jing-Ru; Tang, Ai-Xing

    2013-10-10

    Several kinds of protein such as the expansin, expansin-like proteins and LPMOs (lytic polysaccharide monooxygenases) are known to exert enhancement effects on cellulase activity. In this study, a novel cellulase synergistic protein named POEP1 was purified from the culture filtrate of Pseudomonas oryzihabitans CGMCC 6169, and was homogeneous on SDS-PAGE with a molecular weight of 60kDa. Mass spectrometry analysis indicated that it was an unknown protein without sequence similarity to the expansin and expansin-like proteins. Evaluation of the enzymatic hydrolysis of filter paper revealed that POEP1 had no cellulase activity but displayed high synergistic activity of 364% at a cellulase concentration of 0.1FPU/g of filter paper. When a mixture containing 0.6FPU cellulase and 700μg POEP1 per g of cellulose was evaluated, the maximal sugar yield was achieved, which was 2.2-fold greater than that with the cellulase alone. POEP1 was found to have functional similarity to the expansin and expansin-like proteins, which could decrease both the hydrogen-bond intensity and crystallinity, and cause the filter paper disruption. This study provided evidence for the existence of novel bacterial proteins in nature serving the same function as expansin and expansin-like proteins.

  18. Production of bio-ethanol from pretreated agricultural byproduct using enzymatic hydrolysis and simultaneous saccharification.

    PubMed

    Gomathi, D; Muthulakshmi, C; Kumar, D Guru; Ravikumar, G; Kalaiselvi, M; Uma, C

    2012-01-01

    Global warming alerts and threats are on the rise due to the utilization of fossil fuels. Alternative fuel sources like bio-ethanol and biodiesel are being produced to combat against these threats. Bio-ethanol can be produced from a range of substrate. The present study is aimed at the Production of bioethanol from pretreated agricultural substrate using enzymatic hydrolysis and simultaneous saccharification with the addition of purified fungal enzyme. Most cellulosic biomass is not fermentable without appropriate pretreatment methods and so dilute sulfuric acid pretreatment was applied to make the cellulose contained in the waste susceptible to endoglucanase enzyme. A range of acid pretreatment of wheat bran was made in which the sample that was pretreated with 1% dilute sulfuric acid gave maximum yield of ethanol in both methods such as 5.83 g L(-1) and 5.27 g L(-1), respectively. Ethanol produced from renewable and cheap agricultural products (wheat bran) provides reduction in green house gas emission, carbon monoxide, sulfur, and helps to eliminate smog from the environment.

  19. Enzymatic Hydrolysis of Alginate to Produce Oligosaccharides by a New Purified Endo-Type Alginate Lyase

    PubMed Central

    Zhu, Benwei; Chen, Meijuan; Yin, Heng; Du, Yuguang; Ning, Limin

    2016-01-01

    Enzymatic hydrolysis of sodium alginate to produce alginate oligosaccharides has drawn increasing attention due to its advantages of containing a wild reaction condition, excellent gel properties and specific products easy for purification. However, the efficient commercial enzyme tools are rarely available. A new alginate lyase with high activity (24,038 U/mg) has been purified from a newly isolated marine strain, Cellulophaga sp. NJ-1. The enzyme was most active at 50 °C and pH 8.0 and maintained stability at a broad pH range (6.0–10.0) and temperature below 40 °C. It had broad substrate specificity toward sodium alginate, heteropolymeric MG blocks (polyMG), homopolymeric M blocks (polyM) and homopolymeric G blocks (polyG), and possessed higher affinity toward polyG (15.63 mM) as well as polyMG (23.90 mM) than polyM (53.61 mM) and sodium alginate (27.21 mM). The TLC and MS spectroscopy analysis of degradation products suggested that it completely hydrolyzed sodium alginate into oligosaccharides of low degrees of polymerization (DPs). The excellent properties would make it a promising tool for full use of sodium alginate to produce oligosaccharides. PMID:27275826

  20. Tobacco alkaloids reduction by casings added/enzymatic hydrolysis treatments assessed through PLSR analysis.

    PubMed

    Lin, Shunshun; Zhang, Xiaoming; Song, Shiqing; Hayat, Khizar; Eric, Karangwa; Majeed, Hamid

    2016-03-01

    Based on encouraged development of potential reduced-exposure products (PREPs) by the US Institute of Medicine, casings (glucose and peptides) added treatments (CAT) and enzymatic (protease and xylanase) hydrolysis treatments (EHT) were developed to study their effect on alkaloids reduction in tobacco and cigarette mainstream smoke (MS) and further investigate the correlation between sensory attributes and alkaloids. Results showed that the developed treatments reduced nicotine by 14.5% and 24.4% in tobacco and cigarette MS, respectively, indicating that both CAT and EHT are potentially effective for developing lower-risk cigarettes. Sensory and electronic nose analysis confirmed the significant influence of treatments on sensory and cigarette MS components. PLSR analysis demonstrated that tobacco alkaloids were positively correlated to the off-taste, irritation and impact attributes, and negatively correlated to the aroma and softness attributes. Additionally, nicotine and anabasine from tobacco leaves positively contributed to the impact attribute, while they negatively contributed to the aroma attribute (P<0.05). Meanwhile, most alkaloids in cigarette MS positively contributed to the impact and irritation attributes (P<0.05). Hence, this study paved a way to better understand the correlation between tobacco alkaloids and sensory attributes.

  1. Substrate Dependency and Effect of Xylanase Supplementation on Enzymatic Hydrolysis of Ammonia-Treated Biomass

    NASA Astrophysics Data System (ADS)

    Gupta, Rajesh; Kim, Tae Hyun; Lee, Yoon Y.

    Pretreatment based on aqueous ammonia was investigated under two different modes of operation: soaking in aqueous ammonia and ammonia recycle percolation. These processes were applied to three different feedstocks with varied composition: corn stover, high lignin (HL), and low lignin (LL) hybrid poplars. One of the important features of ammonia-based pretreatment is that most of the hemicellulose is retained after treatment, which simplifies the overall bioconversion process and enhances the conversion efficiency. The pretreatment processes were optimized for these feedstocks, taking carbohydrate retention as well as sugar yield in consideration. The data indicate that hybrid poplar is more difficult to treat than corn stover, thus, requires more severe conditions. On the other hand, hybrid poplar has a beneficial property that it retains most of the hemicellulose after pretreatment. To enhance the digestibility of ammonia-treated poplars, xylanase was supplemented during enzymatic hydrolysis. Because of high retention of hemicellulose in treated hybrid poplar, xylanase supplementation significantly improved xylan as well as glucan digestibility. Of the three feedstocks, best results and highest improvement by xylanase addition was observed with LL hybrid poplar, showing 90% of overall sugar yield.

  2. Efficient enzymatic degradation process for hydrolysis activity of the Carrageenan from red algae in marine biomass.

    PubMed

    Kang, Dae Hee; Hyeon, Jeong Eun; You, Seung Kyou; Kim, Seung Wook; Han, Sung Ok

    2014-12-20

    Carrageenan is a generic name for a family of polysaccharides obtained from certain species of red algae. New methods to produce useful cost-efficiently materials from red algae are needed to convert enzymatic processes into fermentable sugars. In this study, we constructed chimeric genes cCgkA and cCglA containing the catalytic domain of κ-carrageenase CgkA and λ-carrageenase CglA from Pseudoalteromonas carrageenovora fused with a dockerin domain. Recombinant strains expressing the chimeric carrageenase resulted in a halo formation on the carrageenan plate by alcian blue staining. The recombinant cCgkA and cCglA were assembled with scaffoldin miniCbpA via cohesin and dockerin interaction. Carbohydrate binding module (CBM) in scaffoldin was used as a tag for cellulose affinity purification using cellulose as a support. The hydrolysis process was monitored by the amount of reducing sugar released from carrageenan. Interestingly, these results indicated that miniCbpA, cCgkA and cCglA assembled into a complex and that the dockerin-fused enzymes on the scaffoldin had synergistic activity in the degradation of carrageenan. The observed enhancement of activity by carrageenolytic complex was 3.1-fold-higher compared with the corresponding enzymes alone. Thus, the assemblies of advancement of active enzyme complexes will facilitate the commercial production of useful products from red algae biomass which represents inexpensive and sustainable feed-stocks.

  3. Behaviors and mechanism of acid dyes sorption onto diethylenetriamine-modified native and enzymatic hydrolysis starch.

    PubMed

    Wang, Zuohua; Xiang, Bo; Cheng, Rumei; Li, Yijiu

    2010-11-15

    In this paper, different starches were modified by diethylenetriamine. The native starch reacted with diethylenetriamine giving CAS, whereas the enzymatic hydrolysis starch was modified by diethylenetriamine producing CAES. Adsorption capacities of CAES for four acid dyes, namely, Acid orange 7 (AO7), Acid orange 10 (AO10), Acid green 25 (AG25) and Acid red 18 (AR18) have been determined to be 2.521, 1.242, 1.798 and 1.570 mmol g(-1), respectively. In all cases, CAES has exhibited higher sorption ability than CAS, and the increment for these dyes took the sequence of AO7 (0.944 mmol g(-1))>AO10 (0.592 mmol g(-1))>AR18 (0.411 mmol g(-1))>AG25 (0.047 mmol g(-1)). Sorption kinetics and isotherms analysis showed that these sorption processes were better fitted to pseudo-second-order equation and Langmuir equation. Chemical sorption mechanisms were confirmed by studying the effects of pH, ionic strength and hydrogen bonding. Thermodynamic parameters of these dyes onto CAES and CAS were also observed and it indicated that these sorption processes were exothermic and spontaneous in nature.

  4. Enhancing the enzymatic hydrolysis of corn stover by an integrated wet-milling and alkali pretreatment.

    PubMed

    He, Xun; Miao, Yelian; Jiang, Xuejian; Xu, Zidong; Ouyang, Pingkai

    2010-04-01

    An integrated wet-milling and alkali pretreatment was applied to corn stover prior to enzymatic hydrolysis. The effects of NaOH concentration in the pretreatment on crystalline structure, chemical composition, and reducing-sugar yield of corn stover were investigated, and the mechanism of increasing reducing-sugar yield by the pretreatment was discussed. The experimental results showed that the crystalline structure of corn stover was disrupted, and lignin was removed, while cellulose and hemicellulose were retained in corn stover by the pretreatment with 1% NaOH in 1 h. The reducing-sugar yield from the pretreated corn stovers increased from 20.2% to 46.7% when the NaOH concentration increased from 0% to 1%. The 1% NaOH pretreated corn stover had a holocellulose conversion of 55.1%. The increase in reducing-sugar yield was related to the crystalline structure disruption and delignification of corn stover. It was clarified that the pretreatment significantly enhanced the conversion of cellulose and hemicellulose in the corn stover to sugars.

