• Journal of the Korean Wood Science and Technology
• /
• v.39 no.2
• /
• pp.187-195
• /
• 2011

In this study, dilute acid pretreatment of $Liriodendron$ $tulipifera$ was performed for enzymatic hydrolysis. As the pretreatment temperature was increased, enzymatic hydrolysis and enzyme adsorption yield also increased. The highest enzymatic hydrolysis yield was 57% (g/g) and enzyme adsorption was 44% (g/g). Enzymatic hydrolysis yield was determined with weight loss of pretreated biomass by enzyme, and enzyme adsorption was a percentage of enzyme weight attaching on pretreated biomass compared with input enzyme weight. When $L.$ $tulipifera$ was pretreated with 1% sulfuric acid at $160^{\circ}C$ for 5 min., hemicellulose was significantly removed in pretreatment, but the lignin contents were constant. Other changes in surface morphology were detected on biomass pretreated at $160^{\circ}C$ by a field emission scanning electron microscope (FESEM). A large number of spherical shapes known as lignin droplets were observed over the entire biomass surface after pretreatment. Hemicellulose removal and morphological changes improved enzyme accessibility to cellulose by increasing cellulose exposure to enzyme. It is thus evidence that enzyme adsorption is a significant factor to understand pretreatment effectiveness.

• Journal of the Korean Wood Science and Technology
• /
• v.34 no.6
• /
• pp.81-95
• /
• 2006

In order to investigate the possibility of waste logs after oak mushroom production as a source of an alternative energy and to obtain the fundamental data of supercritical water hydrolysis that has been paid attention as a new saccharification method of lignocellulosics, supercritical water hydrolysis of normal log woods (Quercus acutissima Carruth) and waste logs was carried out. With the increase of reaction time and temperature, the color of the degradation products has been dark and the degradation rate and the crystalline index increased. However the increase of reaction pressure affected the color of the degradation products and the degradation rate at only low reaction temperature. In the early stage of the reaction, the degradation of hemicellulose was progressed, while in the late stage, the cellulose was degraded. The increase of reaction time and reaction temperature (less than $415^{\circ}C$) improved the sugar yield, while at high temperature(more than $415^{\circ}C$), the sugar yield was decreased. Based on the result of the sugar yield, the optimal hydrolysis condition of Q. acutissima Carruth by supercritical water was determined to be $415^{\circ}C$, 60 seconds and 230 pressure bar with the sugar yield of 2.68% (w/w). At the optimal condition, the supercritical water hydrolysis of waste logs after the mushroom production was carried out and the sugar yield was increased to 358% (w/w). The major degradation products of waste logs by supercritical water hydrolysis were 1,1'-oxybis-benzene and 1,2-benzendicarboxylic acid by the GC-MS analysis. At the reaction condition with low degradation rate, the fatty acids such as pentadecanoic acid, 14-methyl-heptadecanoic acid were identified. With the increase of the reaction temperature and time, the amounts of phenol and benzene were increased, but the reaction pressure did not affect the kinds of degradation products. Holocellulose content was 60.6~79.2% in the water insoluble residue and the monosaccharide yield of the water insoluble residue was 49.2~675% by the acid hydrolysis. The monosaccharide yield of water-soluble portion was increased largely by the second hydrolysis using dilute acid.

• Korean Chemical Engineering Research
• /
• v.50 no.1
• /
• pp.141-148
• /
• 2012

In order to study the utilization of brown seaweed Laminaria japonica as an alternative renewable feedstock for bioethanol production, the properties of acid hydrolysis and ethanol fermentation were investigated. The acid hydrolysis enhanced the final yield of fermentable sugars, which led great increase of ethanol productivity. The maximum yield of reducing sugars reached 135 mg/g-dry Laminaria japonica after 1.0N sulfuric acid-hydrolysis at $130^{\circ}C$ for 6 h. The Saccharomyces cerevisiae (ATCC 24858) could ferment $C_6$-sugars like glucose, galactose and mannose into ethanol, but not $C_5$-sugars like arabinose and xylose. Optimal fermentation time varied with sugars; 48 h for glucose, 72 h for galactose, and 96 h for mannose. Nevertheless, the ethanol yield from the hydrolysate reached 242 mg/g-dry Laminaria japonica after fermentation by the S. cerevisiae at $35^{\circ}C$ for 96 h, which corresponds to approximately 4 times more than the theoretical yield from total reducing sugars in the hydrolysates. It indicates that the non-reducing sugars or oligosaccharides dissolved in the hydrolysate played an important role in producing bioethanol. The ethanol concentration linearly increased from 2.4 to 9.2 g/L, while the ethanol yield per dry weight of biomass decreased from 242 to 185 mg/g, with increasing the ratio of biomass to acid solution from 1 to 5% (w/v). The bioethanol yield estimated was approximately 7,400~9,600 kg/ha/year, and indicated that Laminaria japonica is a promissing feedstock for bioethanol production.

• 한국생물공학회:학술대회논문집
• /
• 2000.04a
• /
• pp.459-462
• /
• 2000

The pretreatment of used newspaper for the enzymatic digestion preprocess was performed on a percolation reactor and a batch reactor. The test condition of percolation process was $170^{circ}C$, 60min, 1 mL/min, and 400psi, that of batch was $40^{circ}C$, 3hr. and latm Reaction solutions used in pretreatment process were aqueous ammonia, sulfuric acid, water, and hydrogen-peroxide as an oxidizing agent. As a result, the effect of pretreatment was similar to batch and percolation process, but the yield of enzymatic hydrolysis was higher in batch than percolation. This batch pretreatment enhanced enzymatic hydrolysis rate and increased glucose yield from about 15 to 20%. The inhibition factors influenced the rate of enzymatic hydrolysis was investigated, and the ink contented newspaper was the major factor.

