• 펄프종이기술
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• 제43권1호
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• pp.83-91
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• 2011

Hemicelluloses are useful materials for papermaking and other biotechnological applications. To recover and further utilize the hemicelluloses, this study carried out the pre-extraction of the hemicelluloses from Korean mixed hardwoods chips using hot water and sodium hydroxide solution at various temperature and time conditions. Through the hot water pre-extraction, the wood components of 22% was extracted and the 35% of the hemicelluloses which were contained in the original wood chips were dissolved into the pre-extractives. The yield of the pre-extractives was more significantly influenced by the pre-extraction temperature than the time. The pre-extractives with the yield of 30% could be obtained by alkali pre-extraction and alkali concentration was the most important factor. It had lower hemicellulose content but high molecular weight, compared with the hot water pre-extractives.

• Journal of Applied Biological Chemistry
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• 제56권3호
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• pp.171-177
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• 2013

Efficient extraction of total proteins from soil microorganisms is tedious because of small quantity. In this regard, an improved method for extraction of whole cell proteins is developed from soil microorganisms, Saccharomyces cerevisiae and Pichia pastoris. of which the cell wall are very strong. Pretreatment with NH4OH prior to the final extraction using NaOH/SDS was tried under the basis that ammonium ion was possible to enhance the permeability and/or to weaken the yeast cell walls. The pre-treatment of yeast cells with NH4OH drastically enhanced the protein extraction when it was compared with control (without NH4OH pre-treatment). At the pre-treatment of 0.04 N NH4OH at pH 9.0, about 3 fold of proteins was obtained from p. pastoris. Ammonium hydroxide appears to penetrate into the yeast cell walls more readily at basic pH. The effect of NH4OH pretreatment was pH dependent. The methods developed in this experiment might be applicable for an effective extraction of yeast proteins for the purpose of biochemical studies, especially proteomic analysis.

• KSBB Journal
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• 제25권4호
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• pp.371-378
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• 2010

For the biodiesel fuel production from microalgae, the lipid from wet and dry samples of green algae Scenedesmus sp. was extracted by using various solvents and pre-treatment methods. Extraction yield of the lyophilized sample was better than that of dry sample. Chloroform/methanol (2:1, v/v) and ultrasonication or homogenization method were also selected as the most effective solvent and pre-treatment methods for lipid extraction, respectively. Under these constraint conditions, optimization experiment of lipid extraction was investigated by Taguchi approach using orthogonal matrix $L_9$ ($3^4$) method. The optimum extraction conditions of lipid extraction was obtained at pre-treatment of homogenization, extraction time of 5 hour, temperature of $35^{\circ}C$, and solvent ratio of 1:20 (w/v). Yield of extraction at optimized condition was 20.55% and it was 96% of total lipid content (21.38%) of Scenedesmus sp.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권3호
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• pp.771-791
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• 2022

Protein-protein interaction (PPI) extraction from original text is important for revealing the molecular mechanism of biological processes. With the rapid growth of biomedical literature, manually extracting PPI has become more time-consuming and laborious. Therefore, the automatic PPI extraction from the raw literature through natural language processing technology has attracted the attention of the majority of researchers. We propose a PPI extraction model based on the large pre-trained language model and adversarial training. It enhances the learning of semantic and syntactic features using BioBERT pre-trained weights, which are built on large-scale domain corpora, and adversarial perturbations are applied to the embedding layer to improve the robustness of the model. Experimental results showed that the proposed model achieved the highest F1 scores (83.93% and 90.31%) on two corpora with large sample sizes, namely, AIMed and BioInfer, respectively, compared with the previous method. It also achieved comparable performance on three corpora with small sample sizes, namely, HPRD50, IEPA, and LLL.

• Korean Chemical Engineering Research
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• 제51권5호
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• pp.561-567
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• 2013

본 연구에서는 바이오연료 생산을 위한 헤미셀룰로오스의 회수 목적으로 혼합 하드우드 칩을 크라프트(kraft) 펄핑공정 전에 녹액(green liquor)으로 선-펄핑추출(pre-pulping extraction) 하였다. 본 실험에 사용된 녹액은 황화나트륨과 탄산나트륨이 주요 성분이며, 이 녹액에 목재 건조 질량당 0, 1, 3, 5%의 알칼리($Na_2O$)를 각각 충진하였다. 가혹 조건에 따른 선-펄핑추출액의 구성 성분을 알아보기 위해 추출은 반응시간은 1~2 h로 달리하면서 $160^{\circ}C$ 조건에서 실험을 수행하였다. 선-펄핑추출공정은 헤미셀룰로오스 추출시간과 녹액 주입 정도의 가혹도(severity)에 따라서 하향류 공정(downstream process)에서 활용 가능한 아세트산(acetic acid)과 단당류 농도, 그리고 유기산과 퓨란(furan)과 같은 분해 생성물의 축적 정도가 변한다. 본 연구 결과에서는 알칼리 주입 양이 증가할수록 헤미셀룰로오스에 존재하는 아세테이트(acetate)의 곁사슬과 용해성 및 리그닌의 양은 증가하지만, 추출액에서 탄수화물과 당류는 상당히 감소하였다. 특히 고온수(hot water)로 추출(알칼리 주입 0%)하는 경우 29.80 g/L 이상의 가장 많은 양의 탄수화물이 추출되었으나, 펄프 수율은 가장 많이 감소하였다. 또한 3% 녹액의 추출은 펄프 수율은 증가하였으나 당은 7.08 g/L로 많은 양이 감소하였다. 이 논문에서 얻어진 데이터를 통해 크라프트 펄핑공정에 추출공정 통합을 위한 헤미셀룰로오스 추출 조건을 최적화할 수 있을 것이다.