  5. Responses of biomass briquetting and pelleting to water-involved pretreatments and subsequent enzymatic hydrolysis.

    PubMed

    Li, Yang; Li, Xiaotong; Shen, Fei; Wang, Zhanghong; Yang, Gang; Lin, Lili; Zhang, Yanzong; Zeng, Yongmei; Deng, Shihuai

    2014-01-01

    Although lignocellulosic biomass has been extensively regarded as the most important resource for bioethanol, the wide application was seriously restricted by the high transportation cost of biomass. Currently, biomass densification is regarded as an acceptable solution to this issue. Herein, briquettes, pellets and their corresponding undensified biomass were pretreated by diluted-NaOH and hydrothermal method to investigate the responses of biomass densification to these typical water-involved pretreatments and subsequent enzymatic hydrolysis. The densified biomass auto-swelling was initially investigated before pretreatment. Results indicated pellets could be totally auto-swollen in an hour, while it took about 24 h for briquettes. When diluted-NaOH pretreatment was performed, biomass briquetting and pelleting improved sugar conversion rate by 20.1% and 5.5% comparing with their corresponding undensified biomass. Pelleting improved sugar conversion rate by 7.0% after hydrothermal pretreatment comparing with the undensified biomass. However, briquetting disturbed hydrothermal pretreatment resulting in the decrease of sugar conversion rate by 15.0%.

  6. Enzymatic Hydrolysis of Alginate to Produce Oligosaccharides by a New Purified Endo-Type Alginate Lyase.

    PubMed

    Zhu, Benwei; Chen, Meijuan; Yin, Heng; Du, Yuguang; Ning, Limin

    2016-06-06

    Enzymatic hydrolysis of sodium alginate to produce alginate oligosaccharides has drawn increasing attention due to its advantages of containing a wild reaction condition, excellent gel properties and specific products easy for purification. However, the efficient commercial enzyme tools are rarely available. A new alginate lyase with high activity (24,038 U/mg) has been purified from a newly isolated marine strain, Cellulophaga sp. NJ-1. The enzyme was most active at 50 °C and pH 8.0 and maintained stability at a broad pH range (6.0-10.0) and temperature below 40 °C. It had broad substrate specificity toward sodium alginate, heteropolymeric MG blocks (polyMG), homopolymeric M blocks (polyM) and homopolymeric G blocks (polyG), and possessed higher affinity toward polyG (15.63 mM) as well as polyMG (23.90 mM) than polyM (53.61 mM) and sodium alginate (27.21 mM). The TLC and MS spectroscopy analysis of degradation products suggested that it completely hydrolyzed sodium alginate into oligosaccharides of low degrees of polymerization (DPs). The excellent properties would make it a promising tool for full use of sodium alginate to produce oligosaccharides.

  7. Effect of anatomical fractionation on the enzymatic hydrolysis of acid and alkaline pretreated corn stover.

    PubMed

    Duguid, K B; Montross, M D; Radtke, C W; Crofcheck, C L; Wendt, L M; Shearer, S A

    2009-11-01

    Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect for conversion. An ideal feedstock would require a low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis. Corn stover fractions were separated manually and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The stover fractions were also pretreated with either 0%, 0.4%, or 0.8% NaOH for 2 h at room temperature, washed, autoclaved and saccharified. In addition, dilute sulfuric acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF were 65% (standard error of 15.9%) for husks and 29% (standard error of 1.8%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.

  8. EFFECT OF ANATOMICAL FRACTIONATION ON THE ENZYMATIC HYDROLYSIS OF ACID AND ALKALINE PRETREATED CORN STOVER

    SciTech Connect

    K. B. Duguid; M. D. Montross; C. W. Radtke; C. L. Crofcheck; L. M. Wendt; S. A. Shearer

    2009-11-01

    Due to concerns with biomass collection systems and soil sustainability there are opportunities to investigate the optimal plant fractions to collect for conversion. An ideal feedstock would require low severity pretreatment to release a maximum amount of sugar during enzymatic hydrolysis. Corn stover fractions were separated by hand and analyzed for glucan, xylan, acid soluble lignin, acid insoluble lignin, and ash composition. The stover fractions were also pretreated with either 0, 0.4, or 0.8% NaOH for 2 hours at room temperature, washed, autoclaved and saccharified. In addition, acid pretreated samples underwent simultaneous saccharification and fermentation (SSF) to ethanol. In general, the two pretreatments produced similar trends with cobs, husks, and leaves responding best to the pretreatments, the tops of stalks responding slightly less, and the bottom of the stalks responding the least. For example, corn husks pretreated with 0.8% NaOH released over 90% (standard error of 3.8%) of the available glucan, while only 45% (standard error of 1.1%) of the glucan was produced from identically treated stalk bottoms. Estimates of the theoretical ethanol yield using acid pretreatment followed by SSF were 65% (standard error of 15.9%) for husks and 29% (standard error of 1.8%) for stalk bottoms. This suggests that integration of biomass collection systems to remove sustainable feedstocks could be integrated with the processes within a biorefinery to minimize overall ethanol production costs.

  9. Enzymatic hydrolysis and production of bioethanol from common macrophytic green alga Ulva fasciata Delile.

    PubMed

    Trivedi, Nitin; Gupta, Vishal; Reddy, C R K; Jha, Bhavanath

    2013-12-01

    The green seaweed Ulva which proliferates fast and occurs abundantly worldwide was used as a feedstock for production of ethanol following enzymatic hydrolysis. Among the different cellulases investigated for efficient saccharification, cellulase 22119 showed the highest conversion efficiency of biomass into reducing sugars than Viscozyme L, Cellulase 22086 and 22128. Pre-heat treatment of biomass in aqueous medium at 120°C for 1h followed by incubation in 2% (v/v) enzyme for 36 h at 45°C gave a maximum yield of sugar 206.82±14.96 mg/g. The fermentation of hydrolysate gave ethanol yield of 0.45 g/g reducing sugar accounting for 88.2% conversion efficiency. These values are substantially higher than those of reported so far for both agarophytes and carrageenophytes. It was also confirmed that enzyme can be used twice without compromising on the saccharification efficiency. The findings of this study reveal that Ulva can be a potential feedstock for bioethanol production. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Enhancing the hydrolysis and methane production potential of mixed food waste by an effective enzymatic pretreatment.

    PubMed

    Kiran, Esra Uçkun; Trzcinski, Antoine P; Liu, Yu

    2015-05-01

    In this study, a fungal mash rich in hydrolytic enzymes was produced by solid state fermentation (SSF) of waste cake in a simple and efficient manner and was further applied for high-efficiency hydrolysis of mixed food wastes (FW). The enzymatic pretreatment of FW with this fungal mash resulted in 89.1 g/L glucose, 2.4 g/L free amino nitrogen, 165 g/L soluble chemical oxygen demand (SCOD) and 64% reduction in volatile solids within 24h. The biomethane yield and production rate from FW pretreated with the fungal mash were found to be respectively about 2.3 and 3.5-times higher than without pretreatment. After anaerobic digestion of pretreated FW, a volatile solids removal of 80.4±3.5% was achieved. The pretreatment of mixed FW with the fungal mash produced in this study is a promising option for enhancing anaerobic digestion of FW in terms of energy recovery and volume reduction. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Effects of grain species and cultivar, thermal processing, and enzymatic hydrolysis on gluten quantitation.

    PubMed

    Pahlavan, Autusa; Sharma, Girdhari M; Pereira, Marion; Williams, Kristina M

    2016-10-01

    Gluten from wheat, rye, and barley can trigger IgE-mediated allergy or Celiac disease in sensitive individuals. Gluten-free labeled foods are available as a safe alternative. Immunoassays such as the enzyme-linked immunosorbent assay (ELISA) are commonly used to quantify gluten in foods. However, various non-assay related factors can affect gluten quantitation. The effect of gluten-containing grain cultivars, thermal processing, and enzymatic hydrolysis on gluten quantitation by various ELISA kits was evaluated. The ELISA kits exhibited variations in gluten quantitation depending on the gluten-containing grain and their cultivars. Acceptable gluten recoveries were obtained in 200mg/kg wheat, rye, and barley-spiked corn flour thermally processed at various conditions. However, depending on the enzyme, gluten grain source, and ELISA kit used, measured gluten content was significantly reduced in corn flour spiked with 200mg/kg hydrolyzed wheat, rye, and barley flour. Thus, the gluten grain source and processing conditions should be considered for accurate gluten analysis.

  12. Impact of regeneration process on the crystalline structure and enzymatic hydrolysis of cellulose obtained from ionic liquid.

    PubMed

    Cao, Xuefei; Peng, Xinwen; Sun, Shaoni; Zhong, Linxin; Wang, Sha; Lu, Fachuang; Sun, Runcang

    2014-10-13

    The present study investigated the impact of regeneration process on the crystalline structure and enzymatic hydrolysis behaviors of microcrystalline cellulose (MCC) regenerated from ionic liquid 1-butyl-3-methylimidazolium chloride. The crystalline structures of these regenerated samples were analyzed by X-ray diffraction. Results suggested that almost amorphous cellulose was obtained by regenerating MCC in acetone (DRC-a), while partial cellulose II structure could be found in these regenerated samples from water and ethanol. Additionally, the enzymatic hydrolysis behaviors of MCC and its regenerated samples were comparatively studied. Results showed that above 90% of cellulose could be converted into glucose within 4h for DRC-a and regenerated cellulose without drying (WRC-w) as compared to that of MCC (9.7%). Therefore, the regeneration process could significantly influence the crystallinity and digestibility of cellulose.

