Streptomyces thermocyaneoviolaceus의 Xylanase 생산조건 및 Xylooligo당의 생산

주길재,박희동,최준호,이인구,이오석,권달호 慶北大學校農業科學技術硏究所 1998 慶北大農學誌 Vol.16 No.-

농산폐자원으로부터 기능성물질인 xylooligo당을 생산하기 위해서 내열성 균주인 S.thermocyaneoviolaceus가 생산하는 xylanase의 생산최적조건을 검토한 결과 0.8% 밀기울, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.005% FeSO₄·7H₂O, 0.05% KH₂PO₄및 0.2% K₂HPO₄를 함유한 배지(pH7.0)에서 50℃, 24시간 배양시 최고효소활성(2.47 unit/ml)의 배양상징액을 얻을 수 있었다. 효소의 최적반응조건은 pH5.5, 65℃였다. 또한 pH안정성을 조사한 결과 pH4.5∼9.5사이에서 4℃에서 12시간후에도 80% 이상의 효소활성을 유지하였고, 열 안정성은 60℃에서 1시간 처리후 94%이상의 효소활성을 유지하는 내열성이 있는 효소였다. 생산된 xylanase birchwood xylan 반응생성물을 TLC 및 HPLC로 확인해 본 결과, pH가 낮을수록(pH 5.0∼6.0) xylobiose와 xylotriose및 소량의 xylose의 양이 증가하였고, pH가 높을수록 (pH8.0∼9.0) X₄이상의 각종 xylooligo당의 양이 상대적으로 증가하였다. 또한 24 시간후에는 xylan의 상대량이 25% 이하로 감소하면서 주분해산물로 xylobiose가 생산되었으며 xylotriose와 xylose 및 X₄이상의 각종 xylooligo당이 생산되었다. A thermotolerant bacterium, Streptomyces thermocyaneoviolaceus which produced xylan-degrading enzymes, utilized excellently xylan of wheat bran by producing the enzymes in comparison with that of birchwood or oat spelts. Optimal enzyme production was achieved in WB medium containing 0.8% wheat bran, 0.06% yeast extract, 0.06% bactopeptone, 0.05% MgSO₄·7H₂O, 0.05% FeSO₄·7H₂O, 0.05% KH₂PO₄ and, 0.2% K₂HPO₄(pH 7.0) at 50℃ for 24 hrs. The optimal pH and temperature for the hydrolysis of xylan were pH 5.5 and 65℃, respectively. The enzyme activity was retained more than 80% at the range from pH 4.5 to pH 9.5 at 4℃ for 12 hrs and 94% on the heat-treatment at 65℃ for 1 hr. Xylobiose, xylotriose, xylose, and other xylooligosaccharides were produced as end products from hydrolysis of birchwood xylan by the xylanase of S. thermocyaneoviolceus.

Effect of Tween surfactant components for remediation of toluene-contaminated groundwater

Dal-Heui Lee,Eun-Sik Kim,Ho-Wan Chang 한국지질과학협의회 2005 Geosciences Journal Vol.9 No.3

The objectives of this study were to select potentiallysuitable surfactants that solubilize toluene present as a contami-nant and to determine the effectiveness of toluene removal fromgroundwater by the selected surfactants. Four different surfac-tants of Tween series were chosen based on surfactant types, tox-icity, HLB (Hydrophilic-Lipophilic Balance), CMC (Critical Micellewas not able to solubilize at least 1 mL of toluene and was con-sidered inefective. Tween 40, Tween 60 and Tween 80 were rela-tively good toluene solubilizers. The highest recovery (98%) of thetoluene was obtained using a nonionic surfactant (Twen 60) in thebatch experiments. In Tween series surfactant, the trend of ionicstrength magnitude in sampled groundwater was closely relatedwith that of recovery rates. The ionic strength of aqueous phasehad a strong efect in aqueous activity. The aqueous activity wasdecrease when ionic strength was incremployed may be useful for rapid selection of surfactants and areessential for reducing cost in surfactant-assisted remediation. Also,these selected surfactants are expected to be in practical use forremediation of toluene-contaminated groundwater.

