• Journal of the Korean Wood Science and Technology
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• 제52권2호
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• pp.101-117
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• 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.

• 한국미생물·생명공학회지
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• 제15권5호
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• pp.334-339
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• 1987

Pyruvic acid 생산 미생물로부터 얻어진 pyruvic acid의 tryptophan으로의 효소적 전환을 조사하였다. 발광 미생물인 Beneckea sp.가 pyruvic acid의 생산에 사용되었다. pyruvic acid, indole과 ammonia로 부터 tryptophan을 합성하는 tryptophanase의 효소원으로 Enterobacter aerogenes ATCC10031의 균체가 반응용액에 직접 사용되었다. Tryptophan의 생산량을 증가시키기 위해, 비이온성 계면활성제와 비 수용성 유기용매가 indole의 저장소로 사용되었다. 비이온성 계면활성제의 경우 triton X-100은 매우 효과적이였다. 1.5%의 triton X-100 이 사용되었을 때, 37$^{\circ}C$에서 48시간 동안에 7.7g/$\ell$의 tryptophan이 생산되었다. 비수용성 유기용매의 경우 10%의 benzene이 사용되었을 때, 37$^{\circ}C$에서 48시간 동안에 8.7g/$\ell$의 tryptophan이 생산되었다. 이 tryptophan의 양은 indole과 pyruvic acid를 기준으로 각각 48%와 36%의 전환율에 해당한다.

• KSBB Journal
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• 제26권4호
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• pp.347-351
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• 2011

In this study, we investigated the effect of reaction factors on enzymatic hydrolysis of Hizikia fusiforme, which is brown algae in marine biomass resource, using commercial enzymes. The composition of H. fusiforme is 38.9% of reducing sugar, 4.8% of moisture, 17.8% of ash, and 38.5% of others. In the condition of 1-5% substrate, the increase of substrate concentration enhanced the increase of reducing sugar formation; however, the hydrolysis yield did not increase after 24 h. After reaction of 75 h, conversion yield of reducing sugar were obtained to 16.45%, 17.99%, and 14.55% at 1, 2.5, and 5% substrate, respectively. As a result of effect of enzyme amount, the formation of reducing sugar did not show considerable change at 1% substrate. However, in the condition of 2.5% substrate, the great change of reducing sugar formation was observed by the increase of enzyme amount. The conversion yields of reducing sugar were obtained to 18.77% and 22.83% at 1% and 2.5% substrate with 30% enzyme, respectively. As a result of heat treatment of biomass, the high yield was obtained in 2.5% substrate and the yields were increased to 0.06-7.2% by the heat treatment. This result will provide the basic information for production process of biofuels and chemicals from marine biomass H. fusiforme.

• Journal of Microbiology and Biotechnology
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• 제1권1호
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• pp.54-62
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• 1991

Cyclodextrin glucanotransferase(CGTase) derived from Bacillus macerans was immobilized by (1) covalent linkage on chitosan and chitin with glutaraldehyde, (2) adsorption on DEAE-cellulose and Amberite IRA 900 after succinylation, and (3) entrapment on alginate and polyacrylamide by cross linking. Adsorption on Amberite IRA 900 and covalent linking on chitosan were identified to be the most suitable immobilization methods considering the yield of activity and stability of immobilized CGTase. The enzymatic properties of immobilized CGTase were investigated and compared with those of the soluble CGTase. Thermal stability of CGTase immobilized on chitosan was increased from 50 to $55^{\circ}C$, and the optimum temperature of CGTase immobilized on Amberite IRA 900 was shifted from 55 to $50^{\circ}C$. The effect of molecular size of soluble starch (substrate) on immobilized CGTase investigated using partially liquefied substrates with different dextrose equivalent(DE). Cyclodextrin(CD) conversion yield augmented according to the increase of DE level for immobilized CGTase on Amberite IRA 900. CD conversion yield of partially cyclized starch with soluble CGTase was higher compared with liquefied one with ${\alpha}-amylase$.

