Airlift 생물 반응기의 설계

류희욱,장용근 한국미생물학회 1994 微生物과 産業 Vol.20 No.2

많은 산업용 ALB가 여러 발효공정에서 성공적으로 사용되고 있음에도 불구하고, 반응기의 설계를 위해 필요한 기본적인 지식들을 제공하는 자료는 그리 많지 않다. 본 총설에서는 ALB의 기본개념을 소개하고, ALB의 설계를 위해 이용가능한 기본적인 정보를 제시하고자 한다.

파일럿 규모 바이오필터를 이용한 정밀화학공장 배출가스의 처리

류희욱,이태호,박창호 경희대학교 산학협력기술연구원 2009 산학협력기술연구논문집 Vol.15 No.-

A pilot-plant biofilter packed with polyurethane foam was installed in an fine chemical plant emitting gas streams containing ethyl alcohol, ethyl acetate, and dichloromethane. The biofilter was successfully operated for 30 days under highly fluctuating incoming concentrations at a residence time of 36 and 60 sec. Both ethyl alcohol and ethyl acetate were removed more than 95%, but dichloromethane removal was less than 50%. Malodor was also removed more than 90% from 17 days after start up.

Air - lift 생물반응기를 이용한 하수 슬러지의 중금속 제거

류희욱,문희선,조경숙 대한환경공학회 1998 대한환경공학회 학술발표논문집 Vol.1998 No.12

철환원세균을 이용한 저품위 점토의 개량[I] : 전통적 수비법과 생물공학적 숙성법의 비교

류희욱,조경숙,김민주,강석영,최희락 한국생물공학회 2000 KSBB Journal Vol.15 No.2

전통적으로 사용되어 왔던 점토의 숙성과정을 과학적으로 규명하였고, 철환원세균의 농화배양액을 이용하는 생명공학기술을 이용한 개량된 점토 숙성방법을 연구하였다. 전통적으로 사용되어 왔던 수비법에 의한 점토의 숙성은 토착 미생물들이 점토에 함유된 유기물을 분해하는 과정에서 철불순물을 점토로부터 제거하여 색상을 향상시킬 뿐만 아니라 점토의 점성과 가소성 및 강도를 증진시키는 효과가 있음을 알 수 있었다. 점토숙성용 철환원세균 농화배양액을 얻는 방법을 제시하였고, 점토에 탄소원을 첨가한 후 혐기적 조건에서 농화배양액을 이용한 점토 숙성 방법을 제시하였다. 생물공학기술을 활용한 개량점토 숙성법은 전통적인 점토 숙성에서 소요되는 점토의 처리 시간을 약 1/6 수준이하로 단축시킬 수 있었고, 점토로부터 철불순물을 보다 효과적으로 제거할 수 있었을 뿐만 아니라 전통적인 방법보다도 물성이 우수한 점토로 고품위화가 가능하였다. The traditional ripening method of clay was analyzed. An advanced refining method of clay using enrichment cultures of iron r reducing bacteria was developed. After the traditional ripening, the whiteness of the clay was increased due to removal of | iron impurities by inhabitant dissilmaltien with iron reducing bacteria. Other characteristics of the refined clay such as v viscosity, plasticity, and strength were also improved by iron reducing bacteria. An advanced method of clay refinement with a anaerobic enrichment cultivation of iron reducing bacteria supplemented with an extra carbon source such as glucose was s suggested. When the clay was treated by the advanced method. the refinement time could be reduced to 1/6 of that r required by the traditional method. The physical properties of the refined clay by the advanced method were better than t those of the traditionally refined clay.

