• 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.

• Korean Chemical Engineering Research
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• v.59 no.1
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• pp.54-59
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• 2021

The pretreatment of cellulosic biomass is essentially needed because it has more lignin compared with a starch biomass. Ethanol as an organosolv for pretreatment can easily separate some components which can inhibit enzymatic hydrolysis and be re-usuable by distillation. The flow-through process have some strength, separating components continuously, development for scale up. In this research, two-kinds (wheat straw, miscanthus) of biomass was pretreated for development of enzymatic hydrolysis by adoption of pretreatment process of corn stover.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.1-5
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• 2015

This study is to investigate the effect of torrefaction on enzymatic hydrolysis of lignocellulosic biomass for bio-ethanol production. As a pretreatment, the torrefaction of lignocellulosic biomass was conducted in temperature of $250{\sim}350^{\circ}C$ in the absence of oxygen. Tween-80, nonionic surfactant, was tested to enhance saccharification efficiency by coping with hydrophobicity resulted from torrefaction. As a result, the glucose production from enzymatic hydrolysis of biomass pretreated by torrefaction was greater than that obtained from the non-pretreated biomass. Sugar conversion was higher when the biomass was saccharified with addition of tween-80. It was found that torrefaction can be applied as a preptreatment for lignocellulosic biomass and tween-80 is needed to enhance its enzyme saccharification.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.303-307
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• 2013

This study compares the efficacy of soaking and percolation pretreatments with alkaline solutions for lignocellulosic biomass. Various biomass such as rice straw and barley were pretreated by soaking processes in various alkaline solutions including sodium hydroxide, potassium hydroxide, aqueous ammonia and sodium carbonate. The enzymatic digestibility of rice straw and barley that had been pretreated by soaking in aqueous ammonia was over 80%. Eucalyptus residue, Larix leptolepis and Pinus rigida exhibited relatively low enzymatic digestibility. Nevertheless, the enzymatic digestibility of pretreated eucalyptus residue was increased by five times compared to that of the initial biomass. And, the enzymatic digestibility of the percolation pretreated eucalyptus residue was increased 12 times.

• Korean Chemical Engineering Research
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• v.56 no.4
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• pp.441-446
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• 2018

Herbaceous biomass is easier at chemical conversion than woody biomass. However, pretreatment must be needed because it has substantially lignin. Organsolv is good at fractionation of enzymatic hydrolysis inhibitors such as lignin and it is reusable by distillation when it has low molecular weight. Flow-through process can prevent recondensation of fractionated components and easily separate liquid from the biomass. In this study, the pretreatment was performed for decreasing additional process by using ethanol without catalyst because this process has a lot of operation expense at bio-alcohol production process. Flow-through pretreatment was performed at $150{\sim}190^{\circ}C$ with 30~99.5 wt% ethanol during 20~60 minutes. Also the phsyco-chemical pretreatment was performed for decreasing reaction time and temperature.

• Journal of the Korean Wood Science and Technology
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• v.37 no.3
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• pp.274-286
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• 2009

Lignocellulosic biomass is the most abundant raw material for bioconversion in many country. However the high costs for pretreatment and enzymatic hydrolysis 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 intermediates 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 pretreatment with lignocellulosic biomass in bioethanol production process.

• Korean Chemical Engineering Research
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• v.48 no.6
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• pp.704-711
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• 2010

Lignocellulose ($2^{nd}$ generation) is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of agriculture residuals and nonedible crops biomass, e.q., rice straw and miscanthus sinensis, because of their several superior aspects as agriculture residual and nonedible crops biomass; low lignin, high contents of carbohydrates. In this article, as the basic study of AP(Ammonia Percolation), the properties and the optium conditions of process were established, and then the overall efficiency of AP was investigated. The important independent variables for AP process were selected as ammonia concentration, reaction temperature, and reaction time. The percolation condition for maximizing the content of cellulose, the enzymatic digestibility, and the lignin removal was optimized using RSM(Response Surface Methodology). The determined optimum condition is ammonia concentration; 11.27%, reaction temperature; $157.75^{\circ}C$, and reaction time; 10.01 min. The satisfying results were obtained under this optimized condition, that is, the results are as follows: cellulose content(relative); 39.98%, lignin content(relative); 8.01%, and enzymatic digestibility; 85.89%.

• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.806-811
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• 2016

Organosolv pretreatment is the process to frationation of lignocellulosic feedstocks to enhancement of enzymatic hydrolysis. This process has advantages that organic solvents are always easy to recover by distillation and recycled for pretreatment. The chemical recovery in organosolv pretreatment can isolate lignin as a solid material and carbohydrates as fermentable sugars. For the economic considerations, using of low-molecular-weight alcohols such as ethanol and methanol have been favored. When acid catalysts are added in organic solvent, the rate of delignification could be increased. Mineral acids (hydrochloric acid, sulfuric acid, and phosphoric acid) are good catalysts to accelerate delignification and xylan degradation. In this study, the biomass was pretreated using 40~50 wt% ethanol at $170{\sim}180^{\circ}C$ during 20~60 min. As a results, the enzymatic digestibility of 2-stage pretreatment of rigida using 50 wt% ethanol at $180^{\circ}C$ was 40.6% but that of 1-stage pretreatment was 55.4% on same conditions, therefore it is shown that the pretreatment using mixture of the organosolv and catalyst was effective than using them separately.

• Korean Chemical Engineering Research
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• v.49 no.3
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• pp.292-296
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• 2011

Liberation of fermentable sugars from lignocellulosic biomass is one of the key challenges in production of cellulosic ethanol. Aqueous ammonia cleaves ether and ester bonds in lignin carbohydrate complexes. It is an effective swelling reagent for lignocellulosic biomass. The aqueous ammonia pretreatment selectively reduces the lignin content of biomass. However, at high temperatures, this process solubilizes more than 50% of the hemicellulose in the biomass. Here we conducted a SAA(Soaking in Aqueous Ammonia) process by moderate reaction temperatures at atmospheric pressure using various lignocellulosicbiomass. The optimum condition of this process was 15 wt% of aqueous ammonia at 50 of reaction time during 72 hr. The delignification was up to 60% basis on initial biomass and the enzymatic digestibility was 60-90% for agricultural biomass, respectively.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.171-171
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• 2011

리그노셀룰로오스 바이오매스를 원료로 하여 발효당을 생산하고자 할 때 최종적인 당수율은 적용하는 전처리 기술의 종류와 전처리 조건에 따라 크게 달라질 수 있다는 사실은 널리 알려져 있다. 또한 전처리물의 효소당화에서 셀룰로오스의 당전환율은 효소의 종류와 사용량에 의존적이므로 부족한 전처리 효과를 일부 보완하기도 한다. 본 연구에서는 바이오매스의 효소당화에 흔히 사용되고 있는 특정효소와 최근 공급되기 시작한 새로운 효소를 시료로 하여 해바라기 줄기의 열수전처리에 이은 효소당화에서 효소의 종류가 최종 당수율, 효소당화 시간 및 전처리효과에 미치는 영향을 측정하였다. 해바라기 줄기 분말을 $180^{\circ}C$에서 30분 동안 열수전처리하였을 때 헤미셀룰로오스의 수율이 최대가 되었으나 이 조건에서는 후속 효소당화에 의한 포도당 수율이 높지 않았다. Celluclast 1.5L 혹은 Celluclast conc BG는 전처리 물의 당화속도가 상대적으로 빠른 편이었고, 이 효소에 의한 당수율은 해바라기 줄기 셀룰로오스 함량의 80% 내외였으며, 바이오매스 1g당 효소첨가량이 3ml까지 증가함에 따라 당수율도 꾸준히 증가하는 경향을 보였다. 반면에 노보자임 스코리아로부터 분양받은 효소로서 NS22074와 NS50010의 혼합물은 Celluclast보다 약 10% 더 높은 당수율을 보여주었으나 당화는 상대적으로 느리게 진행되어 72시간 이상이 소요되었다. Endoxylanase 혹은 hemicellulase 등 다른 효소를 NS22074와 NS50010의 혼합물에 가하여도 당수율의 증대 효과는 미미하거나 거의 없었다. 시험에 사용한 효소제제에는 포도당, 소르비톨 등 여러 가지 당들이 보존제 혹은 안정화제로 함유되어 있는 것으로 나타나서 사용에 주의할 필요가 이었다.