• 한국환경과학회지
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• 제28권11호
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• pp.927-933
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• 2019

A lipid-enriched strain of Botryococcus braunii (UTEX 572) was cultivated in a semi-batch aeration tank to enhance biomass as well as to develop intracellular lipids and fatty acids. A 30 day period of incubation produced 1.39 g/L of biomass and 0.31 g/L of total lipids in the biomass. The grown biomass was pre-treated using several methods to extract the total lipid content efficiently: ultrasonication was found to yield the highest percentage of lipids-namely 19.8% per biomass. Direct heating of biomass in an autoclave also showed better performance than when using only conventional solvent extraction. To enhance the biomass harvest and lipid extraction efficiency, coagulation and flocculation steps were added to the extraction process. It is noteworthy that not only the solvent type but also the solvent/biomass ratio greatly affected efficiency. In addition, the moisture content of the harvested(wet) biomass affected the efficiency significantly. This study elucidated the need for future research on optimizing this extraction process.

• 한국물환경학회지
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• 제32권6호
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• pp.600-627
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• 2016

Korea is one of the countries with a large veterinary antibiotics market, although antimicrobial resistance in bacteria is becoming a serious issue in many countries. The Korean government started to take interest in estimating the effects of livestock manure on rivers and agricultural soils and in monitoring of heavy metals, organic pollutants and antibiotics in the ambient water and soil. In this paper, pre-treatment methods to separate the selected antibiotics from solid samples were reviewed. It is essential to select an efficient and appropriate procedure for pre-treatment due to the high proportion of proteins and organics in biosolid samples. Pre-treatment consists of extraction followed by clean-up. Initially, homogenized samples were extracted by sonication, mechanical agitation or pressurized liquid extraction with methanol/acetonitrile/water mixture under acidic/basic conditions depending on the compound. However, aminoglycosides and colistin were extracted with 5% trichloroacetic acid and HCl, respectively. Since the ${\beta}-lactams$ are easily decomposed in acidic and basic conditions, they were extracted in neutral pH. Filtration with a membrane (pore size, $0.2{\mu}m$) or solid phase extraction with HLB and methanol, as eluents, was normally applied for the clean-up. At least, three different pre-treatment procedures should be adopted to screen all the selected antibiotics in solid samples.

• Journal of the Korean Wood Science and Technology
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• 제41권5호
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• pp.447-455
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• 2013

Hemicellulose extract obtained by pre-pulping extraction of woodchips, is very diluted acidic in nature. The major component responsible for this weak acidity is acetic acid, present in levels up to 5~10 g/L. Here, we report an exploratory study on the extract upgrading by reactive solvent extraction of acetic acid as well as ASPEN simulation. In this study, liquid-liquid equilibria for the ternary systems (water + acetic acid + ethyl acetate) were measured at the temperature of 298.15 K and 10 (pH = 2.02), 5 (pH = 2.17), and 1 (pH = 2.48) percent of acetic acid samples were used to carry out liquid-liquid extraction studies using ethyl acetate. In a one-stage batch experiment, 96.0% of acetic acid could be extracted for the solvent when the ratio of organic-to-aqueous phases is 4:1. For simulation results, they were used to estimate the interaction parameters between each of the three compounds of the systems studied for the NRTL and UNIQUAC models. The estimated interaction parameters were successfully used to predict the equilibrium compositions by the two models.

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2330-2334
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• 2013

A highly selective molecularly imprinted polymer (MIP) for sarcosine, a cancer marker, was prepared and its use as solid-phase extraction (SPE) sorbent material was demonstrated. The MIP was prepared by a very simple procedure using methacrylic acid as functional monomer and a mixture acetonitrile/water (4/1, v/v) as porogen, overcoming in this way the problems usually related to the imprinting of biological polar compounds. The MIP was tested in batch experiments in order to evaluate its binding properties and then used as SPE sorbent for the selective clean-up and pre-concentration of sarcosine. The extraction protocol was successfully applied to the direct extraction of sarcosine from spiked human urine indicating that the MIP allowed sarcosine to be pre-concentrated while simultaneously interfering compounds were removed from the matrix.

• Bulletin of the Korean Chemical Society
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• 제32권8호
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• pp.2637-2642
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• 2011

A new ultrasonic-assisted micellar extraction and cloud-point pre-concentration method was developed for the determination of major saikosaponins, namely saikosaponins -A, -C and -D, in Radix Bupleuri by high performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD). The non-ionic surfactant Genapol X-080 (oligoethylene glycol monoalkyl ether) was chosen as the extraction additive and parameters affecting the extraction efficiency were optimized. The highest yield was obtained with 10% (w/v) Genapol X-080, a liquid/solid ratio of 200:1 (mL/g) and ultrasonic-assisted extraction for 40 min. In addition, the optimum cloud-point pre-concentration was reached with 10% sodium sulfate and equilibration at $60^{\circ}C$ for 30 min. Separation was achieved on an Ascentis Express C18 column (100 ${\times}$ 4.6 mm i.d., 2.7 ${\mu}M$) using a binary mobile phase composed of 0.1% acetic acid and acetonitrile. Saikosaponins were detected by ELSD, which was operated at a $50^{\circ}C$ drift tube temperature and 3.0 bar nebulizer gas ($N_2$) pressure. The water-based solvent modified with Genapol X-080 showed better extraction efficiency compared to that of the conventional solvent methanol. Recovery of saikosaponins ranged from 93.1 to 101.9%. An environmentally-friendly extraction method was successfully applied to extract and enrich major saikosaponins in Radix Bupleuri.