  13. Reconstitution of cellulose and lignin after [C2mim][OAc] pretreatment and its relation to enzymatic hydrolysis.

    PubMed

    Yuan, Tong-Qi; Wang, Wei; Zhang, Li-Ming; Xu, Feng; Sun, Run-Cang

    2013-03-01

    Although the effects of cellulose crystallinity and lignin content as two major structural features on enzymatic hydrolysis have been extensively studied, debates regarding their effects still exist. In this study, reconstitution of cellulose and lignin after 1-ethyl-3-methylimidazolium acetate ([C(2)mim][OAc]) pretreatment was proposed as a new method to study their effects on enzymatic digestibility. Different mechanisms of lignin content for reduction of cellulose hydrolysis were found between the proposed method and the traditional method (mixing of cellulose and lignin). The results indicated that a slight change of the crystallinity of the reconstituted materials may play a minor role in the change of enzyme efficiency. In addition, the present study suggested that the lignin content does not significantly affect the digestibility of cellulose, whereas the conversion of cellulose fibers from the cellulose I to the cellulose II crystal phase plays an important role when an ionic liquid pretreatment of biomass was conducted.

  14. Potential of phosphoric acid-catalyzed pretreatment and subsequent enzymatic hydrolysis for biosugar production from Gracilaria verrucosa.

    PubMed

    Kwon, Oh-Min; Kim, Sung-Koo; Jeong, Gwi-Taek

    2016-07-01

    This study combined phosphoric acid-catalyzed pretreatment and enzymatic hydrolysis to produce biosugars from Gracilaria verrucosa as a potential renewable resource for bioenergy applications. We optimized phosphoric acid-catalyzed pretreatment conditions to 1:10 solid-to-liquid ratio, 1.5 % phosphoric acid, 140 °C, and 60 min reaction time, producing a 32.52 ± 0.06 % total reducing sugar (TRS) yield. By subsequent enzymatic hydrolysis, a 68.61 ± 0.90 % TRS yield was achieved. These results demonstrate the potential of phosphoric acid to produce biosugars for biofuel and biochemical production applications.

  15. Hydrothermal treatment followed by enzymatic hydrolysis and hydrothermal carbonization as means to valorise agro- and forest-based biomass residues.

    PubMed

    Wikberg, Hanne; Grönqvist, Stina; Niemi, Piritta; Mikkelson, Atte; Siika-Aho, Matti; Kanerva, Heimo; Käsper, Andres; Tamminen, Tarja

    2017-07-01

    The suitability of several abundant but underutilized agro and forest based biomass residues for hydrothermal treatment followed by enzymatic hydrolysis as well as for hydrothermal carbonization was studied. The selected approaches represent simple biotechnical and thermochemical treatment routes suitable for wet biomass. Based on the results, the hydrothermal pre-treatment followed by enzymatic hydrolysis seemed to be most suitable for processing of carbohydrate rich corn leaves, corn stover, wheat straw and willow. High content of thermally stable components (i.e. lignin) and low content of ash in the biomass were advantageous for hydrothermal carbonization of grape pomace, coffee cake, Scots pine bark and willow. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The promoting effects of manganese on biological pretreatment with Irpex lacteus and enzymatic hydrolysis of corn stover.

    PubMed

    Song, Lili; Ma, Fuying; Zeng, Yelin; Zhang, Xiaoyu; Yu, Hongbo

    2013-05-01

    The effect of metal ions on biological pretreatment was evaluated for improving subsequent enzymatic hydrolysis. Results showed that the efficiency of fungal pretreatment was greatly improved with manganese supplement in biomass. After enzymatic hydrolysis of 28-d pretreated corn stover, maximum glucose yield was 308.98 mg/g corn stover with manganese supplement, which increased by 61.39% as compared to the conventional fungal pretreatment. Furthermore, manganese also enhanced the production of ethanol, corresponding to a high ethanol conversion (83.39%). Manganese greatly improved the delignification of Irpex lacteus specially. Correspondingly, the efficiency of saccharification and fermentation was closely related to the removal of lignin. This study showed a promising effect of manganese on fungal pretreatment and the production of biofuels.

  17. High selective delignification using oxidative ionic liquid pretreatment at mild conditions for efficient enzymatic hydrolysis of lignocellulose.

    PubMed

    Pang, Zhiqiang; Lyu, Wenkang; Dong, Cuihua; Li, Hongxing; Yang, Guihua

    2016-08-01

    Herein, the oxidative ionic liquid (IL) pretreatment for overcoming recalcitrance of lignocellulose with selective delignification was investigated, and the subsequent enzymatic hydrolysis was evaluated. IL pretreatment incorporating oxygen delignification could enhance lignin extraction with high selectivity at low carbohydrate loss. The dual-action of oxidative decomposition and dissolution by 1-butyl-3-methlimidazolium chloride (BmimCl) on biomass were synergistically acted, accounting for efficient recalcitrance removal. In addition, the mild oxidative IL treatment only slightly converted crystalline cellulose into amorphous structure, and the extensive extraction of the amorphous lignin and carbohydrate resulted to the expose of cellulose with high susceptibility. Correspondingly, the enzymatic hydrolysis of the pretreated lignocellulose was greatly enhanced. The oxidative IL treatment at mild conditions, collaborating BmimCl treatment with oxygen delignification is a promising and effective system for overcoming the robust structure of lignocellulose.

  18. Structural features of dilute acid, steam exploded, and alkali pretreated mustard stalk and their impact on enzymatic hydrolysis.

    PubMed

    Kapoor, Manali; Raj, Tirath; Vijayaraj, M; Chopra, Anju; Gupta, Ravi P; Tuli, Deepak K; Kumar, Ravindra

    2015-06-25

    To overcome the recalcitrant nature of biomass several pretreatment methodologies have been explored to make it amenable to enzymatic hydrolysis. These methodologies alter cell wall structure primarily by removing/altering hemicelluloses and lignin. In this work, alkali, dilute acid, steam explosion pretreatment are systematically studied for mustard stalk. To assess the structural variability after pretreatment, chemical analysis, surface area, crystallinity index, accessibility of cellulose, FT-IR and thermal analysis are conducted. Although the extent of enzymatic hydrolysis varies upon the methodologies used, nevertheless, cellulose conversion increases from <10% to 81% after pretreatment. Glucose yield at 2 and 72h are well correlated with surface area and maximum adsorption capacity. However, no such relationship is observed for xylose yield. Mass balance of the process is also studied. Dilute acid pretreatment is the best methodology in terms of maximum sugar yield at lower enzyme loading.

  19. Influence of enzyme loading on enzymatic hydrolysis of cardboard waste and size distribution of the resulting fiber residue.

    PubMed

    Kinnarinen, Teemu; Häkkinen, Antti

    2014-05-01

    Enzymatic hydrolysis of lignocellulosic biomass to sugars alters the properties of the cellulosic fibers. Several process variables, including enzyme loading, play an important role in these changes. Many physical properties of fibers are affected: their length and width, porosity, specific surface area, and degree of fibrillation, for instance, may undergo dramatic changes when subjected to enzymatic degradation. In this study, the influence of enzyme loading on the fiber size was investigated using milled cardboard waste as the raw material. The effect of cellulases and hemicellulases on the monosaccharide production and the resulting fiber size was studied using commercial enzyme products. It was shown that the cellulase loading largely determined the amount of sugars produced. The fiber length was reduced during the course of hydrolysis, although the size reduction was not especially dramatic. Based on the SEM images, no significant damage to the fiber surfaces occurred during the process.

  20. Production of Recombinant Trichoderma reesei Cellobiohydrolase II in a New Expression System Based on Wickerhamomyces anomalus

    PubMed Central

    Díaz-Rincón, Dennis J.; Duque, Ivonne; Osorio, Erika; Rodríguez-López, Alexander; Espejo-Mojica, Angela; Parra-Giraldo, Claudia M.

    2017-01-01

    Cellulase is a family of at least three groups of enzymes that participate in the sequential hydrolysis of cellulose. Recombinant expression of cellulases might allow reducing their production times and increasing the low proteins concentrations obtained with filamentous fungi. In this study, we describe the production of Trichoderma reesei cellobiohydrolase II (CBHII) in a native strain of Wickerhamomyces anomalus. Recombinant CBHII was expressed in W. anomalus 54-A reaching enzyme activity values of up to 14.5 U L−1. The enzyme extract showed optimum pH and temperature of 5.0–6.0 and 40°C, respectively. Enzyme kinetic parameters (KM of 2.73 mM and Vmax of 23.1 µM min−1) were between the ranges of values reported for other CBHII enzymes. Finally, the results showed that an enzymatic extract of W. anomalus 54-A carrying the recombinant T. reesei CBHII allows production of reducing sugars similar to that of a crude extract from cellulolytic fungi. These results show the first report on the use of W. anomalus as a host to produce recombinant proteins. In addition, recombinant T. reesei CBHII enzyme could potentially be used in the degradation of lignocellulosic residues to produce bioethanol, based on its pH and temperature activity profile. PMID:28951785

  1. Production of Recombinant Trichoderma reesei Cellobiohydrolase II in a New Expression System Based on Wickerhamomyces anomalus.

    PubMed

    Díaz-Rincón, Dennis J; Duque, Ivonne; Osorio, Erika; Rodríguez-López, Alexander; Espejo-Mojica, Angela; Parra-Giraldo, Claudia M; Poutou-Piñales, Raúl A; Alméciga-Díaz, Carlos J; Quevedo-Hidalgo, Balkys

    2017-01-01

    Cellulase is a family of at least three groups of enzymes that participate in the sequential hydrolysis of cellulose. Recombinant expression of cellulases might allow reducing their production times and increasing the low proteins concentrations obtained with filamentous fungi. In this study, we describe the production of Trichoderma reesei cellobiohydrolase II (CBHII) in a native strain of Wickerhamomyces anomalus. Recombinant CBHII was expressed in W. anomalus 54-A reaching enzyme activity values of up to 14.5 U L(-1). The enzyme extract showed optimum pH and temperature of 5.0-6.0 and 40°C, respectively. Enzyme kinetic parameters (KM of 2.73 mM and Vmax of 23.1 µM min(-1)) were between the ranges of values reported for other CBHII enzymes. Finally, the results showed that an enzymatic extract of W. anomalus 54-A carrying the recombinant T. reesei CBHII allows production of reducing sugars similar to that of a crude extract from cellulolytic fungi. These results show the first report on the use of W. anomalus as a host to produce recombinant proteins. In addition, recombinant T. reesei CBHII enzyme could potentially be used in the degradation of lignocellulosic residues to produce bioethanol, based on its pH and temperature activity profile.