Mixing effect of NaCl and surfactant on the remediation of TCB contaminated soil

Dal-Heui Lee,Ho-Wan Chang,Chul Kim 한국지질과학협의회 2008 Geosciences Journal Vol.12 No.1

In order to evaluate the mixing effect of NaCl andsurfactant on the remediation of TCB contaminated soil, columnexperiments were performed. Selected soils for this study were twoIowa field soils (Fruitfield, and Webster) and one Korea field soil(Pyeongtaek). We used four nontoxic, water-soluble anionic (DOSL,robenzene (TCB) was chosen as the model contaminant. Selectedelectrolyte for this study was NaCl. The TCB contaminated soilswere leached with surfactant solution of 4% (v/v) or 4% (w/v)with or without 5% (w/v) and 10% (w/v) NaCl. As controls, TCBcontaminated soils were also leached with deionized water. For thenonionic surfactants (POE20, POE4), the mixing effect of NaCl onthe solubilization of contaminant was insignificant. However, muchgreater mixing effectiveness was observed using anionic surfactant(SLS, single head structure) solutions containing electrolyte (NaCl)from two Iowa soils and one Korea soil. In contrast, anothering effectiveness on the solubilization of TCB from thre soils.However, the NaCl mixing effect of DOSL anionic surfactant wasfound after leaching of 2500 ml solution with Pyeongtaek soil. Theeffect of NaCl in changing efectiveness was due to Na+ (counter-ion) effects. The maximum recovery of added TCB in column testswas 97% for 4% (w/v) aqueous SLS anionic surfactant + 10% (w/v)NaCl. A little effectiveness of 4% (v/v) DOSL (anionic surfactant)with electrolytes may be due to small adsorption of the double-headshowed that the key factor in the variation of TCB removal effectdue to surfactant + NaCl leaching was not surfactant types butsurfactant structure. Also, results of this study sugest that theanionic surfactant (SLS) solutions containing electrolyte (NaCl) isa good candidate for surfactant-asisted remediation of TCB con-taminated soil.

The Effect of the Mixture of Nonionic Surfactant and Bioactive Agent for Surfactant-enhanced Soil Flushing (SESF) of TCB Contaminated Soil

Lee, Dal-Heui,Cho, Heuy Nam,Chung, Sung-Lae Korean Society of Soil and Groundwater Environment 2014 지하수토양환경 Vol.19 No.2

The objective of this study was to find the effect of the mixture of the nonionic surfactant and bioactive agent that solubilizes trichlorobenzene (TCB) present as a contaminant for surfactant-enhanced soil flushing (SESF). Three different nonionic surfactants and two different bioactive agents were obtained from four companies. Separate funnel experiments and shaker table agitation / centrifugation experiments were used for the test. Based on the separate funnel experimental results, three suitable mixture agents (APG + OSE, Brij 35 + MOSE, T-Maz 60 + MOSE) were selected. In the shaker table agitation / centrifugation experiments, these three different mixture agents were reduced to one (T-Maz 60 +MOSE). The maximum removal (95%) of TCB was obtained using a mixture of the nonionic surfactant and bioactive agent. Therefore, the used test methods and results can be used for SESF.

Comparison of pH and counter-ion effect in surfactant-assisted remediation

Dal-Heui Lee,류종식,김은식 한국지질과학협의회 2003 Geosciences Journal Vol.7 No.2

In order to determine whether pH or counter-ion ismore effective in modifying surfactant effectiveness, column exper-iments were performed. Otawa sand was selected for model soiland toluene was used as a model contaminant. DOSL (anionic sur-factant) was used for this study. The greatest recovery of toluenein column tests was 92%, which was obtained with a surfactant +NaOH. The effect of NaCl in changing effectiveness was less thanthat of NaOH. Much greater effectiveness was observed using sur-factant solutions containing NaOH. The effect of NaOH in chang-ing effectiveness was not due to Na+ effects, but to the OH- asshown by these experimental results. The effect of counter-ion(Na+) was small, and was much less than that of pH in surfactant-assisted remediation.

