• 태양에너지
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• 제18권3호
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• pp.161-167
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• 1998

석탄액화시 나무, 리그닌, 흑액 등 바이오매스계 첨가제의 효과를 실험식적 규모의 고온, 고압 반응기에서 고찰하였다. 석탄액화시 리그닌계의 첨가는 석탄의 분해를 돕고, 액체생성물의 질을 높여준다. $400^{\circ}C$에서는 나무를 첨가하게 되면, 액체생성물이 8%정도 증가하지만, 그이상의 온도에서는 기체생성물의 증가로 액체생성물 수율이 줄어든다. 흑액은 액화수율을 증대시키기는 하지만, 그 증가율은 NaOH만을 첨가시킨 경우보다 낮았으며, $OH^-$의 존재 때문에 흑액중의 리그닌이 주는 효과가 그리 크지 않은 것으로 보인다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.136-141
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• 2005

The capability of utilizing a TCA cycle intermediates as the sole carbon source by the multi-vitamin auxotrophic yeast Torulopsis glabrata CCTCC M202019 was demonstrated with plate count method. It is indicated that T. glabrata could grew on a medium with one of the TCA cycle intermediates as the sole carbon source, but more colonies were observed when glucose, acetate and one of the TCA cycle intermediates coexisted in the medium. Among the intermediates of the TCA cycle examined in this study, cell growth was improved by supplementing oxaloacetate. Further investigation showed that the presence of acetate was necessary when oxaloacetate was supplemented. By supplementing with 10 g/L of oxaloacetate in pyruvate batch fermentation, dry cell weight increased from 11.8 g/L to 13.6 g/L, and pyruvate productivity was enhanced from $0.96\;gL^{-1}h^{-1}\;to\;1.19 gL^{-1}h^{-1}$ after cultivation of 56 h. The yield of pyruvate to glucose was also improved from 0.63 g/g to 0.66 g/g. These results indicate that under vitamins limitation, the productivity and yield of pyruvate could be enhanced via an increase of cell growth by the supplementation of oxaloacetate.

• KSBB Journal
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• 제26권5호
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• pp.400-406
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• 2011

This study was investigated to improve the saccharification yield of Ulva pertusa Kjellman by the high pressure homogenization process. It was found that the high pressure homogenization pretreatment effectively destructed the cell wall structures only by using water. The high pressure homogenization process was operated under various conditions such as 10000, 20000 or 30000 psi with different recycling numbers. The optimal condition was determined as 30000 psi and 2 pass of recycling numbers and the sugar conversion yields were 16.02 (%, w/w) of glucose and 14.70 (%,w/w) of xylose, respectively. In the case of enzymatic treating the hydrolyzates with 5 FPU/glucan of celullase and 100 units/mL of amyloglucosidase, 65.8% of carbohydrates was converted into glucose. Using the hydrolysates of Ulva pertusa Kjellman, 48.7% of ethanol was obtained in the culture S.cerevisiae. These results showed that the high pressure homogenization process could efficiently hydrolyze the marine resource by using only water for bioethanol production.

• 한국가스학회지
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• 제20권6호
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• pp.95-101
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• 2016

본 연구에서는 다양한 수소 생산 방법 중 하나인 천연가스 수증기 개질반응(natural gas steam reforming reaction)에 대해 일반적인 충전층반응기와 반응기와 수소분리기가 결합된 새로운 형태의 분리막 반응기에서의 성능에 대한 비교분석을 수행하였다. Xu 와 Froment에 의해 기존에 발표된 실험결과를 바탕으로 상업용 화학공정모사기인 Aspen $HYSYS^{(R)}$ 모델이 개발되었으며, 반응온도, $H_2$ 투과량, Ar 유량 등이 분리막 반응기에서의 반응물의 전환율 및 $H_2$ 수율 향상도에 미치는 영향에 대해 분석한 결과 분리막 반응기에서 보다 많은 양의 수소수율 및 메탄전환율이 확인되었다. 더 나아가, 전체 시스템에서 필요로 하는 열량을 공급하기 위해 요구되는 천연가스의 양에 초점을 맞춰 분리막 반응기에서의 원가절감 가능성을 평가한 결과, 분리막 반응기에서 10.94%의 원가절감이 관찰되었다.

• 한국농공학회논문집
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• 제53권1호
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• pp.71-81
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• 2011

Due to increased human activities and intensive rainfall events in a watershed, soil erosion and sediment transport have been hot issues in many areas of the world. To evaluate soil erosion problems spatially and temporarily, many computer models have been developed and evaluated over the years. However, it would not be reasonable to apply the model to a watershed if topography and environment are different to some degrees. Also, source codes of these models are not always public for modification. The ArcGIS model builder provides ease-of-use interface to develop model by linking several processes and input/output data together. In addition, it would be much easier to modify/enhance the model developed by others. Thus, simple model was developed to decide soil erosion hot spot areas using ArcGIS model builder tool in this study. This tool was applied to a watershed to evaluate model performance. It was found that sediment yield was estimated to be 13.7 ton/ha/yr at the most severe soil erosion hot spot area in the study watershed. As shown in this study, the ArcGIS model builder is an efficient tool to develop simple models without professional programming abilities. The model, developed in this study, is available at http://www.EnvSys.co.kr/~sateec/toolbox for free download. This tool can be easily modified for further enhancement with simple operations within ArcGIS model builder interface. Although very simple soil erosion and sediment yield were developed using model builder and applied to study watershed for soil erosion hot spot area in this study. The approaches shown in this study provides insights for model development and code sharing for the researchers in the related areas.

