• Journal of the Korean Wood Science and Technology
• /
• v.52 no.2
• /
• pp.101-117
• /
• 2024

The conversion characteristics of the major components of Liriodendron tulipifera were investigated during acid-catalyzed organosolv pretreatment. Glucan in L. tulipifera was slowly hydrolyzed, whereas xylan was rapidly hydrolyzed. Simultaneous hydrolysis and degradation of xylan and lignin occurred; however, after complete hydrolysis of xylan at higher temperatures, lignin remained and was not completely degraded or solubilized. These conversion characteristics influence the structural properties of glucan in L. tulipifera. Critical hydrolysis of the crystalline regions in glucan occurred along with rapid hydrolysis of the amorphous regions in xylan and lignin. Breakdown of internal lignin and xylan bonds, along with solubilization of lignin, causes destruction of the lignin-carbohydrate complex. Over a temperature of 160℃, the lignin that remained was coalesced, migrated, and re-deposited on the surface of pretreated solid residue, resulting in a drastic increase in the number and content of lignin droplets. From the results, the characteristic conversions of each constituent and the changes in the structural properties in L. tulipifera effectively improved enzymatic hydrolysis in the range of 140℃-150℃. Therefore, it can be concluded that significant changes in the biomass recalcitrance of L. tulipifera occurred during organosolv pretreatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.3
• /
• pp.44-49
• /
• 2014

The mushroom cultured waste(MCW) from cork oak was evaluated as the raw material for bioethanol production. For enzymatic hydrolysis, cellulase cocktails (Celluclast 1.5L and Novozym 188) was used for polysaccharides to monosaccharides conversion. Compared with sound cork oak woodmeal, woodmeal from MCW showed higher cellulose to glucose conversion. To improve polysaccharides to monosaccharides conversion, pretreatment by sodium hydroxide was applied. Even though more xylan and lignin were removed in woodmeal of MCW than that of cork oak, concentration of glucose was higher from sodium hydroxide treated cork oak woodmeal (51.3 g/L) than treated MCW woodmeal (41.6 g/L).

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.2
• /
• pp.218-230
• /
• 2016

The effect of steam explosion coupled with alkali (1% sodium hydroxide, 1% potassium hydroxide and 15% sodium carbonate) or organosolv solvent (85% methanol, 70% ethanol and dioxane) on the production of sugar, changes in the chemical composition of M. sinensis were evaluated. The steam explosion coupled with 1% potassium hydroxide and dioxane were better as compared with other treatments based on the removals of acid insoluble lignin, and about 89.0% and 85.4%. Enzymatic hydrolysis of steam explosion with 1% potassium hydroxide and dioxane treated M. sinensis, gave a 98.0% and 96.5% of glucose conversion, respectively. These results suggested that pretreatment of M. sinensis with either potassium hydroxide or dioxane could be a promising pretreatment method for glucose production.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.504-507
• /
• 2000

Enzymatic hydrolysis of cellulose was studied with emphasis on the effect of cellulase loading and pulp sludge concentration on glucose yield. Enzyme loading appeared to have a significant effect on glucose yield. Chemical pretreatment had no effect on enzymatic hydrolysis of pulp sludge. High glucose yield was obtained from enzymatic hydrolysis, especially at sludge concentrations lower than twenty percent. The optimum concentrations of crude cellulase and ${\beta}-glucosidase$ were 5 U/mL and 8 U/mL, respectively, considering the amount of enzymes used and glucose produced.

• Journal of the Korean Wood Science and Technology
• /
• v.45 no.2
• /
• pp.232-242
• /
• 2017

The objective of this study was to examine changes in the porosity and internal structure of wood as it goes through the process of saccharification (extraction of fermentable sugars). This study also examined the use of different drying methods to prepare samples for characterization of internal pores, with particular emphasis on the partially disrupted cell wall. Aspen wood flour samples after dilute acid pretreatment followed by enzymatic hydrolysis were examined for nitrogen adsorption. The resulting isotherms were analyzed for surface area, pore size distribution, and total pore volume. Results showed that freeze drying (with sample pre-freezing) maintains the cell wall structure, allowing for examination of saccharification effects. Acid pretreatment (hemicellulose removal) doubled the surface area and tripled the total volume of pores, which were mostly 10-20 nm wide. Subsequent enzymatic hydrolysis (cellulose removal) caused a 5-fold increase in the surface area and a ~ 11-fold increase in the total volume of pores, which ranged from 5 to 100 nm in width. These results indicate that nitrogen adsorption analysis is a feasible technique to examine the internal pore structure of lignocellulosic residues after saccharification. The information on the pore structure will be useful when considering value-adding options for utilizing the solid waste for biofuel production.