  2. Temperature induced decoupling of enzymatic hydrolysis and carbon remineralization in long-term incubations of Arctic and temperate sediments

    NASA Astrophysics Data System (ADS)

    Robador, Alberto; Brüchert, Volker; Steen, Andrew D.; Arnosti, Carol

    2010-04-01

    Extracellular enzymatic hydrolysis of high-molecular weight organic matter is the initial step in sedimentary organic carbon degradation and is often regarded as the rate-limiting step. Temperature effects on enzyme activities may therefore exert an indirect control on carbon mineralization. We explored the temperature sensitivity of enzymatic hydrolysis and its connection to subsequent steps in anoxic organic carbon degradation in long-term incubations of sediments from the Arctic and the North Sea. These sediments were incubated under anaerobic conditions for 24 months at temperatures of 0, 10, and 20 °C. The short-term temperature response of the active microbial community was tested in temperature gradient block incubations. The temperature optimum of extracellular enzymatic hydrolysis, as measured with a polysaccharide (chondroitin sulfate), differed between Arctic and temperate habitats by about 8-13 °C in fresh sediments and in sediments incubated for 24 months. In both Arctic and temperate sediments, the temperature response of chondroitin sulfate hydrolysis was initially similar to that of sulfate reduction. After 24 months, however, hydrolysis outpaced sulfate reduction rates, as demonstrated by increased concentrations of dissolved organic carbon (DOC) and total dissolved carbohydrates. This effect was stronger at higher incubation temperatures, particularly in the Arctic sediments. In all experiments, concentrations of volatile fatty acids (VFA) were low, indicating tight coupling between VFA production and consumption. Together, these data indicate that long-term incubation at elevated temperatures led to increased decoupling of hydrolytic DOC production relative to fermentation. Temperature increases in marine sedimentary environments may thus significantly affect the downstream carbon mineralization and lead to the increased formation of refractory DOC.

  3. Investigation of the pellets produced from sugarcane bagasse during liquid hot water pretreatment and their impact on the enzymatic hydrolysis.

    PubMed

    Wang, Wen; Zhuang, Xinshu; Yuan, Zhenhong; Yu, Qiang; Qi, Wei

    2015-08-01

    In 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. They were composed of 81.0% lignin, 7.0% glucan, and 3.2% xylan. The LHW pretreatment solution (PS) was sprayed to the filter paper, and the pellets were observed on its surface. Fourier transform infrared spectroscopy (FTIR) data showed that lignin was also the main component of the PS pellets. The effect of the pellets on enzymatic hydrolysis was chiefly attributed to the steric hindrance, not the cellulase adsorption. The structural characteristics of LHW-treated SCB might play a more important role in influencing the enzymatic hydrolysis than the pellets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Effects of thermo-chemical pretreatment plus microbial fermentation and enzymatic hydrolysis on saccharification and lignocellulose degradation of corn straw.

    PubMed

    Wang, Ping; Chang, Juan; Yin, Qingqiang; Wang, Erzhu; Zhu, Qun; Song, Andong; Lu, Fushan

    2015-10-01

    In order to increase corn straw degradation, the straw was kept in the combined solution of 15% (w/w) lime supernatant and 2% (w/w) sodium hydroxide with liquid-to-solid ratio of 13:1 (mL/g) at 83.92°C for 6h; and then added with 3% (v/v) H2O2 for reaction at 50°C for 2h; finally cellulase (32.3 FPU/g dry matter) and xylanase (550 U/g dry matter) was added to keep at 50°C for 48 h. The maximal reducing sugars yield (348.77 mg/g) was increased by 126.42% (P<0.05), and the degradation rates of cellulose, hemicellulose and lignin in pretreated corn straw with enzymatic hydrolysis were increased by 40.08%, 45.71% and 52.01%, compared with the native corn straw with enzymatic hydrolysis (P<0.05). The following study indicated that the combined microbial fermentation and enzymatic hydrolysis could further increase straw degradation and reducing sugar yield (442.85 mg/g, P<0.05).

  5. Recycling cellulases by pH-triggered adsorption-desorption during the enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Shang, Yaping; Su, Rongxin; Huang, Renliang; Yang, Yang; Qi, Wei; Li, Qiujin; He, Zhimin

    2014-06-01

    Recycling of cellulases is an effective way to reduce the cost of enzymatic hydrolysis for the production of cellulosic ethanol. In this study, we examined the adsorption and desorption behaviors of cellulase at different pH values and temperatures. Furthermore, we developed a promising way to recover both free and bound cellulases by pH-triggered adsorption-desorption. The results show that acidic pH (e.g., pH 4.8) was found to favor adsorption, whereas alkaline pH (e.g., pH 10) and low temperature (4-37 °C) favored desorption. The adsorption of cellulases reached an equilibrium within 60 min at pH 4.8 and 25 °C, leading to approximately 50 % of the added cellulases bound to the substrate. By controlling the pH of eluent (citrate buffer, 25 °C), we were able to increase the desorption efficiency of bound cellulases from 15 % at pH 4.8 to 85 % at pH 10. To recover cellulases after enzymatic hydrolysis, we employed adsorption by fresh substrate and desorption at pH 10 to recover the free cellulases in supernatant and the bound cellulases in residue, respectively. The recycling performance (based on the glucose yield) of this simple strategy could reach near 80 %. Our results provided a simple, low-cost, and effective approach for cellulase recycling during the enzymatic hydrolysis of lignocellulosic biomass.

  6. Effect of anion structures on cholinium ionic liquids pretreatment of rice straw and the subsequent enzymatic hydrolysis.

    PubMed

    Hou, Xue-Dan; Xu, Jie; Li, Ning; Zong, Min-Hua

    2015-01-01

    In this work, 28 cholinium ionic liquids (ILs), most of which are good solvents for dissolving lignin, were used for rice straw pretreatment to improve subsequent enzymatic hydrolysis. The anion exerted a significant effect on the pretreatment effectiveness of the IL as well as the subsequent enzymatic hydrolysis efficiency of rice straw residues. The presence of the basic group(s) in the anion significantly enhanced the IL pretreatment effectiveness, while the carboxyl, hydroxyl and aromatic groups had a negative impact on IL delignification. Except for amino acid-based ILs, the delignification abilities of the ILs are linearly and positively correlated with the pKa values of the conjugate acids of the anions. Of the ILs tested, amino acid-based ILs, especially basic amino acid-based ILs, are the most effective pretreatment solvents. Satisfactory reducing sugar yields (81% for glucose and 26% for xylose) were obtained in the enzymatic hydrolysis of rice straw pretreated by cholinium argininate ([Ch][Arg]) under a pretty mild pretreatment severity (60°C, 6 h). The results presented in this work may be useful for rational design of novel and green ILs for delignification of lignocellulose.

  7. Sequential Fenton oxidation and hydrothermal treatment to improve the effect of pretreatment and enzymatic hydrolysis on mixed hardwood.

    PubMed

    Jeong, So-Yeon; Lee, Jae-Won

    2016-01-01

    Sequential Fenton oxidation (FO) and hydrothermal treatment were performed to improve the effect of pretreatment and enzymatic hydrolysis of mixed hardwood. The molar ratio of the Fenton reagent (FeSO4·7H2O and H2O2) was 1:25, and the reaction time was 96h. During the reaction, little or no weight loss of biomass was observed. The concentration of Fe(2+) was determined and was found to increase continuously during FO. Hydrothermal treatment at 190-210°C for 10-80min was performed following FO. Sequential FO and hydrothermal treatment showed positive effects on pretreatment and enzymatic hydrolysis. Xylose concentration in the hydrolysate was as high as 14.16g/L when FO-treated biomass was treated at 190°C, while its concentration in the raw material was 3.72g/L. After 96h of enzymatic hydrolysis, cellulose conversion in the biomass obtained following sequential treatment was 69.58-79.54%. In contrast, the conversion in the raw material (without FO) was 64.41-67.92%.

  8. Statistical optimization of recycled-paper enzymatic hydrolysis for simultaneous saccharification and fermentation via central composite design.

    PubMed

    Liu, Qing; Cheng, Ke-ke; Zhang, Jian-an; Li, Jin-ping; Wang, Ge-hua

    2010-01-01

    A central composite design of the response surface methodology (RSM) was employed to study the effects of temperature, enzyme concentration, and stirring rate on recycled-paper enzymatic hydrolysis. Among the three variables, temperature and enzyme concentration significantly affected the conversion efficiency of substrate, whereas stirring rate was not effective. A quadratic polynomial equation was obtained for enzymatic hydrolysis by multiple regression analysis using RSM. The results of validation experiments were coincident with the predicted model. The optimum conditions for enzymatic hydrolysis were temperature, enzyme concentration, and stirring rate of 43.1 degrees C, 20 FPU g(-1) substrate, and 145 rpm, respectively. In the subsequent simultaneous saccharification and fermentation (SSF) experiment under the optimum conditions, the highest 28.7 g ethanol l(-1) was reached in the fed-batch SSF when 5% (w/v) substrate concentration was used initially, and another 5% added after 12 h fermentation. This ethanol output corresponded to 77.7% of the theoretical yield based on the glucose content in the raw material.

  9. Recovery of Whey Proteins and Enzymatic Hydrolysis of Lactose Derived from Casein Whey Using a Tangential Flow Ultrafiltration Module

    NASA Astrophysics Data System (ADS)

    Das, Bipasha; Bhattacharjee, Sangita; Bhattacharjee, Chiranjib

    2013-09-01

    In this study, ultrafiltration (UF) of pretreated casein whey was carried out in a cross-flow module fitted with 5 kDa molecular weight cut-off polyethersulfone membrane to recover whey proteins in the retentate and lactose in the permeate. Effects of processing conditions, like transmembrane pressure and pH on permeate flux and rejection were investigated and reported. The polarised layer resistance was found to increase with time during UF even in this high shear device. The lactose concentration in the permeate was measured using dinitro salicylic acid method. Enzymatic kinetic study for lactose hydrolysis was carried out at three different temperatures ranging from 30 to 50 °C using β-galactosidase enzyme. The glucose formed during lactose hydrolysis was analyzed using glucose oxidase-peroxidase method. Kinetics of enzymatic hydrolysis of lactose solution was found to follow Michaelis-Menten model and the model parameters were estimated by Lineweaver-Burk plot. The hydrolysis rate was found to be maximum (with Vmax = 5.5091 mmol/L/min) at 30 °C.

