• KSBB Journal
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• v.4 no.2
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• pp.78-86
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• 1989

The effective saccharification of cellulosic biomass to glucose is the most critical step for the conversion of renwable biomass to alternative liquid fuel. The enzymatic hydrolysis of biomass can be significantly enhanced provide the attrition milling media is added during hydrolysis. The enhancing mechanism of hydrolysis reaction in an agitated bead system was investigated. An attrition-reactor (bioattritor) which installed specially designed torque measuring apparatus was developed, and the potimal saccharification conditions of bioattritor were determined. The relationship between the power consumption required for agitation of attrition-milling media and enhanced extent of hydrolysis of biomass was compared to evaluatic economic feasibility of the process.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1403-1412
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• 2013

Ethanol fuel production from lignocellulosic biomass is emerging as one of the most important technologies for sustainable development. To use this biomass, it is necessary to circumvent the physical and chemical barriers presented by the cohesive combination of the main biomass components, which hinders the hydrolysis of cellulose and hemicellulose into fermentable sugars. This study evaluated the hydrolytic capacity of enzymes produced by yeasts, isolated from the soils of the Brazilian Cerrado biome (savannah) and the Amazon region, on sugarcane bagasse pre-treated with $H_2SO_4$. Among the 103 and 214 yeast isolates from the Minas Gerais Cerrado and the Amazon regions, 18 (17.47%) and 11 (5.14%) isolates, respectively, were cellulase-producing. Cryptococcus laurentii was prevalent and produced significant ${\beta}$-glucosidase levels, which were higher than the endo- and exoglucanase activities. In natura sugarcane bagasse was pre-treated with 2% $H_2SO_4$ for 30 min at $150^{\circ}C$. Subsequently, the obtained fibrous residue was subjected to hydrolysis using the Cryptococcus laurentii yeast enzyme extract for 72 h. This enzyme extract promoted the conversion of approximately 32% of the cellulose, of which 2.4% was glucose, after the enzymatic hydrolysis reaction, suggesting that C. laurentii is a good ${\beta}$-glucosidase producer. The results presented in this study highlight the importance of isolating microbial strains that produce enzymes of biotechnological interest, given their extensive application in biofuel production.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.448-452
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• 2016

This study is for the effective pretreatment and saccharification of lignocellulosic biomass for a transport fuel receiving attention. The waste water during the pretreatment of biomass is major factor for determining the price of biofuel. Therefore, we conducted high concentration of organosolv pretreatment for decline waste water and reusing the solvent. We confirmed effect of organosolv pretreatment by components analysis and enzymatic hydrolysis of pretreated biomass. The corn stover was used for and 99.5 wt% of ethanol as a organosolv pretreatment. The pretreatment condition was varied 130 to $190^{\circ}C$ during the designated reaction times and the effect of pretreatment was investigated by enzymatic hydrolysis. The highest glucose conversion was more than 68% the pretreatment condition of $190^{\circ}C$ for 70 min or more. The solid remaining was more than 70% and almost of cellulose and hemicellulose were survived.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.4
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• pp.329-333
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• 2005

This study was designed to investigate the stability of a lipase fused with a cellulose­binding domain (CBD) to cellulase. The fusion protein was derived from a gene cluster of a CBD fragment of a cellulase gene in Trichoderma hazianum and a lipase gene in Bacillus stearother­mophilus L1. Due to the CBD, this lipase can be immobilized to a cellulose material. Factors affecting the lipase stability were divided into the reaction-independent factors (RIF), and the re­action-dependent factors (RDF). RIF includes the reaction conditions such as pH and tempera­ture, whereas substrate limitation and product inhibition are examples of RDF. As pH 10 and $50^{\circ}C$ were found to be optimum reaction conditions for oil hydrolysis by this lipase, the stability of the free and the immobilized lipase was studied under these conditions. Avicel (microcrystal­line cellulose) was used as a support for lipase immobilization. The effects of both RIF and RDF on the enzyme activity were less for the immobilized lipase than for the free lipase. Due to the irreversible binding of CBD to Avicel and the high stability of the immobilized lipase, the enzyme activity after five times of use was over $70\%$ of the initial activity.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.43-49
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• 2006

The surface and pore structure of cellulose fibers have a significant impact on the properties and performance in applications. Cellulase enzymatic hydrolysis of cellulose fibers can result in changes to the surface and pore structure thus providing a useful tool for fiber modification. This research characterizes these changes using various test methods such as fiber dimension, water retention value, hard-to-remove water content, freezing and non-freezing bound water content, polymer adsorption, and crystallinity index. For a high-dosage enzyme treatment (0.10 g/g), the fiber length was significantly decreased and the fibers were 'cut' in the cross direction, not in the axial direction. The swelling capacities as measured by the WRV and HR water content increased for the high-dosage treatment. Three independent measurements (non-freezing bound water, polymer adsorption, and crystallinity index) are in good agreement with the statement that the amorphous regions of cellulose fibers are a more readily available substrate relative to crystalline regions. Based on the experimental results obtained herein, a model was proposed to explain surface and pore structure modification of cellulose fibers via enzymatic treatment.

• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.250-255
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• 2013

As a renewable nanomaterial, cellulose nanocrystal (CNC) isolated from wood grants excellent mechanical properties in developing high performance nanocomposites. This study was undertaken to compare the reinforcing efficiency of two different CNCs, i.e., cellulose nanowhiskers (CNWs) and cellulose nanofibrils (CNFs) from hardwood bleached kraft pulp (HW-BKP) as reinforcing agent in polyvinyl alcohol (PVA)-based nanocomposite. The CNWs were isolated by sulfuric acid hydrolysis while the CNFs were isolated by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. Based on measurements using transmission electron microscopy, the individual CNWs were about $6.96{\pm}0.87nm$ wide and $178{\pm}55nm$ long, while CNFs were $7.07{\pm}0.99nm$ wide. The incorporation of CNWs and CNFs into the PVA matrix at 5% and 1% levels, respectively, resulted in the maximum tensile strength, indicating different efficiencies of these CNCs in the nanocomposites. Therefore, these results suggest a relationship between the reinforcing potential of CNCs and their physical characteristics, such as their morphology, dimensions, and aspect ratio.

• Textile Coloration and Finishing
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• v.8 no.4
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• pp.42-51
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• 1996

Alkaline hydrolysis to improve the hand of PET/acetate union fabric was studied in relation to skin saponification and retarding effect of salts on the alkaline hydrolysis of cellulose acetate fiber, accelerating effect of salts on the alkaline hydrolysis of PET fiber, and changes of total hand value(T.H.V) of PET/acetate union fabric treated with alkali/salt solution. It was found that the rate of saponification of acetate was delayed by the addition of salts such as LiCl, NaCl and CH$_{3}$COONa into NaOH solution below 10 minutes. The rate of shrinkage of acetate fabric treated with 5g/l NaOH solution at 9$0^{\circ}C$ and 60 minutes showed 20 % but it was decreased 8% by. the addition of 120g/l Concentration of inorganic salts. We could know that the rate of alkaline hydrolysis of filament yarn treated with alkali solution at 9$0^{\circ}C$ and 60 minutes was delayed about 3 % using 2,000T/M of hard twist yarn, especially acetate filament treated with alkali solution at 9$0^{\circ}C$ and 10 minutes was delayed about 10%. T.H.V. of PET/acetate union fabric was increased from 2.77 to 3.04~3.18 by the addition of salts into alkali solution.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.514-517
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• 1999

Hydrolysis of EFB (empty fruit bunch) derived from oil palm was studied using crude enzyme from Aspergillus terreus IMI 282743 along with commercial enzymes from Trichoderma reesei and Aspergillus niger. Hydrolysis at $40^{\circ}C$ and $50^{\circ}C$ with $\alpha$-cellulose or EFB gave significantly lower yield when commercial enzymes of T. reesei and A. niger were used and the hydrolysis time extended beyond 10 h. After 24 h of hydrolysis at $40^{\circ}C$ and $50^{\circ}C$, the filter paper activity (Fpase) from A. terreus retained as much activity as A. niger and it was significantly higher than T. reesei. Glucose concentration of 0.25% and 0.5% caused significant inhibition in the crude enzyme, but in regards to the commercial enzymes it only showed a slight effect. Crude enzymes from A. terreus could produce the highest reducing sugars when compared to commercial enzymes from T. reesei or A. niger. Nevertheless, low yield of sugar was observed for EFB for all treatments.

• Elastomers and Composites
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• v.50 no.1
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• pp.62-67
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• 2015

The surface modification of microfibriled cellulose (MFC) was carried out through the hydrolysis-condensation reaction using (3-aminopropyl)triethoxysilane (APS) and 3-glycidyloxypropyltriethoxysilane (GPS) and then the modified cellulose was compounded with bio-degradable poly(lactic acid) (PLA). Also, pristine MFC was compounded with PLA as a control groups. The confirmation of surface modification for the pristine MFC was characterized by FT-IR and SEM/EDX. The thermal and mechanical properties of the PLA/MFC composites depended on the content of MFC and the type of silane coupling agents. From the thermal, morphological and mechanical behaviors of the PLA/MFC composites, it was found that GPS-MFC was more successful to improve the interface adhesion between PLA matrix and the surface of MFC than that of APS-MFC.

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.7
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• pp.1075-1081
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• 2008

Eco-friendly processing using enzymes has been focused in textile industry in order to reduce environmental pollutions. This paper was suggested to hydrolyze non-cellulose, such as fats and waxes in cotton fabrics by lipase treatment. Enzymatic treatment conditions were controlled according to pH, temperature, enzyme concentration, and treatment time. The physical properties of the lipase-treated cotton fabrics were evaluated by measuring weight loss, moisture regain and dyeing properties. The surface morphology of lipase-treated cotton fabrics were observed by SEM. As a result, the optimum conditions for the lipase treatment were at pH 4.2, temperature 50$^{\circ}C$, concentration 50%, and treatment time 90 minutes. Calcium chloride and Triton X-100 were effective auxiliaries in lipase treatment.