• Journal of Ginseng Research
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• 제38권4호
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• pp.264-269
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• 2014

Background: In this study, we examined the effects of various enzymes on chemical conversions of ginsenosides in ginseng extract prepared by amylases. Methods: Rapidase, Econase CE, Viscozyme, Ultraflo L, and Cytolase PCL5 were used for secondary enzymatic hydrolysis after amylase treatment of ginseng extract, and ginsenoside contents, skin permeability, and chemical compositions including total sugar, acidic polysaccharide, and polyphenols were determined on the hydrolyzed ginseng extract. Results: Rapidase treatment significantly elevated total ginsenoside contents compared with the control (p < 0.05). In particular, deglycosylated ginsenosides including Rg3, which are known as bioactive compounds, were significantly increased after Rapidase treatment (p < 0.05). The Rapidase-treated group also increased the skin permeability of polyphenols compared with the control, showing the highest level of total sugar content among the enzyme treatment groups. Conclusion: This result showed that Rapidase induced the conversion of ginsenoside glycosides to aglycones. Meanwhile, Cytolase PCL5 and Econase treatments led to a significant increase of uronic acid (acidic polysaccharide) level. Taken together, our data showed that the treatments of enzymes including Rapidase are useful for the conversion and increase of ginsenosides in ginseng extracts or products.

• Korean Chemical Engineering Research
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• 제53권2호
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• pp.216-223
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• 2015

The present work explores the potential of wet air oxidation (WAO) for pretreatment of mixed lignocellulosic biomass to enhance enzymatic convertibility. Rice husk and wheat straw mixture (1:1 mass ratio) was used as a model mixed lignocellulosic biomass. Post-WAO treatment, cellulose recovery in the solid fraction was in the range of 86% to 99%, accompanied by a significant increase in enzymatic hydrolysis of cellulose present in the solid fraction. The highest enzymatic conversion efficiency, 63% (by weight), was achieved for the mixed biomass pretreated at $195^{\circ}C$, 5 bar, 10 minutes compared to only 19% in the untreated biomass. The pretreatment under the aforesaid condition also facilitated 52% lignin removal and 67% hemicellulose solubilization. A statistical design of experiments on WAO process conditions was conducted to understand the effect of process parameters on pretreatment, and the predicted responses were found to be in close agreement with the experimental data. Enzymatic hydrolysis experiments with WAO liquid fraction as diluent showed favorable results with sugar enhancement up to $10.4gL^{-1}$.

• 한국안광학회지
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• 제5권1호
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• pp.89-94
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• 2000

메틸프록토시드 아크릴레이트와 메타크릴레이트를 효소적 배당화법으로 합성한 결과, 아크릴산과 메타크릴산의 배당화 전화율은 각각 78%나 93%이었으며, 연성콘택트렌즈용 의용고분자를 제조하기 위한 생체 친화성 단량체로서 활용될 것으로 기대된다.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.373-374
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• 2000

• Korean Chemical Engineering Research
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• 제49권4호
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• pp.470-474
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• 2011

볏짚은 한국에서 매년 대량 생산되는 주요 작물이다. 침지공정을 이용한 목질계 바이오매스의 전처리는 대기압과 $60^{\circ}C$의 온도에서 온화한 조건에서 수행되었다. 본 연구에서는 전처리된 바이오매스의 효소당화 조건을 찾아보았다. 볏짚의 경우에 이전의 목질계 바이오매스와 비교하여 당화시간이 다른 것들보다 짧은 것으로 나타났다. SAA(Soaking in Aqueous Ammonia) 전처리 볏짚의 당화는 40~48시간 사이에 종료가 되었고 $50^{\circ}C$에서 높은 글루코스 전환율을 나타냈다. 글루코스 전환율은 효소사용량이 각각 65 FPU/ml과 32 CbU/ml일 때 높았다. 기질 농도가 5%(w/v)일 때 전환율은 72시간 동안 당화 후에 83.8%로 나타났다. SAA 전처리 볏짚의 동시당화발효(SSF; Simultaneous Saccharification and Fermentation) 실험에서는 $40^{\circ}C$에서 높은 에탄올 생산수율을 보였다. 그때의 수율은 48시간에서 33.05%로 나타났다.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.218-230
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• 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.