  10. Isolation and purification of arctigenin from Fructus Arctii by enzymatic hydrolysis combined with high-speed counter-current chromatography.

    PubMed

    Liu, Feng; Xi, Xingjun; Wang, Mei; Fan, Li; Geng, Yanling; Wang, Xiao

    2014-02-01

    Enzymatic hydrolysis pretreatment combined with high-speed counter-current chromatography for the transformation and isolation of arctigenin from Fructus Arctii was successfully developed. In the first step, the extract solution of Fructus Arctii was enzymatic hydrolyzed by β-glucosidase. The optimal hydrolysis conditions were 40°C, pH 5.0, 24 h of hydrolysis time, and 1.25 mg/mL β-glucosidase concentration. Under these conditions, the content of arctigenin was transformed from 2.60 to 12.59 mg/g. In the second step, arctigenin in the hydrolysis products was separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (10:25:15:20, v/v), and the fraction was analyzed by HPLC, ESI-MS, and (1)H NMR spectroscopy. Finally, 102 mg of arctigenin with a purity of 98.9% was obtained in a one-step separation from 200 mg of hydrolyzed sample. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. The pretreatment of corn stover with Gloeophyllum trabeum KU-41 for enzymatic hydrolysis

    PubMed Central

    2012-01-01

    Background Pretreatment is an essential step in the enzymatic hydrolysis of biomass for bio-ethanol production. The dominant concern in this step is how to decrease the high cost of pretreatment while achieving a high sugar yield. Fungal pretreatment of biomass was previously reported to be effective, with the advantage of having a low energy requirement and requiring no application of additional chemicals. In this work, Gloeophyllum trabeum KU-41 was chosen for corn stover pretreatment through screening with 40 strains of wood-rot fungi. The objective of the current work is to find out which characteristics of corn stover pretreated with G. trabeum KU-41 determine the pretreatment method to be successful and worthwhile to apply. This will be done by determining the lignin content, structural carbohydrate, cellulose crystallinity, initial adsorption capacity of cellulase and specific surface area of pretreated corn stover. Results The content of xylan in pretreated corn stover was decreased by 43% in comparison to the untreated corn stover. The initial cellulase adsorption capacity and the specific surface area of corn stover pretreated with G. trabeum were increased by 7.0- and 2.5-fold, respectively. Also there was little increase in the cellulose crystallinity of pretreated corn stover. Conclusion G. trabeum has an efficient degradation system, and the results indicated that the conversion of cellulose to glucose increases as the accessibility of cellulose increases due to the partial removal of xylan and the structure breakage of the cell wall. This pretreatment method can be further explored as an alternative to the thermochemical pretreatment method. PMID:22559172

  12. Enzymatic Hydrolysis of Trilactone Siderophores: Where Chiral Recognition Occurs in Enterobactin and Bacillibactin Iron Transport1

    PubMed Central

    Abergel, Rebecca J.; Zawadzka, Anna M.; Hoette, Trisha M.; Raymond, Kenneth N.

    2009-01-01

    Bacillibactin and enterobactin are hexadentate catecholate siderophores produced by bacteria upon iron limitation to scavenge ferric ion and seem to be the ultimate siderophores of their two respective domains: Gram-positive and Gram-negative. Iron acquisition mediated by these trilactone-based ligands necessitates enzymatic hydrolysis of the scaffold for successful intracellular iron delivery. The esterases BesA and Fes hydrolyze bacillibactin and enterobactin, respectively, as well as the corresponding iron complexes. Bacillibactin binds iron through three 2,3-catecholamide moieties linked to a tri-threonine scaffold via glycine spacers, whereas in enterobactin the iron-binding moieties are directly attached to a tri-l-serine backbone; although apparently minor, these structural differences result in markedly different iron coordination properties and iron transport behavior. Comparison of the solution thermodynamic and circular dichroism properties of bacillibactin, enterobactin and the synthetic analogs d-enterobactin, SERGlyCAM and d-SERGlyCAM has determined the role of each different feature in the siderophores' molecular structures in ferric complex stability and metal chirality. While opposite metal chiralities in the different complexes did not affect transport and incorporation in Bacillus subtilis, ferric complexes formed with the various siderophores did not systematically promote growth of the bacteria. The bacillibactin esterase BesA is less specific than the enterobactin esterase Fes; BesA can hydrolyze the trilactones of both siderophores, while only the tri-l-serine trilactone is a substrate of Fes. Both enzymes are stereospecific and cannot cleave tri-d-serine lactones. These data provide a complete picture of the microbial iron transport mediated by these two siderophores, from initial recognition and transport to intracellular iron release. PMID:19673474

  13. Alkaline-assisted screw press pretreatment affecting enzymatic hydrolysis of wheat straw.

    PubMed

    Yan, Qingqi; Wang, Yumei; Rodiahwati, Wawat; Spiess, Antje; Modigell, Michael

    2017-02-01

    Screw press processing of biomass can be considered as a suitable mechanically based pretreatment for biofuel production since it disrupts the structure of lignocellulosic biomass with high shear and pressure forces. The combination with chemical treatment has been suggested to increase the conversion of lignocellulosic biomass to fermentable sugars. Within the study, the synergetic effect of alkaline (sodium hydroxide, NaOH) soaking and screw press pretreatment on wheat straw was evaluated based on, e.g., sugar recovery and energy efficiency. After alkaline soaking (at 0.1 M for 30 min) and sequential screw press pretreatment with various screw press configurations and modified screw barrel, the lignin content of pretreated wheat straw was quantified. In addition, the structure of pretreated wheat straw was investigated by scanning electron microscopy and measurement of specific surface area. It could be shown that removal of lignin is more important than increase of surface area of the biomass to reach a high sugar recovery. The rate constant of the enzymatic hydrolysis increased from 1.1 × 10(-3) 1/h for the non-treated material over 2.3 × 10(-3) 1/h for the alkaline-soaked material to 26.9 × 10(-3) 1/h for alkaline-assisted screw press pretreated material, indicating a nearly 25-fold improvement of the digestibility by the combined chemo-mechanical pretreatment. Finally, the screw configuration was found to be an important factor for improving the sugar recovery and for reducing the specific energy consumption of the screw press pretreatment.

  14. The pretreatment of corn stover with Gloeophyllum trabeum KU-41 for enzymatic hydrolysis.

    PubMed

    Gao, Ziqing; Mori, Toshio; Kondo, Ryuichiro

    2012-05-04

    Pretreatment is an essential step in the enzymatic hydrolysis of biomass for bio-ethanol production. The dominant concern in this step is how to decrease the high cost of pretreatment while achieving a high sugar yield. Fungal pretreatment of biomass was previously reported to be effective, with the advantage of having a low energy requirement and requiring no application of additional chemicals. In this work, Gloeophyllum trabeum KU-41 was chosen for corn stover pretreatment through screening with 40 strains of wood-rot fungi. The objective of the current work is to find out which characteristics of corn stover pretreated with G. trabeum KU-41 determine the pretreatment method to be successful and worthwhile to apply. This will be done by determining the lignin content, structural carbohydrate, cellulose crystallinity, initial adsorption capacity of cellulase and specific surface area of pretreated corn stover. The content of xylan in pretreated corn stover was decreased by 43% in comparison to the untreated corn stover. The initial cellulase adsorption capacity and the specific surface area of corn stover pretreated with G. trabeum were increased by 7.0- and 2.5-fold, respectively. Also there was little increase in the cellulose crystallinity of pretreated corn stover. G. trabeum has an efficient degradation system, and the results indicated that the conversion of cellulose to glucose increases as the accessibility of cellulose increases due to the partial removal of xylan and the structure breakage of the cell wall. This pretreatment method can be further explored as an alternative to the thermochemical pretreatment method.

  15. Enzymatic hydrolysis of trilactone siderophores: where chiral recognition occurs in enterobactin and bacillibactin iron transport.

    PubMed

    Abergel, Rebecca J; Zawadzka, Anna M; Hoette, Trisha M; Raymond, Kenneth N

    2009-09-09

    Bacillibactin and enterobactin are hexadentate catecholate siderophores produced by bacteria upon iron limitation to scavenge ferric ion and seem to be the ultimate siderophores of their two respective domains: Gram-positive and Gram-negative. Iron acquisition mediated by these trilactone-based ligands necessitates enzymatic hydrolysis of the scaffold for successful intracellular iron delivery. The esterases BesA and Fes hydrolyze bacillibactin and enterobactin, respectively, as well as the corresponding iron complexes. Bacillibactin binds iron through three 2,3-catecholamide moieties linked to a trithreonine scaffold via glycine spacers, whereas in enterobactin the iron-binding moieties are directly attached to a tri-l-serine backbone; although apparently minor, these structural differences result in markedly different iron coordination properties and iron transport behavior. Comparison of the solution thermodynamic and circular dichroism properties of bacillibactin, enterobactin and the synthetic analogs d-enterobactin, SERGlyCAM and d-SERGlyCAM has determined the role of each different feature in the siderophores' molecular structures in ferric complex stability and metal chirality. While opposite metal chiralities in the different complexes did not affect transport and incorporation in Bacillus subtilis, ferric complexes formed with the various siderophores did not systematically promote growth of the bacteria. The bacillibactin esterase BesA is less specific than the enterobactin esterase Fes; BesA can hydrolyze the trilactones of both siderophores, while only the tri-l-serine trilactone is a substrate of Fes. Both enzymes are stereospecific and cannot cleave tri-d-serine lactones. These data provide a complete picture of the microbial iron transport mediated by these two siderophores, from initial recognition and transport to intracellular iron release.

  16. Limitations of the NNS assay for reducing sugars from saccharified lignocellulosics. [Trichoderma reesei

    SciTech Connect

    Rivers, D.B.; Gracheck, S.J.; Woodford, L.C.; Emert, G.H.