Acidithiobacillus ferrooxidans에 의한 생물학적 석탄탈황에 미치는 조업인자의 영향

류희욱 한국미생물·생명공학회 2003 한국미생물·생명공학회지 Vol.31 No.4

양돈시설 악취관리(3) : 악취 제어 기술

류희욱,조경숙,이태호,허목 한국냄새환경학회 2004 실내환경 및 냄새 학회지 Vol.3 No.1

Production of Polyhydroxyalkanoates by Azotobacter vinelandii UWD Using Swine Wastewater: Effect of Supplementing Glucose, Yeast Extract, and Inorganic Salts

류희욱,조경숙,Philip R. Goodrich,박창호 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.6

This study examined the effect of adding glucose, yeast extract, and inorganic salts to swine wastewater (SWW) in a batch culture on the production of a biodegradable plastic, polyhydroxyalkanoate (PHA). A bacterial strain, Azotobacter vinelandii UWD, was used to produce PHA without limiting the non-carbon nutrients. The addition of glucose (30 g/L) to the SWW medium increased the level of cell growth (4.4~7.0 times) and PHA production (3.8~8.5 times) depending upon the dilution of SWW. A 50% dilution of SWW was found to be optimal considering the dry cell weight (9.40 g/L), PHA content (58 wt%), and hydroxyvalerate (HV) mol fraction in the PHA (4.3 mol%). A 75% SWW medium was more advantageous for producing PHA with a higher HV fraction (7.1 mol%) at the expense of losing 22% of PHA production. The undiluted SWW medium produced less than one third of the PHA compared with the 50% SWW medium, but the HV fraction was the highest (10.8 mol%). Regarding the effect of the glucose concentration, at 20 g/L glucose, the dry cell weight and level of PHA production increased to 9.34 g/L (0.63 g PHA/g dry cell weight) and 5.90 g/L, respectively. At 50 g/L glucose, there was no significant increase in PHA production. For the glucose-supplemented (30 g/L) 50% SWW medium, the addition of a nitrogen source (1 g/L of yeast extract) did not increase the level of cell growth or PHA production because the C:N ratio (23:1) was already close to the optimal value (22:1). Better aeration increased the productivity of PHA. External nitrogen supplements (1 g/L of yeast extract) and other essential mineral salts was not necessary for bacterial growth because they were contained in the SWW. These results suggest that SWW is an excellent feedstock for producing larger amounts of the value-added material, PHA, if it is combined with carbohydrate-rich organic waste.

Toluene Degradation in a Polyurethane Biofilter at High Loading

류희욱,이태호,So Jong Kim,조경숙 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.3

In the present study, toluene elimination in the polyurethane (PU) biofilter during long-term (145 day) operation was characterized, and assessed the effects of changing the inlet loading and space velocity (SV). A very high elimination capacity of 3.7 kg•m-³•h-¹ was obtained at an inlet loading of 4.0 kg•m-³•h-¹ (inlet toluene concentration of 900 ppmv at a SV of 1,040 h-¹). Backwashing with irrigation and compressed air allowed maintenance of a pressure drop of < 80 mm H₂O•m-¹-filter at an SV of 830 h-¹ and an elimination efficiency of > 90% during the 145 day of operation. In conclusion, the PU biofilter can overcome the problems of clogging caused by excess biomass growth and of low treatment capacities of conventional biofilters.

