• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.241-252
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• 2016

Cellulose acetate is one of well-known industrial materials which have various commercial uses. We treated the lignocellulosic biomass using two-step (steam explosion-chemical) reaction followed by acetylation to get the cellulose acetate in this study. The two-step treatment was done to improve the yields of acetylation of the substrates. The yields of the cellulose acetate were about 88.4, 88.1, and 151.7% in barley straw, rice straw, and oak tree, respectively. Also the degree of substitution (DS) of the acetates was 2.1 to 2.5 in the biomass. We found that the biomass were valuable cellulosic sources, including their derivatives, in this study. This means that the biomass can be converted into the high-valued cellulosic stuff.

• Mycobiology
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• 제44권1호
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• pp.48-53
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• 2016

Lenzites betulinus, known as gilled polypore belongs to Basidiomycota was isolated from fruiting body on broadleaf dead trees. It was found that the mycelia of white rot fungus Lenzites betulinus IUM 5468 produced ethanol from various sugars, including glucose, mannose, galactose, and cellobiose with a yield of 0.38, 0.26, 0.07, and 0.26 g of ethanol per gram of sugar consumed, respectively. This fungus relatively exhibited a good ethanol production from xylose at 0.26 g of ethanol per gram of sugar consumed. However, the ethanol conversion rate of arabinose was relatively low (at 0.07 g of ethanol per gram sugar). L. betulinus was capable of producing ethanol directly from rice straw and corn stalks at 0.22 g and 0.16 g of ethanol per gram of substrates, respectively, when this fungus was cultured in a basal medium containing 20 g/L rice straw or corn stalks. These results indicate that L. betulinus can produce ethanol efficiently from glucose, mannose, and cellobiose and produce ethanol very poorly from galactose and arabinose. Therefore, it is suggested that this fungus can ferment ethanol from various sugars and hydrolyze cellulosic materials to sugars and convert them to ethanol simultaneously.

• Korean Chemical Engineering Research
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• 제49권3호
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• pp.292-296
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• 2011

섬유소계 바이오매스의 전처리를 위한 암모니아수에 의한 침지공정(SAA; Soaking in Aqueous Ammonia)은 낮은 온도와 낮은 압력의 조건에서 수행하는 전처리 공정으로 고온고압이 필요로 하는 다른 전처리방법에 비해 그에 대한 비용을 절감할 수 있다는 장점이 있다. 본 연구에서는 다양한 바이오매스를 SAA공정에 적용시켜 그 특성을 보고자 한다. 실험을 행한 전처리 공정의 온도, 반응시간 그리고 암모니아수의 농도는 각각 $50{^{\circ}C}$, 72시간 그리고 15 wt%이다. 전처리 공정에 의해 초본계열은 탈리그닌이 초기 성분에 대해 60%로 되었고 전처리 전의 10-20%에 불과하던 당전환율이 전처리 후에 60-90%의 당전환율로 약 80%가 향상된 것으로 나타났지만 목본계열의 리그닌 성분은 10%정도만 제거되었고 당전환율은 전처리하지 않는 것과 별다른 차이를 보이지 않았다.

• Journal of Plant Biotechnology
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• 제34권2호
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• pp.111-118
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• 2007

가속도가 붙은 지구온난화 문제와 수 십년 이내로 예상되는 화석연료의 고갈은 지속가능하면서도 환경친화적인 새로운 형태의 에너지 출현을 필요로 하고 있다. 이러한 추세에 맞추어 태양광, 조력, 지열, 풍력, 수소 에너지와 더불어 바이오에너지가 대체에너지로서 주목받고 있다. 바이오에너지는 태양에너지를 유기물로 변환하는 식물을 재료로 하여 바이오 에탄올이나 바이오디젤 등을 생산하여 사용하는 것으로 대체 에너지가 갖춰야 할 조건을 두루 갖춘 최적의 신재생에너지로 고려되고 있다. 하지만 바이오에너지가 진정한 의미에서의 환경친화적이면서 지속가능성을 갖추기 위해서는 아직 기술적으로 해결해야할 문제점들이 많다. 최근 미국에서 바이오에탄올 생산을 위한 옥수수 소비량이 늘어 곡물 및 사료 가격의 급등 현상으로 이어지고 있다. 또한 이러한 현상은 개발도상국 식량자원의 선진국 유입 등으로 빈곤의 심화 등이 새로운 문제점으로 지적되고 있다. 따라서 곡물이 아닌 비식용 부위를 이용한 에탄올 생산이 대안으로 여겨지고 있는 바 셀룰로스 에탄올은 이러한 문제점을 극복할 수 있는 대체에너지로서 자리매김하고 있다. 셀룰로스 바이오에탄올은 사람 등의 동물이 소화하지 못하는 바이오매스의 대부분을 차지하는 식물 세포벽을 곰팡이 등에서 분리한 효소로 분해한 후 여기서 생성되는 당을 발효과정을 통해 생산되는 에탄올로서 전술한 바와 같은 문제점을 해결할 수 있는 유망한 대안 에너지로 고려되고 있다.

• Carbon letters
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• 제17권1호
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• pp.1-10
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• 2016

Lignocellulosic biomass conversion to biofuels such as ethanol and other value-added bio-products including activated carbons has attracted much attention. The development of an efficient, cost-effective, and eco-friendly pretreatment process is a major challenge in lignocellulosic biomass to biofuel conversion. Although several modern pretreatment technologies have been introduced, few promising technologies have been reported. Microwave irradiation or microwave-assisted methods (physical and chemical) for pretreatment (disintegration) of biomass have been gaining popularity over the last few years owing to their high heating efficiency, lower energy requirements, and easy operation. Acid and alkali pretreatments assisted by microwave heating meanwhile have been widely used for different types of lignocellulosic biomass conversion. Additional advantages of microwave-based pretreatments include faster treatment time, selective processing, instantaneous control, and acceleration of the reaction rate. The present review provides insights into the current research and advantages of using microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to fermentable sugars in the process of cellulosic ethanol production.