Rational surfactant selection and optimization of surfactant solution parameters for surfactant-enhanced soil washing (SESW) of industrially contaminated soils in Korea

Dal-Heui Lee,Eun-Sik Kim,Kyung-Yup Hwang,Ho-Wan Chang 대한지질학회 2004 대한지질학회 학술대회 Vol.2004 No.

Synergism effect of mixed surfactant solutions in remediation of soil contaminated with PCE

Dal-Heui Lee,Ho-Wan Chang,Robert D. Cody 한국지질과학협의회 2004 Geosciences Journal Vol.8 No.3

The purpose of this research was to evaluate theeffect of mixed surfactant solution for removal of perchloroethyl-ene (PCE) in sandy soil. Ten different surfactant solutions wereused in column studies. Mixed surfactant solutions (anionic andy worked in the sandy soil forremoval of PCE as a result of synergism between the two types ofsurfactants. The effectiveness of the mixture of surfactants [anionicDOSL (Diphenyl Oxide Disulfonates) and nonionic Tween 60] was3538% greater than that for the anionic or nonionic surfactantalone. However, synergism between the anionic SDS (SodiumN-dodecyl Sulfate) and the anionic DOSL was not observed. Causeof the lack of synerg two anionic surfactantsis uncertain but may result from the twin head structure of DOSL.The results indicate that mixed surfactant solution (1:1 mixture ofanionic and nonionic) leaching is a promising candidate for theremediation of PCE contaminated sandy soil.

구두발표 : 강우특성과 토양의 경사도가 토양침식량에 미치는 영향

이달희 ( Dal Heui Lee ),정교철 ( Gyo Cheol Jeong ) 대한지질공학회 2013 대한지질공학회 학술발표회논문집 Vol.2013 No.1

톨루엔으로 오염된 토양에서 DOSL 계면활성제를 이용한 최적의 정화 조건 규명

이달희,김동주,Robert D. Cody 한국지하수토양환경학회 2001 지하수토양환경 Vol.6 No.2

본 주상실험은 오염된 토양에서의 계면활성제 용액상태에 따른 복원 효과를 조사하기 위하여 실행되었다. 농도, pH, 온도, 그리고 용액의 유속을 달리하여 실험을 수행하였다. 실험에 사용된 오염물질은 톨루엔, 토양시료는 Iowa Fruitfield sandy soil, 그리고 계면활성제는 Sodium diphenyl oxide disulfonate(DOSL)이었다. 실험결과, 최적 조건은 다음과 같이 구해졌다. 계면활성제의 농도는 4%(v/v), pH는 10, 온도는 20℃, 그리고 유속은 4mL/min이었다. 이 조건이 모두 만족하는 상태에서는 95%의 톨루엔이 제거되었으며 이는 다른 조건에서보다 6∼19%의 상승효과를 보인 것이다. 본 실험에서 보여준 계면활성제 조건은 톨루엔으로 오염된 대수층의 복원에 매우 유용한 자료가 될 것이다. Column tests were carried out to examine the effect of surfactant solution conditions on the surfactant-enhanced remediation of soil columns contaminated by toluene. The conditioned parameters of the surfactant solution for the column tests were concentration, pH, temperature and flow rate. The test results revealed that an optimum condition was achieved for 4%(v/v) of concentration, 10 of pH, 20℃ of temperature and 4mL/min of flow rate respectively. The removal of 95% of toluene was obtained when optimal conditions of each surfactant solution parameter were simultaneously met. This was a marked improvement and removal efficiency increased by 6-19% compared to that with unadjusted conditions. The optimum range of these parameters may be useful for a surfactant-based remediation in the aquifer contaminated by toluene.

Remediation of Perchloroethylene Contaminated Groundwater by Permeable Reactive Barrier Using Iron, Granular Activated carbon, and Soil

Lee-Won Jeon,Dal-Heui Lee,Ho-Wan Chang 대한지질학회 2005 대한지질학회 학술대회 Vol.2005 No.