Alcaligenes eutrophus의 배양액으로부터 균체 분리 효율에 미치는 철(Fe)계 응집제의 효과

류희욱,조경숙,곽종운,장용근 한국산업미생물학회 1998 한국미생물·생명공학회지 Vol.26 No.3

Alcaligenes eutrophus의 세포배양액(23-21Og dry weight/L)으로부터 균체 회수 효율에 미치는 철계 응집제 첨자 효과에 대해 연구하였다. 응집제로는 무기 응집제인 Fe_2(SO_4)_3과 무기 고분자 응집제인 Ferix-3를 사용하였다. 철계 응집제는 3-13의 넓은 pH 범위에서 응집효과를 나타내었으며, 배양액의 pH가 증가할수록 floc의 크기는 증가하였다. 균체 회수를 위한 배양액의 최적 pH는 10-13이었다. 최적 응집제의 첨가량은 세포농도가 증가함에 따라 증가하였는데, 무기응집제인 Fe_2(SO_4)_3보다는 무기고분자응집제인 Ferix-3이 적은 농도에서 응집효율이 우수함을 알 수 있었다. 210 g/L의 세포농도 배양액에 Ferix-3을 1300 mg Fe/L를 첨가하면 45×g의 낮은 원심력에 의해 95% 이상의 균체를 회수 가능하였다. 응집제의 요구량은 배양액 중의 NH^+_4, 농도에 비례하여 증가하였고, 배양액 중의 NH^+_4 농도가 1 g 증가하면 응집제가 0.066 g Fe^3+ 정도 더 요구되었다. Alcaligenes eutrophus was successfully recovered from high cell density broth by pre-treatment with Fe-based coagulants. An inorganic coagulant, Fe_2(SO_4)_3, and a polymerized coagulant, Ferix-3, were used. Good coagulation was observed in broad pH range of 3 to 13, the floc size was increased with increasing pH of culture broth. The optimum pH of fermentation broth for cell recovery was 10 to 13. The optimum coagulant dosages to recover cells with 95% cell recovery were increased with increasing cell concentration. Optimal coagulant dosage was lower when the polymerized coagulant was used rather than the inorganic coagulant. The coexistence of NH^+_4 was increased coagulant requirement, and the coagulant requirement was 0.066g Fe^3+/g NH^+_4.

Fatty acid methyl ester profiles을 이용한 고온 바이오필터 미생물 군집 분석

류희욱,조경숙 한국냄새환경학회 2004 실내환경 및 냄새 학회지 Vol.3 No.4

To monitor the variations of microbial communities with the operation periods in a thermo-biofilter for the treatment of hot BTX gases, Fatty Acid Methyl Ester (FAME) profiles of the microbial communities have been analyzed using the MIDI system. The relative contents of C8:0 and C16:0 among the fatty acids analyzed in the inoculum sample were 13.6 and 18.5%, respectively. The relative contents of these fatty acids were also maintained in the biofilter samples after operation for 40 days. The content of C16:0 2OH in the inoculum sample was about 24%, but was reduced to 1.0-2.7% in the biofilter samples. In contrast to C16:0 2OH, the contents of C18:0 increased to 25.2-27.7% from 13.5%. The dominant fatty acid in the microbial community of the biofilter was changed from C16:0 2OH to C18:0 during operating of the biofilter. The increase of a long chain saturated fatty acid such as C18:0 indicated that the microbial community in the thermo-biofilter for hot BTX gases became dominated with theromophilic microorganisms. BTX 고온 가스 제거용 바이오필터의 조업조건에 따른 바이오필터의 미생물 군집 변화를 모니터링하기 위해 균체의 FAME profile을 MIDI 방법에 의해 분석하였다. 바이오필터에 접종한 종균 시료에서 C8:0과 C16:0 지방산이 차지하는 비율은 각각 13.6% 및 18.5% 이었다. 조업과정에서도 바이오필터에 서식하는 미생물 균체의 지방산 중 C8:0과 C16:0 지방산 비율은 종균과 거의 동일하게 유지되었다. 그러나, C16:0 2OH 지방산은 종균 시료에서는 약 24% 이었으나, 바이오필터 조업과정에서 이 지방산이 차지하는 비율은 1.0-2.7%로 크게 감소하였다. 이와는 대조적으로, 종균 시료에서 C18:0 지방산이 차지하는 비율은 13.5%이었으나, 바이오필터 조업과정에서는 이 지방산의 비율이 25.2-27.7%로 거의 2배 증가하였다. 즉, 바이오필터 운전 과정에서 우점 지방산이 C16:0 2OH에서 C18:0로 교체되었는데, C18:0 지방산과 같은 탄소수가 긴 포화 지방산 비율의 증가는 고온 BTX 바이오필터에 고온균이 우점화되어 감을 시사한다.