• Journal of Korea Foresty Energy
• /
• v.20 no.2
• /
• pp.20-27
• /
• 2001

An effective method for production of glucose was developed using enzymatic hydrolysis of Suwon poplar by the cellulase. Enzymatic hydrolysis of wood is the reaction to produce glucose from wood using enzyme which derives from microorganism. Glucose can be transferred easily to ethanol by fermentation. Ethanol is the starting material for producing acetone, butanol, citric acid and lactic acid. The mechanism of the enzymatic hydrolysis of cellulose are reasonably explained in terms of the sequential action of three different types of enzymes, endo-cellulase, ex-cellulase, and $\beta$ -glucosidase. The goal of this work was to investigate the cellulose hydrolysis pretreated polar with various concentration NaOH, the crystallinity of cellulose, lignin contents and the degree of hydrolysis.

• Journal of Forest and Environmental Science
• /
• v.26 no.2
• /
• pp.137-148
• /
• 2010

The high costs for ethanol production with lignocellulosic biomass as a second generation energy materials currently deter commercialization of lignocellulosic biomass, especially wood biomass which is considered as the most recalcitrant material for enzymatic hydrolysis mainly due to the high lignified structure and the nature of the lignin component. Therefore, overcoming recalcitrance of lignocellulosic biomass for converting carbohydrates into sugar that can subsequently be converted into biobased fuels and biobased products is the primary technical and economic challenge for bioconversion process. This study was mainly reviewed on the research trend of the enhancement of enzymatic hydrolysis for lignocellulosic biomass after pretreatment in bioethanol production process.

• Journal of Environmental Health Sciences
• /
• v.31 no.4 s.85
• /
• pp.294-300
• /
• 2005

Food waste can be a valuable carbon source in biological nutrient removal (BNR) systems because of high C/N and C/P ratios. However, food waste should be pretreated to promote its hydrolysis rate because hydrolysis reaction would be a rate-limiting step. This study investigates the influence of the enzymatic pretreatment on acid fermentation of food waste. Solubilization of particulate matter in food waste by using commercial enzymes was examined. The acidification efficiency and the volatile fatty acids (VFAs) production potential of enzymatically pretreated food waste were also examined. The highest volatile suspended solids (VSS) reduction was obtained with an enzyme mixture ratio of 1:2:1 of carbohydrase:protease:lipase. An optimum enzyme dosage for solubilization of food waste was $0.1\%$(V/V) with the enzyme mixture ratio of 1:2:1. In the acid fermentation of enzymatically pretreated food waste, $0.1\%$(V/V) enzyme mixture dosage for pretreatment result in the maximum VFAs production and the best VFAs fraction in soluble COD(SCOD). The VFAs production at this addition level was 3.3 times higher than that of no-enzyme added fermenter. The dominant VFAs present was n-butyrate followed by acetate.

• Korean Chemical Engineering Research
• /
• v.52 no.1
• /
• pp.113-118
• /
• 2014

We have investigated the combined pretreatment of electron beam irradiation (EBI) and water steam as a kenaf core pretreatment process. After each sample was exposed to electron beam dose ranging from 50 to 1,000 kGy, the irradiated sample was treated by water steam using an autoclave for 5-h at $120^{\circ}C$. The pretreated samples were characterized using FTIR-ATR and XRD. FTIR spectra and XRD analysis of nonpretreated and pretreated samples confirm that crystallinity changes were observed before and after the pretreatment. The crystallinity index (CrI) was increased from 50.6% for nonpretreated sample 55.0% for 500 kGy exposed sample. And then, we analyzed sugar yield that is the amount of produced mono-saccharides in pretreated sample by enzymatic hydrolysis; an enzyme activity rate was 70 FPU/mL and 40 CBU/mL, and the loading time was 24, 48 and 72-h. The highest sugar yield was 83.9% at 500 kGy after 72-h for enzymatic hydrolysis. The sugar yield of enzymatic hydrolysis for pretreatment samples was increased as doses are subsequently changed to 100, 200 and 300 kGy, allowing to give 50.8%, 58.6% and 67.9%, respectively.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.3
• /
• pp.197-203
• /
• 1992

Studies of the pretreatment of chitin and its subsequent hydrolysis by Aspergillus carneus chitinase are reported. Ball milling was found to be the most effective way among the pretreatment methods tested. Data are presented describing the effect of enzyme and substrate concentrations on the rate and extent of the hydrolysis process. It was found that the successive addition of enzyme improved the saccharification yield. Significant product inhibition of the chitinase was observed when N-acetylglucosamine concentration was 3.6％ or higher. Adsorption of enzymes to the substrate occurred during a 24 hr hydrolysis period. An initial rapid and extensive adsorption occurred, followed by gradual desorption which increased during the time of reaction. Intermediate removal of the hydrolyzate and continuation of the hydrolysis by adsorbed enzyme on the residual chitin was also investigated. A total of 75.4 g/l reducing sugars, corresponding to 69.2％ saccharificaton yield (as N-acetylglucosamine) was obtained. In addition an increase in the amount of recoverable enzymes was observed under these conditions. Evidence presented here suggests that the technique, whereby the free enzymes in the recovered hydrolyzate are re-adsorbed onto the new substrate, may provide a means of recirculating the dissolved enzymes.