    1984-07-01

    An evaluation is presented of two DNS (2,4-dinitrosalicylic acid) assay procedures as well as high-performance liquid chromatography (HPLC) and YSI Glucose Analyzer analyses of sugars resulting from enzymatic saccharification of lignocellulosics. Trichoderma reesei was used to produce the cellulase system containing endoglucanase, cellobiohydrolase and cellobiase. Data suggest that the DNS assay can be used as an accurate analytical method for the evaluation of reducing sugars in pure solution as well as in supernatants from enzymatic saccharification if glucose is the sole product. However, only specific assay methods such as HPLC and YSI-type glucose analyzers should be used for the analysis of saccharides produced from the hydrolysis of native or pretreated lignocellulosics since the DNS assay is susceptible to interferences and therefore results in inaccurate analyses.

  17. Enzymatic hydrolysis of various pretreated lignocellulosic substrates and the fermentation of the liberated sugars to ethanol and butanediol

    SciTech Connect

    Saddler, J.N.; Mes-Hartree, M.; Yu, E.K.C.; Brownell, H.H.

    1983-01-01

    Aspen wood and wheat straw were pretreated by exposure to steam at elevated temperatures. Chemical analysis of the substrates revealed that steam explosion differentially decomposed the pentosan component while leaving the glucan portion relatively unchanged. The pretreated residues could be used as substrates for growth of Trichoderma reesei C30 and T. harzianum E58. The cellulase activities detected were in some cases three times as high as those found when Solka Floc was used as the substrate. Culture filtrates of T. harzianum E58 could efficiently hydrolyze the hemicellulose-rich water-soluble fractions. This material was fermented by Klebsiella pneumoniae with 0.4-0.5 g of 2,3-butanediol produced per gram of sugar utilized. Once the steam-exploded residues had been water and alkali extracted, the enzymatically hydrolyzed substrates were readily fermented by Saccharomyces cerevisiae or Zymononas mobilis with values as high as 2% (w/v) ethanol obtained from 5% steam-exploded wood fractions. 30 references, 2 figures, 8 tables.

  18. Alkaline-sulfite pretreatment and use of surfactants during enzymatic hydrolysis to enhance ethanol production from sugarcane bagasse.

    PubMed

    Mesquita, Jéssica Faria; Ferraz, André; Aguiar, André

    2016-03-01

    Sugarcane bagasse is a by-product from the sugar and ethanol industry which contains approximately 70 % of its dry mass composed by polysaccharides. To convert these polysaccharides into fuel ethanol it is necessary a pretreatment step to increase the enzymatic digestibility of the recalcitrant raw material. In this work, sugarcane bagasse was pretreated by an alkaline-sulfite chemithermomechanical process for increasing its enzymatic digestibility. Na2SO3 and NaOH ratios were fixed at 2:1, and three increasing chemical loads, varying from 4 to 8 % m/m Na2SO3, were used to prepare the pretreated materials. The increase in the alkaline-sulfite load decreased the lignin content in the pretreated material up to 35.5 % at the highest chemical load. The pretreated samples presented enhanced glucose yields during enzymatic hydrolysis as a function of the pretreatment severity. The maximum glucose yield (64 %) was observed for the samples pretreated with the highest chemical load. The use of 2.5 g l(-1) Tween 20 in the hydrolysis step further increased the glucose yield to 75 %. Semi-simultaneous hydrolysis and fermentation of the pretreated materials indicated that the ethanol yield was also enhanced as a function of the pretreatment severity. The maximum ethanol yield was 56 ± 2 % for the sample pretreated with the highest chemical load. For the sample pretreated with the lowest chemical load (2 % m/m NaOH and 4 % m/m Na2SO3), adding Tween 20 during the hydrolysis process increased the ethanol yield from 25 ± 3 to 39.5 ± 1 %.

  19. A comparison of the autohydrolysis and ammonia fiber explosion (AFEX) pretreatments on the subsequent enzymatic hydrolysis of coastal Bermuda grass.

    PubMed

    Lee, Jung Myoung; Jameel, Hasan; Venditti, Richard A

    2010-07-01

    Two distinct pretreatment technologies, autohydrolysis and AFEX, have been applied to coastal Bermuda grass (CBG) followed by enzymatic hydrolysis in order to compare the effects of pretreatment on the subsequent sugar generation. Furthermore, the influence of structural features from each pretreatment on biomass digestibility was characterized with SEM, ATR-FTIR, and XRD. Enzymatic conversion of pretreated solids from the pretreatments increased with elevated temperature and longer residence times. AFEX pretreatment at 100 degrees C for 30 min produced a sugar yield of 94.8% of theoretical possible with 30 FPU/g enzymatic loading, the maximum achieved with AFEX. It was also shown that with autohydrolysis at 170 degrees C for 60 min that 55.4% sugar yield of the theoretical possible was produced with a 30 FPU/g enzymatic loading, the maximum with autohydrolysis. AFEX pretreatment does not change the chemical composition of CBG but autohydrolysis reduces hemicellulose content in the pretreated solids. Both pretreatments cause re-localization of lignin components. There was no observed correlation between crystallinity and enzyme digestibility of the pretreated solids. AFEX pretreatment developed more enzymatic accessibility to pretreated solids of CBG than did autohydrolysis pretreatment, leading to more sugar generation through the whole process. The total amount of sugars accounted for with autohydrolysis decreases with increasing temperature, consistent with increased byproduct generation via thermal degradation reactions. Published by Elsevier Ltd.

  20. The roles of xylan and lignin in oxalic acid pretreated corncob during separate enzymatic hydrolysis and ethanol fermentation.

    PubMed

    Lee, Jae-Won; Rodrigues, Rita C L B; Kim, Hyun Joo; Choi, In-Gyu; Jeffries, Thomas W

    2010-06-01

    High yields of hemicellulosic and cellulosic sugars are critical in obtaining economical conversion of agricultural residues to ethanol. To optimize pretreatment conditions, we evaluated oxalic acid loading rates, treatment temperatures and times in a 2(3) full factorial design. Response-surface analysis revealed an optimal oxalic acid pretreatment condition to release sugar from the cob of Zea mays L. ssp. and for Pichia stipitis CBS 6054. To ferment the residual cellulosic sugars to ethanol following enzymatic hydrolysis, highest saccharification and fermentation yields were obtained following pretreatment at 180 degrees C for 50 min with 0.024 g oxalic acid/g substrate. Under these conditions, only 7.5% hemicellulose remained in the pretreated substrate. The rate of cellulose degradation was significantly less than that of hemicellulose and its hydrolysis was not as extensive. Subsequent enzymatic saccharification of the residual cellulose was strongly affected by the pretreatment condition with cellulose hydrolysis ranging between 26.0% and 76.2%. The residual xylan/lignin ratio ranged from 0.31 to 1.85 depending on the pretreatment condition. Fermentable sugar and ethanol were maximal at the lowest ratio of xylan/lignin and at high glucan contents. The model predicts optimal condition of oxalic acid pretreatment at 168 degrees C, 74 min and 0.027 g/g of oxalic acid. From these findings, we surmised that low residual xylan was critical in obtaining maximal glucose yields from saccharification.

  1. Overexpression of an exotic thermotolerant β-glucosidase in trichoderma reesei and its significant increase in cellulolytic activity and saccharification of barley straw

    PubMed Central

    2012-01-01

    Background Trichoderma reesei is a widely used industrial strain for cellulase production, but its low yield of β-glucosidase has prevented its industrial value. In the hydrolysis process of cellulolytic residues by T. reesei, a disaccharide known as cellobiose is produced and accumulates, which inhibits further cellulases production. This problem can be solved by adding β-glucosidase, which hydrolyzes cellobiose to glucose for fermentation. It is, therefore, of high vvalue to construct T. reesei strains which can produce sufficient β-glucosidase and other hydrolytic enzymes, especially when those enzymes are capable of tolerating extreme conditions such as high temperature and acidic or alkali pH. Results We successfully engineered a thermostable β-glucosidase gene from the fungus Periconia sp. into the genome of T. reesei QM9414 strain. The engineered T. reesei strain showed about 10.5-fold (23.9 IU/mg) higher β-glucosidase activity compared to the parent strain (2.2 IU/mg) after 24 h of incubation. The transformants also showed very high total cellulase activity (about 39.0 FPU/mg) at 24 h of incubation whereas the parent strain almost did not show any total cellulase activity at 24 h of incubation. The recombinant β-glucosidase showed to be thermotolerant and remains fully active after two-hour incubation at temperatures as high as 60°C. Additionally, it showed to be active at a wide pH range and maintains about 88% of its maximal activity after four-hour incubation at 25°C in a pH range from 3.0 to 9.0. Enzymatic hydrolysis assay using untreated, NaOH, or Organosolv pretreated barley straw as well as microcrystalline cellulose showed that the transformed T. reesei strains released more reducing sugars compared to the parental strain. Conclusions The recombinant T. reesei overexpressing Periconia sp. β-glucosidase in this study showed higher β-glucosidase and total cellulase activities within a shorter incubation time (24 h) as well as

  2. Reducing non-productive adsorption of cellulase and enhancing enzymatic hydrolysis of lignocelluloses by noncovalent modification of lignin with lignosulfonate.

    PubMed

    Lou, Hongming; Wang, Mengxia; Lai, Huanran; Lin, Xuliang; Zhou, Mingsong; Yang, Dongjie; Qiu, Xueqing

    2013-10-01

    Four fractions of one commercial sodium lignosulfonate (SXP) with different molecular weight (MW) and anionic polymers were studied to reduce non-productive adsorption of cellulase on bound lignin in a lignocellulosic substrate. SXP with higher MW had stronger blocking effect on non-productive adsorption of a commercial Trichoderma reesi cellulase cocktail (CTec2) on lignin measured by quartz crystal microgravimetry with dissipation monitoring. Linear anionic aromatic polymers have strong blocking effect, but they would also reduce CTec2 adsorption on cellulose to decrease the enzymatic activity. The copolymer of lignin and polyethylene glycol (AL-PEG1000) has strong enhancement in enzymatic hydrolysis of lignocelluloses, because it not only improves the cellulase activity to cellulose, but also blocks the non-productive cellulase adsorption on lignin. Apart from improving the cellulase activity to cellulose, the enhancements of enzymatic hydrolysis of lignocellulose by adding AL-PEG1000 and SXPs are the result of the decreased cellulase non-productive adsorption on lignin.