• Journal of Forest and Environmental Science
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• 제27권3호
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• pp.183-194
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• 2011

This study reviewed on the research trend of sources and utilization of the byproducts(Lignin) from bioethanol production process with lignocellulosic biomass such as wood, agri-processing by-products(corn fiber, sugarcane bagasse etc.) and energy crops(switch grass, poplar, Miscanthus etc.). During biochemical conversion process, only Cellulose and hemicellulosic fractions are converted into fermentable sugar, but lignin which represents the third largest fraction of lignocellulosic biomass is not convertible into fermentable sugars. It is therefore extremely important to recover and convert biomass-derived Lignin into high-value products to maintain economic competitiveness of cellulosic ethanol processes. It was introduced that lignin types and characteristics were different from various isolation methods and biomass sources. Also utilization and potentiality for market of those were discussed.

• Journal of the Korean Wood Science and Technology
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• 제17권2호
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• pp.65-73
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• 1989

Steam explosion process is an efficient pretreatment method for sparating and utilizing wood main components has attracted attention in utilization of ligno-cellulosic biomass. In order to obtain the effective pretreatment condition. this study was made explosion apparatus. examined the composition. extraction of exploded wood. Wood chips of pine(Pinus densiflora oak (Quercus serrata) and birch wood (Belula platyphylla var. japonica) were treated with a high pressure steam(20-30 kg/$cm^2$, 2-6 minutes). The results can be summarized as follow; In analysis of exploded wood(EXW). It was found arabinose residues rapidly decreased with increasing of steaming time and pressure. Extractives of EXW with sodium hydroxide increased with increasing of steaming-time and- pressure especially extractives 1% sodium hydroxide has higher than other extracted method extractives of hard wood(oak, birch) has higher than pine wood. In EXW extracted with sodium hydroxide and methanol lignin was partially delignified alkali extraction was more delignified than methanol extraction hardwood than pine wood.

• Asian-Australasian Journal of Animal Sciences
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• 제14권6호
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• pp.862-879
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• 2001

The walls of all higher plants are organized as a cellulosic, fibrillar phase embedded in a matrix phase composed of non-cellulosic polysaccharides, some proteins and, in most secondary walls, lignin. At the effective utilization of plant biomass, qualitative and quantitative analyses of plant cell walls are essential. Structural features of individual components are being clarified using newly developed equipments and techniques. However, "empirical" procedures to elucidate plant cell walls, which are not due to scientific definition of components, are still applied in some fields. These procedures may give misunderstanding for the effective utilization of plant biomass. In addition, interesting the investigation of wall organization is moving towards not only qualitatively characterisation, but also quantitation of the associations between wall components. These involve polysaccharide-polysaccharide and polysaccharide-lignin cross-links. Investigation of the associations is being done in order to understand the chemical structure, organization and biosynthesis of the cell wall and physiology of the plants. Procedures for qualitative and quantitative analyses based on the definition of cell wall components are reviewed focussing in nutritional elucidation of forage grasses by ruminant microorganisms.

• 펄프종이기술
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• 제29권4호
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• pp.18-27
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• 1997

This study was performed to obtained the optimal delignified condition of exploded wood on the acid hydrolysis with sulfuric acid. Wood chips of pine wood(Pinus desiflora), oak wood(Quercus serrata) and birch wood (Betula platyphylla var. japonica) were treated with a high pressure steam (20-30kgf/$\textrm{cm}^2$, 2-6 minutes). The exploded wood was delignified with sodium hydroxide and sodium chlorite, and then hydrolyzed with sulfuric acid. The result can be summerized as follows ; In the exploded wood treated with sodium hydroxide, the optimal concentration of sodium hydroxide was 1% as content of lignin in the exploded wood. Lignin content of exploded wood treated with sodium chlorite was lower then that sodium hydroxide. The maximum reducing sugar yield of exploded wood treated with 1% sodium hydroxide was lower than non-treated exploded wood. In the case of sodium chlorite treated, the maximum reducing sugar yield was hgher than non-treated exploded wood. Sugar composition of acid hydrolysis solution was composed of xylose and glucose residue, and the rate of glucose residue was increased in high pressure condition.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.179.1-179.1
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• 2011

Pretreatment of cellulosic biomass is necessary before enzymatic saccharification and fermentation. The objective of this study was to evaluate the effect of combined aqueous ammonia-dilute sulfuric acid treatment on cellulosic biomass. Miscanthus was pretreated using aqueous ammonia and dilute sulfuric acid solution under high temperature and pressure conditions to be converted into bioethanol. Aqueous ammonia treatment was performed with 15 %(w/w) ammonia solution at $150^{\circ}C$ of reaction temperature and 20 minutes of reaction time. And then, dilute sulfuric acid treatment was performed with 1.0 %(w/w) sulfuric acid solution at $150^{\circ}C$ of reaction temperature and 10 minutes of reaction time. The compositional variations of this combined aqueous ammonia-dilute sulfuric acid treatment resulted in 68.0 % of cellulose recovery and 95.7 % of hemicellulose, 81.3 % of lignin, 89.1 % of ash removal respectively. The enzymatic digestibility of 90.5 % was recorded in the combined pretreated Miscanthus sample and it was 14.7 times higher than the untreated sample. The ethanol yield in the Simultaneous Saccharification and Fermentation was 90.4 % of maximum theoretical yield based on cellulose content of the combined pretreated sample and it was about 98 % compared to the ${\alpha}$-cellulose ethanol yield.