• Journal of Life Science
• /
• v.12 no.6
• /
• pp.765-768
• /
• 2002

Enantioselective hydrolysis of racemic styrene oxide by Rhodotorula sp. CL-82 was investigated. Reaction conditions including pH, temperature, and volume ratio of organic cosolvent were optimized using response surface methodology, and the optimal conditions of pH, temperature, and the volume ratio of cosolvent were determined to be 7.64, $33.26^{\circ}C$, and 3.09 %(v/v), respectively. Chiral (S)-phenyl oxirane could be obtained with high enantiomeric purity (ee ＞ 99%) and 20% yield (theoretical yield ＝ 50%) at the optimal rendition.

• Korean Journal of Food Science and Technology
• /
• v.25 no.5
• /
• pp.589-591
• /
• 1993

Effects of enzymatic hydrolysis of polysaccharides with using three commercial mixed enzymes (Ultrazyme, Celluclast, Viscozyme) were investigated on supernatant ratio, solid yields and viscosity of sea mustard extracts. The result showed that enzymatic hydrolysis prior to extraction increased the solids concentration up to 27.3% and the solids yield up to 14.0%. However the supernatant ratio after centrifugation of the sea mustard suspension was rather reduced. The viscosity of the extracts was significantly increased during initial enzymatic hydrolysis.

• Korean Chemical Engineering Research
• /
• v.54 no.5
• /
• pp.587-592
• /
• 2016

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for portable proton exchange membrane fuel cells (PEMFCs). Properties of $NaBH_4$ hydrolysis reaction using unsupported Co-P-B Co-B, catalyst at high concentration $NaBH_4$ solution were studied. In order to enhance the hydrogen generation yield at high concentration of $NaBH_4$, the effect of catalyst type, $NaBH_4$ concentration and recovery of condensing water on the hydrogen yield were measured. The yield of hydrogen evolution increased as the boron ratio increased in preparation process of Co-P-B catalyst. The hydrogen yield decreased as the concentration increased from 20 wt% to 25 wt% in $NaBH_4$ solution during hydrolysis reaction using 1:5 Co-P-B catalyst. Maximum hydrogen yield of 96.4% obtained by recovery of condensing water and thinning of catalyst pack thickness in reactor using Co-P-B with Co-B catalyst and 25 wt% $NaBH_4$ solution.

• Korean Chemical Engineering Research
• /
• v.49 no.4
• /
• pp.470-474
• /
• 2011

Rice straw is the main grain straw and is produced in large quantities every year in Korea. Pretreatment of lignocellulosic biomass using soaking process was carried out mild conditions at atmospheric pressure and temperature of $60^{\circ}C$. We found enzymatic hydrolysis condition of pretreated biomass. In case of a rice straw, compared with previous lignocellulosic biomass, we found that hydrolysis time was a shorter than others. Hydrolysis of SAA-treated rice straw has shown conversion rate was higher at $50^{\circ}C$. Hydrolysis was ended between 40~48 hour. Glucose conversion rate was higher when enzyme loading is 65 FPU/ml and 32 CbU/ml. When substrate concentration was 5%(w/v), it was that conversion rate was 83.8% after hydrolysis for 72 hr. In simultaneous saccharification and fermentation(SSF) experiment about SAA-treated rice straw, ethanol productive yield was highest from $40^{\circ}C$. The yield of that time was 33.05% from 48 hour.

• Archives of Pharmacal Research
• /
• v.18 no.6
• /
• pp.454-457
• /
• 1995

To improve the yield of genuine aglycones from glycosides, the conditions of alkaline hydrolysis were investigated, and a modified method was established. The modified method empolyed pyridine as an aprotic solvent. To complete the hydrolysis and obtain 20(S)-protopanaxadiol (1) and 20(S)-protopanaxatriol(2), which are the genuine aglycones of ginsenosides, total ginsenosides were refluxed with sodium methoxide in pyridine. Addition of methanol, a protic polar solvent to the reaction miuxture, led partial hydrolysis yielding a mixture of the genuine prosapogenols. Of the prosapogenols compound 3 and 6 characteristically possessed D-glucopyranosyl moiety attached at the sterically hindered C-20 hydroxyl group. 3 and 6 were not obtaijned by other hydrolysisw methods except by the soil bacterial hydrolysis.

• Proceedings of the Korea Society of Poultry Science Conference
• /
• 2004.11a
• /
• pp.26-27
• /
• 2004

This study was conducted to evaluate the value of chicken keel cartilage as a source of mucopoly-saccharide-protein containing chondroitin sulfate (CS) and to find the optimum extraction conditions. The hot water extraction and alcalase hydrolysis methods were performed for extraction mucopolysaccharide in lyophilized chicken keel cartilage. The most efficient condition was hydrolysis with 2 % alcalase in 10 volumes of distilled water for 120 min. The yield of hydrolysate and CS content were 75.87 % and 25.61 %, respectively. For further separation of CS from hydrolysate by alcalase, ethanol precipitation was performed. The yield of ethanol precipitate and its CS content were 21.41 % and 46.31 %, respectively.