• 한국미생물·생명공학회지
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• 제49권2호
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• pp.181-191
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• 2021

The present study addresses isolation, optimization, partial purification, and characterization of a haloalkaline serine protease from a newly isolated haloarchaeal strain isolated from Wadi El Natrun in Egypt. We expected that a two-step sequential statistical approach (one variable at a time, followed by response surface methodology) might maximize the production of the haloalkaline serine protease. The enzyme was partially purified using Hiprep 16/60 sephacryl S-100 HR gel filtration column. Molecular identification revealed the newly isolated haloarchaeon to be Natrialba hulunbeirensis strain WNHS14. Among several tested physicochemical determinants, casamino acids, KCl, and NaCl showed the most significant effects on enzyme production as determined from results of the One-Variable-At-A-time (OVAT) study. The BoxBehnken design localized the optimal levels of the three key determinants; casamino acids, KCl, and NaCl to be 0.5% (w/v), 0.02% (w/v), and 15% (w/v), respectively, obtaining 62.9 U/ml as the maximal amount of protease produced after treatment at 40℃, and pH 9 for 9 days with 6-fold enhancement in yield. The enzyme was partially purified after size exclusion chromatography with specific activity, purification fold, and yield of 1282.63 U/mg, 8.9, and 23%, respectively. The enzyme showed its maximal activity at pH, temperature, and NaCl concentration optima of 10, 75℃, and 2 M, respectively. Phenylmethylsulfonyl fluoride (PMSF, 5 mM) completely inhibited enzyme activity.

• 농업과학연구
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• 제45권4호
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• pp.601-614
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• 2018

Chitosan with a natural antimicrobial property has been introduced to protect horticultural crops from diseases as an environmentally friendly method. The purpose of this study was to investigate the effects of the pre-harvest application of chitosan on growth and quality during the late stage of fruit development and on the simulated marketing of the peach fruit (Prunus persica L.). The application of chitosan with calcium chloride ($100mg{\cdot}L^{-1}$) three times at one week intervals 4 weeks before the harvest significantly increased the fruit weight, changed the fruit shape, and reduced the fruit length/diameter ratio giving the peach fruits a round oblate shape. The calcium treatment contributed to enhancing or maintaining the storage potential by increasing the flesh firmness. However, at higher concentrations of $CaCl_2$, i.e., > $600mg{\cdot}L^{-1}$, the positive effects of the chitosan application were offset, and fruit growth was not affected by calcium alone. The application of the chitosan/calcium mixture delayed fruit softening; however, this effect was shortened when the storage temperature was $20^{\circ}C$ rather than $15^{\circ}C$. The internal quality of the fruit was profoundly affected by the concentration of calcium added to the chitosan, and delayed fruit maturation was observed at a higher concentration of calcium. The pre-harvest application of chitosan with calcium contributes to the enhancement of food safety by inhibiting the occurrence of diseases during postharvest handling. Considering the above results, chitosan has the potential to improve both the yield of peach fruits and their storability. Because chitosan can enhance the freshness and shelf-life of fresh produce, it is necessary to examine its effects on other horticultural crops.

• 한국잡초학회지
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• 제7권1호
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• pp.98-106
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• 1987

Carbofuran이 벼 생육(生育)에 미치는 영향을 알기 위해 1981년(年)부터 1986년(年)까지 영남작물시험장(嶺南作物試驗場)에서 벼종자(種子) 발아영향(發芽影響), 못자리 묘생육영향(苗生育影響), 본답(本畓) 벼생육영향(生育影響) 및 기상재해영향(氣象災害影響) 등(等)을 통(通)하여 구명(究明)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. Carbofuran 처리(處理)는 벼종자(種子) 발아(發芽)에 영향을 미쳤는데 지상부(地上部)보다 지하부(地下部)의 생육(生育)에 대한 영향이 컸다. carbofuran 농도(濃度)가 높아짐에 따라 전체종근수(全體種根數)는 감소(減少)되나 뿌리당(當) 길이는 50ppm까지 길어졌다. 2. 보온절충식(保溫折衷式)못자리에서의 carbofuran 처리(處理)는 무비구(無肥區)에서 3요소비료(要素肥料) 표준시용량(標準施用量) 정도(程度)의 생육(生育)까지 증진(增進)시켰고 또한 통일형(統一型) 품종(品種)의 적고피해(赤枯被害)를 회복(回復)시키는 효과(效果)가 있었는데 적고회복(赤枯回復) 요인(要因)으로는 파괴(破壞)된 엽록소(葉綠素) 자체(自體)의 회복(回復)이 아니라 묘생육량(苗生育量) 증대(增大)에 의한 것이었다. 그리고 carbofuran 처리시기효과(處理時期効果)에 있어서는 파종전(播種前) 처리(處理)가 가장 높고 다음으로는 vinyl 제거전(除去前), vinyl 제거후(除去後)의 순(順)이었다. 3. 본답(本畓)에서의 벼 벼생육증진효과(生育增進効果)는 이앙전(移秧前) 처리(處理)가 이앙(移秧) 25일(日) 후(後) 처리(處理) 보다 그리고 1 모작답(毛作畓)보다 2모작답(毛作畓)에서 높은 경향(傾向)이었고, 증진(增進)되는 생육형질(生育形質)로는 년차간(年次間) 및 품종간(品種間) 다소(多少) 차이(差異)가 있지만 간장(稈長), 수수(穗數), 영화수(穎花數) 및 추수력(抽穗力) 등(等)이었는데 그 중(中)에서도 수수증대(穗數增大) 요인(要因)이 가장 컸다. 4. Carbofuran 처리(處理)는 감수분열기(減數分裂期)와 출수기(出穗期)의 저온피해(低溫被害)와 침관수(浸冠水) 피해경감효과(被害輕減効果)가 있었으며 주요(主要) 생육증진요인(生育增進要因)으로는 임실비율(稔實比率), 등숙비율(登熟比率) 및 광합성능력증진(光合成能力增進)에 있었다.