  3. Improving rheology and enzymatic hydrolysis of high-solid corncob slurries by adding lignosulfonate and long-chain fatty alcohols.

    PubMed

    Lou, Hongming; Wu, Shun; Li, Xiuli; Lan, Tianqing; Yang, Dongjie; Pang, Yuxia; Qiu, Xueqing; Li, Xuehui; Huang, Jinhao

    2014-08-20

    The effects of lignosulfonate (SXSL) and long-chain fatty alcohols (LFAs) on the rheology and enzymatic hydrolysis of high-solid corncob slurries were investigated. The application of 2.5% (w/w) SXSL increased the substrate enzymatic digestibility (SED) of high-solid corncob slurries at 72 h from 31.7 to 54.0%, but meanwhile it increased the slurry's yield stress and complex viscosity to make the slurry difficult to stir and pump. The smallest molecular weight (MW) SXSL fraction had the strongest enhancement on SED. The SXSL fraction with large MW had a negative effect on rheology. n-Octanol (C8) and n-decanol (C10) improved the rheological properties of high-solid slurry and are strong enough to counteract the negative effect of SXSL. Furthermore, C8 and C10 clearly enhanced the enzymatic hydrolysis of high-solid corncob slurries with and without SXSL. A mechanism was proposed to explain the observed negative effect of SXSL and the positive effect of LFAs on the rheological properties.

  4. Effect of Polymyxin B, Tyrocidine, Gramicidin D, and Other Antibiotics on the Enzymatic Hydrolysis of Poly-β-Hydroxybutyrate

    PubMed Central

    Merrick, J. M.

    1965-01-01

    Merrick, J. M. (State University of New York, Buffalo). Effect of polymyxin B, tyrocydine, gramicidin D, and other antibiotics on the enzymatic hydrolysis of poly-β-hydroxybutyrate. J. Bacteriol. 90:965–969. 1965.—Previous studies have demonstrated that native poly-β-hydroxybutyrate (PHB) granules isolated from Bacillus megaterium are surrounded by a discrete membranelike structure. Morphological alterations of PHB granules are mainly characterized by membrane fragmentation, and can be correlated with decreased susceptibility of the polymer to enzymatic hydrolysis by soluble factors. In the present investigation, the inhibitory effect of a variety of surface-active and other antibiotics on the enzymatic depolymerization of PHB was examined. The most potent inhibitors were polymyxin B, tyrocidine, and gramicidin D. These polypeptide antibiotics are known to attack other types of membranous structures. The results, therefore, support previous evidence that the membrane or similar constituents of PHB granules are intimately involved in its metabolism. Chlortetracycline was also found to be a potent inhibitor of the depolymerization, but its mechanism of action may be different from the other antibiotics. The polymer-synthesizing enzyme(s), also localized on the granules, is inhibited by tyrocidine and gramicidin D but not by polymyxin B or chlortetracycline. PMID:4284918

  5. Volatile Compound, Physicochemical, and Antioxidant Properties of Beany Flavor-Removed Soy Protein Isolate Hydrolyzates Obtained from Combined High Temperature Pre-Treatment and Enzymatic Hydrolysis

    PubMed Central

    Yoo, Sang-Hun; Chang, Yoon Hyuk

    2016-01-01

    The present study investigated the volatile compound, physicochemical, and antioxidant properties of beany flavor-removed soy protein isolate (SPI) hydrolyzates produced by combined high temperature pre-treatment and enzymatic hydrolysis. Without remarkable changes in amino acid composition, reductions of residual lipoxygenase activity and beany flavor-causing volatile compounds such as hexanol, hexanal, and pentanol in SPI were observed after combined heating and enzymatic treatments. The degree of hydrolysis, emulsion capacity and stability, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, and superoxide radical scavenging activity of SPI were significantly increased, but the magnitudes of apparent viscosity, consistency index, and dynamic moduli (G′, G″) of SPI were significantly decreased after the combined heating and enzymatic treatments. Based on these results, it was suggested that the enzymatic hydrolysis in combination with high temperature pre-treatment may allow for the production of beany flavor-removed SPI hydrolyzates with superior emulsifying and antioxidant functionalities. PMID:28078256

  6. Enzymatic hydrolysis of cellulose: evaluation of cellulase culture filtrates under use conditions

    SciTech Connect

    Mandels, M.; Medeiros, J.E.; Andreotti, R.E.; Bissett, F.H.

    1981-09-01

    Culture filtrates from three mutant strains of Trichoderma reesei grown on lactose and on cellulose were compared under use conditions on four cellulose substrates. Cellulose culture filtrates contained five to six times as much cellulase as lactose culture filtrates. Unconcentrated cellulose culture filtrates produced up to 10% sugar solutions from 15% cellulose in 24 hours. Specific activity in enzyme assays and efficiency in saccharification tests were low for enzymes from all the mutants. Over a wide range the percent saccharification of a substrate in a given time was directly proportional to the logarithm of the ratio of initial concentrations of enzyme and substrate. As a result of this, dilute enzyme is more efficient than concentrated enzyme, but if high sugar concentrations are desired, very large quantities of enzyme are required. Since the slopes of these plots varied, the relative activity of cellulase on different substrates may be affected by enzyme concentration. (Refs. 28).

  7. Lignin enrichment and enzyme deactivation as the root cause of enzymatic hydrolysis slowdown of steam pretreated sugarcane bagasse.

    PubMed

    Wallace, Joshua; Brienzo, Michel; García-Aparicio, María P; Görgens, Johann F

    2016-05-25

    The enzymatic hydrolysis (EH) rate normally decreases during the hydrolysis, leaving unhydrolyzed material as residue. This phenomenon occurs during the hydrolysis of both cellulose (avicel) and lignocellulosic material, in nature or even pretreated. The progression of EH of steam pretreated sugarcane bagasse was associated with an initial (fast), intermediate (slower) and recalcitrant (slowest) phases, at glucan to glucose conversion yields of 61.7, 81.6 and 86%, respectively. Even though the EH of avicel as a simpler material than steam pretreated sugarcane bagasse, EH slowdown was present. The less thermo-stable endo-xylanase lost 58% of initial enzyme activity, followed by β-glucosidase that lost 16%, culminating in FPase activity loss of 30% in the first 24hours. After 72hours of EH the total loss of FPase activity was 40% compared to the initial activity. Analysis of the solid residue from EH showed that lignin content, phenolic compounds and ash increased while glucan decreased as hydrolysis progressed. During the initial fast phase of EH, the total solid residue surface area consisted predominantly of internal surface area. Thereafter, in the intermediate and recalcitrant phases of EH, the ratio of external:internal surface area increased. The proposed fiber damage and decrease in internal surface area, probably by EH action, was visualized by scanning electron microscopy imagery. The higher lignin/glucan ratio as EH progressed and enzyme deactivation by thermo instability were the main effects observed, respectively to substrate and enzyme.

  8. Seafood-like flavour obtained from the enzymatic hydrolysis of the protein by-products of seaweed (Gracilaria sp.).

    PubMed

    Laohakunjit, Natta; Selamassakul, Orrapun; Kerdchoechuen, Orapin

    2014-09-01

    An enzymatic bromelain seaweed protein hydrolysate (eb-SWPH) was characterised as the precursor for thermally processed seafood flavour. Seaweed (Gracilaria fisheri) protein after agar extraction was hydrolysed using bromelain (enzyme activity=119,325 U/g) at 0-20% (w/w) for 0.5-24 h. Optimal hydrolysis conditions were determined using response surface methodology. The proposed model took into account the interaction effect of the enzyme concentration and hydrolysis time on the physicochemical properties and volatile components of eb-SWPH. The optimal hydrolysis conditions for the production of eb-SWPH were 10% bromelain for 3h, which resulted in a 38.15% yield and a 62.91% degree of hydrolysis value. Three free amino acids, arginine, lysine, and leucine, were abundant in the best hydrolysate. Ten volatile flavours of the best eb-SWPH were identified using gas chromatography/mass spectrometry. The predominant odourants were hexanal, hexanoic acid, nonanoic acid, and dihydroactinidiolide. The thermally processed seafood flavour produced from eb-SWPH exhibited a roasted seafood-like flavouring.

  9. A novel mixing strategy for maximizing yields of glucose and reducing sugar in enzymatic hydrolysis of cellulose.

    PubMed

    Pal, Ramendra Kishor; Chakraborty, Saikat

    2013-11-01

    This work explores the effects of mixing on enzymatic hydrolysis of cellulose to innovate a novel mixing strategy that maximizes glucose and reducing sugar yields for production of cellulosic ethanol while reducing the power required for reactor mixing. Batch experiments of cellulose hydrolysis are performed under aseptic conditions for 72 h at various substrate loading (2-6% wt./vol.), where the reactor mixing is terminated after different intervals of time ranging from 0 to 72 h. We find that initial mixing for a certain 'optimal mixing time' followed by no mixing for the rest of the reaction time maximizes glucose and reducing sugar yields. We report a maximum of 26% and 31% increase in glucose and reducing yields, respectively, in case of optimal mixing over continuous mixing for 2% substrate loading. We obtain an algebraic expression that predicts that the optimal mixing time increases exponentially with substrate loading.