• 한국토양비료학회지
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• 제33권6호
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• pp.493-497
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• 2000

제강슬래그의 밭작물 재배시 산성토양 개량제로서의 이용 가능성을 밝히기 위해 1997년에 공시품종을 은하콩으로 하여 나주시 남평의 전라남도 진흥원 실험답에 무처리, 제강슬래그 4, 8, $12Mg\;ha^{-1}$ 그리고 석회 $2Mg\;ha^{-1}$를 처리하여 콩을 재배하였다. 파종 15일 후부터 5회에 걸쳐 초장과 지상부 건물중 그리고 지상부 식물체의 무기화학성분 함량을 조사하였으며 매 조사시기 마다 토양 표본을 채취하여 토양의 주요 무기화학성분함량을 조사하였다. 수량 및 수량 구성요소를 조사하였고 또한 토양표본을 채취하여 무기화학성분을 측정하였다. 밭토양의 토양 pH, CEC, Ca, 그리고 Fe함량은 제강슬래그 시용 수준이 증가함에 따라 높아지는 경향이었다. 제강슬래그 8과 $12Mg\;ha^{-1}$ 처리는 무처리에 비해 유의하게 높은 pH를 보였는데 이는 제강슬래그 처리에 따른 토양 Ca함량의 증가에서 기인한 것으로 생각되며, Fe 함량도 제강슬래그 처리량이 증가할수록 높아지는 경향이었다. 석회 $2Mg\;ha^{-1}$ 처리구의 pH는 제강슬래그 4나 $8Mg\;ha^{-1}$의 그것과 비슷하여 이들 수준의 제강슬래그 처리에 의한 산성토양 개량효과는 석회 $2Mg\;ha^{-1}$ 처리와 비슷한 것으로 생각된다. 제강슬래그 시용에 따른 콩의 생육은 생육초기부터 무처리보다 양호하였고 생육후기에는 석회시용보다 더 효과적인 것으로 나타났다. 콩의 수량은 제강슬래그 $8Mg\;ha^{-1}$ 처리에서 $1,232kg\;ha^{-1}$로 가장 높았으며 이는 수량이 가장 낮은 무처리구의 $902kg\;ha^{-1}$에 비하여 $330kg\;ha^{-1}$ 높은 수준으로 37% 수량증가를 보였다. 이상의 결과로 보아 적정시용 수준은 $8Mg\;ha^{-1}$ 정도인 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.115-122
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• 1993

Poly(3-hydroxybutyrate)(P(3HB)) accumulation under nutrient-rich condition with various amounts of $(NH_4)_2 SO_4$ was systematically investigated. The results of the electron-microscopy and the solvent extraction showed that the P(3HB) accumulation is unavoidable even under nutrient-rich condition. This indicates that in a two-step culture of Alcaligenes eutrophus H16, the researches should be careful in interpreting the data of polyhydroxyalkanoates(PHAs) accumulation in terms of the carbon-source fed in the second step because the two-step culture product contains the P(3HB) produced under nutrient-rich condition. The polyester production capability in a two-step batch culture of A. eutrophus H16(ATCC 17699) was also investigated using various saccharides and their derivatives such as glucose, fructose, gluconic acid, glucaric acid, sorbitol, lactose, galactose, and mannose. The polyesters synthesized were characterized by 500 MHz$^{1}H-NMR$ spectroscopy, intrinsic viscosity$[\eta]$ measurement in chloroform and differential scanning calorimetry(DSC). 500 MHz $^{1}H-NMR$ analysis showed that all polyesters synthesized generally contained 1~2 mol% of 3HV. Another finding is that the glucose utilization can be increased by changing the autoclaving procedure of the substrate to enhance the P(3HB) production yield up to 46 wt% of P(3HB) in dry cells.