  10. Fish peptone development using enzymatic hydrolysis of silver carp by-products as a nitrogen source in Staphylococcus aureus media

    PubMed Central

    Fallah, Meysam; Bahram, Somayeh; Javadian, Seyed Roholla

    2015-01-01

    Fish peptone was produced using enzymatic hydrolysis of silver carp filleting by-products by alcalase and trypsin. Also, the efficiency of the hydrolysates as a nitrogen source in Staphylococcus aureus medium was compared with commercial TSB. The results indicated that the protein hydrolysate from alcalase and trypsin had high protein content (92.92%, 91.53 respectively), and degree of hydrolysis (4.94%, 4.6% respectively).The results showed that silver carp filleting waste can be an efficient source for fish peptone production as a nitrogen source for S. aureus medium. However, the type of the used proteolytic enzyme considerably affected the performance of the resulting peptone despite the same DH. Fish peptone produced by alcalese performed significantly (P < 0.05) better than commercial TSB as a media for the bacteria while the performance of the trypsin peptone was not as good as the commercial medium. PMID:25838893

  11. An advanced understanding of the specific effects of xylan and surface lignin contents on enzymatic hydrolysis of lignocellulosic biomass

    SciTech Connect

    Ju, Xiaohui; Engelhard, Mark H.; Zhang, Xiao

    2013-01-17

    A deep understanding of biomass recalcitrance has been hampered by the intricate and heterogeneous nature of pretreated biomass substrates obtained from random deconstruction methods. In this study, we established a unique methodology based on chemical pulping principles to create "reference substrates" with intact cellulose fibers and controlled morphological and chemical properties that enable us to investigate the individual effect of xylan, bulk, and surface lignin content on enzymatic hydrolysis. We also developed and demonstrated an X-ray photoelectron spectroscopy (XPS) technique for quantifying surface lignin content on biomass substrates. The results from this study show that, apart from its hindrance effect, xylan can facilitate cellulose fibril swelling and thus create more accessible surface area, which improves enzyme and substrate interactions. Surface lignin has a significant impact on enzyme adsorption kinetics and hydrolysis rate. Advanced understanding of xylan, bulk, and surface lignin effects provides critical information for an effective biomass conversion process.

  12. An advanced understanding of the specific effects of xylan and surface lignin contents on enzymatic hydrolysis of lignocellulosic biomass.

    PubMed

    Ju, Xiaohui; Engelhard, Mark; Zhang, Xiao

    2013-03-01

    In this study, chemical pulping techniques were applied to create a set of biomass substrates with intact lignocellulosic fibers and controlled morphological and chemical properties to allow the investigation of the individual effects of xylan and surface lignin content on enzymatic hydrolysis. A high resolution X-ray photoelectron spectroscopy technique was established for quantifying surface lignin content on lignocellulosic biomass substrates. The results from this study show that, apart from its hindrance effect, xylan can facilitate cellulose fibril swelling and thus create more accessible surface area, which improves enzyme and substrate interactions. Surface lignin has a direct impact on enzyme adsorption kinetics and hydrolysis rate. Advanced understanding of xylan and surface lignin effects provides critical information for developing more effective biomass conversion process. Published by Elsevier Ltd.

  13. Enzymatic hydrolysis of chitin pretreated by rapid depressurization from supercritical 1,1,1,2-tetrafluoroethane toward highly acetylated oligosaccharides.

    PubMed

    Villa-Lerma, Guadalupe; González-Márquez, Humberto; Gimeno, Miquel; Trombotto, Stéphane; David, Laurent; Ifuku, Shinsuke; Shirai, Keiko

    2016-06-01

    The hydrolysis of chitin treated under supercritical conditions was successfully carried out using chitinases obtained by an optimized fermentation of the fungus Lecanicillium lecanii. The biopolymer was subjected to a pretreatment based on suspension in supercritical 1,1,1,2-tetrafluoroethane (scR134a), which possesses a critical temperature and pressure of 101°C and 40bar, respectively, followed by rapid depressurization to atmospheric pressure and further fibrillation. This methodology was compared to control untreated chitins and chitin subjected to steam explosion showing improved production of reducing sugars (0.18mg/mL), enzymatic hydrolysis and high acetylation (FA of 0.45) in products with degrees of polymerization between 2 and 5.

  14. Development of quantitative extraction method of amygdalin without enzymatic hydrolysis from tonin(Persicae Semen) by high performance liquid chromatography.

    PubMed

    Hwang, Eun-Young; Lee, Sang-Soo; Lee, Je-Hyun; Hong, Seon-Pyo

    2002-08-01

    Tonin(Persicae Semen) is the herb medicine that contains amygdalin as a major ingredient. Amygdalin in water is decomposed into benzaldehyde, HCN, and glucose by emulsin, a hydrolysis enzyme in tonin. A useful and practical method for the optimum extraction condition of amygdalin without enzymatic hydrolysis is required. The extraction yield of amygdalin of natural formula tonin was 0.1% from crude powders, 1.4% from small pieces, 3.5% from half pieces and 2.4% from whole pieces. The extraction yield of amygdalin of outer shell-eliminated tonin was 0.3% from crude powders, 1.4% from small pieces, and 3.5% from half pieces and whole pieces respectively. The extraction yield of amygdalin was most high when using the size larger than half.

  15. Non-ionic Surfactants and Non-Catalytic Protein Treatment on Enzymatic Hydrolysis of Pretreated Creeping Wild Ryegrass

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Pan, Zhongli; Zhang, Ruihong; Wang, Donghai; Jenkins, Bryan

    Our previous research has shown that saline Creeping Wild Ryegrass (CWR), Leymus triticoides, has a great potential to be used for bioethanol production because of its high fermentable sugar yield, up to 85% cellulose conversion of pretreated CWR. However, the high cost of enzyme is still one of the obstacles making large-scale lignocellulosic bioethanol production economically difficult. It is desirable to use reduced enzyme loading to produce fermentable sugars with high yield and low cost. To reduce the enzyme loading, the effect of addition of non-ionic surfactants and non-catalytic protein on the enzymatic hydrolysis of pretreated CWR was investigated in this study. Tween 20, Tween 80, and bovine serum albumin (BSA) were used as additives to improve the enzymatic hydrolysis of dilute sulfuric-acid-pretreated CWR. Under the loading of 0.1 g additives/g dry solid, Tween 20 was the most effective additive, followed by Tween 80 and BSA. With the addition of Tween 20 mixed with cellulase loading of 15 FPU/g cellulose, the cellulose conversion increased 14% (from 75 to 89%), which was similar to that with cellulase loading of 30 FPU/g cellulose and without additive addition. The results of cellulase and BSA adsorption on the Avicel PH101, pretreated CWR, and lignaceous residue of pretreated CWR support the theory that the primary mechanism behind the additives is prevention of non-productive adsorption of enzymes on lignaceous material of pretreated CWR. The addition of additives could be a promising technology to improve the enzymatic hydrolysis by reducing the enzyme activity loss caused by non-productive adsorption.

  16. Structure of the oligomers obtained by enzymatic hydrolysis of the glucomannan produced by the plant Amorphophallus konjac.

    PubMed

    Cescutti, Paola; Campa, Cristiana; Delben, Franco; Rizzo, Roberto

    2002-11-29

    Dimers and trimers obtained by enzymatic hydrolysis of the glucomannan produced by the plant Amorphophallus konjac were analysed in order to obtain information on the saccharidic sequences present in the polymer. The polysaccharide was digested with cellulase and beta-mannanase and the oligomers produced were isolated by means of size-exclusion chromatography. They were structurally characterised using electrospray mass spectrometry, capillary electrophoresis, and NMR. The investigation revealed that many possible sequences were present in the polymer backbone suggesting a Bernoulli-type chain.

  17. Effect of steam explosion pretreatment on treatment with Pleurotus ostreatus for the enzymatic hydrolysis of rice straw.

    PubMed

    Taniguchi, Masayuki; Takahashi, Daisuke; Watanabe, Daisuke; Sakai, Kenji; Hoshino, Kazuhiro; Kouya, Tomoaki; Tanaka, Takaaki

    2010-10-01

    The effects of steam explosion (1.5 MPa, 1 min) on the treatment of rice straw with Pleurotus ostreatus were evaluated in terms of the change in composition of the components and the susceptibility to enzymatic hydrolysis. When rice straw was pretreated with a steam explosion prior to biological treatment, the treatment time required for obtaining a 33% net glucose yield was reduced to 36 days from 60 days. The reduction is probably due to loosening of networks of Klason lignin with sugar moieties and partial collapse of the structure during the biological treatment.

  18. Changes in plant cell-wall structure of corn stover due to hot compressed water pretreatment and enhanced enzymatic hydrolysis.

    PubMed

    Zhou, Wei; Yang, Maohua; Wang, Caixia; Liu, Jianfei; Xing, Jianmin

    2014-08-01

    Corn stover is a potential feedstock for biofuel production. This work investigated physical and chemical changes in plant cell-wall structure of corn stover due to hot compressed water (HCW) pretreatment at 170-190 °C in a tube reactor. Chemical composition analysis showed the soluble hemicellulose content increased with pretreatment temperature, whereas the hemicellulose content decreased from 29 to 7 % in pretreated solids. Scanning electron microscopy revealed the parenchyma-type second cell-wall structure of the plant was almost completely removed at 185 °C, and the sclerenchyma-type second cell wall was greatly damaged upon addition of 5 mmol/L ammonium sulfate during HCW pretreatment. These changes favored accessibility for enzymatic action. Enzyme saccharification of solids by optimized pretreatment with HCW at 185 °C resulted in an enzymatic hydrolysis yield of 87 %, an enhancement of 77 % compared to the yield from untreated corn stover.

  19. Effect of a milling pre-treatment on the enzymatic hydrolysis of carbohydrates in brewer's spent grain.

    PubMed

    Niemi, Piritta; Faulds, Craig B; Sibakov, Juhani; Holopainen, Ulla; Poutanen, Kaisa; Buchert, Johanna

    2012-07-01

    Millions of tonnes of brewer's spent grain (BSG) are annually produced worldwide as a by-product of the brewing industry. BSG has the potential to be a valuable source of food, chemicals and energy if cost-efficient fractionation methods can be developed. A 2-fold improvement in carbohydrate solubilisation could be achieved through the introduction of a milling step prior to enzymatic hydrolysis. Course and fine milled fractions were characterized by particle size distribution and light microscopy. Fine milling decreased particle size down to the micron level and this in turn improved the carbohydrate solubility yield by a multi-enzyme mixture from 23% up to 45%. Carbohydrate solubilisation could be further increased through the supplementation of this enzyme preparation with additional cellulases. The physical degradation caused by the milling also liberated soluble carbohydrates without the requirement of any enzymatic treatment.

  20. Susceptibility of a polycaprolactone-based root canal filling material to degradation. II. Gravimetric evaluation of enzymatic hydrolysis.

    PubMed

    Tay, Franklin R; Pashley, David H; Yiu, Cynthia K Y; Yau, Joyce Y Y; Yiu-fai, Mak; Loushine, Robert J; Weller, R Norman; Kimbrough, W Frank; King, Nigel M

    2005-10-01

    Polycaprola