Seasonal and Spatial Distribution of Trichoderma species in Forest Soils of Mt. Geryongsan

이영하,홍순우,Rhee, Young-Ha,Hong, Soon-Woo The Microbiological Society of Korea 1984 미생물학회지 Vol.22 No.3

Seasonal and spatial variations in propagule numbers of Trichoderma species were investigated every other month for one year in deciduous and coniferous forest soils and evaluated the relationships of Trichoderma spp. populations to soil environmental factors. The total population of Trichoderma spp. increased until summer and then declined until winter. The yearly mean frequency of Trichoderma spp. exceeded 1.4% of total fungal propagules in two sites. Decreases of absolute an relative propagule numbers of Trichoderma spp. with increasing soil depth were found and variation in Trichoderma spp. propagules caused by differences in soil depth ($0{\sim}50cm$) was greater than that caused by differences in sampling time. The most common species occurring in two sites was T. viride, followed by T. polysporum, T. koningii, and T. hamatum. Individual species of Trichoderma showed diferent abundance trend in accordance with sampling time. T. viride was dorminant from spring to autumn, while T. polysporum dominated over the other speicies in winter. Variations in propagule number of Trichoderma sppp. were principally mediated by the actions of biotic environmental factors rather than by the direct effects of abiotic factors. In multiple-regression analyses, 48% of the total vaiation in Trichoderma spp. propagules in deciduous site could be accounted for by total fungal propagules and soil CMCase actvity. In coniferous site, 65% of total variation could be accounted for by total fungal and bacterial propagules, moisture content and organic carbon content.

화학물질의 생분해성 측정을 위한 OECD 시험법의 평가

김하강(Ha Kang Kim),김균(Kyun Kim),김용화(Yong Hwa Kim),이영하(Young Ha Rhee) 한국환경생물학회 1999 환경생물 : 환경생물학회지 Vol.17 No.2

The efficiency of the OECD MITI(Ⅰ) test which is designated as a standard method for measuring the biodegradability of chemicals by the Korean Ministry of Environment was evaluated and compared with those of two other OECD ready biodegradability test : the manometric respirometry test and the closed bottle test. All the tests were applicable to a wide variety of organic chemicals and there were no significant differences in biodegradation rates of eight test chemicals and a reference chemical with three methods. However, the MITI(Ⅰ) test had unnecessary expense and complexity in preparation of a mixed inoculum. Decrease in bacterial diversity during pre-conditioning of the inoculum for 1 month was observed and therefore the mixed inoculum did not ensure the presence of a variety of species in the test. Based on the simplicity, cost-effectiveness and reproducibility of the test procedure, it is considered that the manometric respirometry test is the most adequate method which can replace the MITI(Ⅰ) test method.

계피로부터 항진균물질 AF-001 의 분리 정제 및 특성

방규호,이영하,민병선 ( Kyu Ho Bang,Young Ha Rhee,Byung Sun Min ) 한국균학회 1997 韓國菌學會誌 Vol.25 No.4

호알카리성 Cephalosporium sp. RYM202 로부터 분리된 alkaline xylanase ( CX-3) 의 작용 양상 및 화학적 변환

강명규,맹필재,이영하 ( Myoung Kyu Kang,Pil Jae Maeng,Young Ha Rhee ) 한국균학회 1996 韓國菌學會誌 Vol.24 No.4

Pseudomonas aeruginosa P-5에 존재하는 polyhydroxyalkanoate synthase PhaC1과 PhaC2의 기질특이성

우상희,이선희,이영하,Woo, Sang Hee,Lee, Sun Hee,Rhee, Young Ha 한국미생물학회 2016 미생물학회지 Vol.52 No.4

Pseudomonas aeruginosa P-5 균주는 홀수개의 탄소수를 갖는 지방산으로부터 3-hydroxyvalerate (3HV)와 medium-chain-length (MCL) 3-hydroxyalkanoates (3HAs) 단위체로 구성된 popolyhydroxyalkanoate (PHA) 공중합체를 생산하는 특이한 성질을 갖고 있다. 이 균주가 갖고 있는 2개의 MCL-PHA synthases ($PhaC1_{P-5}$와 $PhaC2_{P-5}$)의 탄소길이에 따른 기질특이성을 비교하기 위하여 각각의 유전자를 PHA 생합성능이 결여된 돌연변이주 Pseudomonas putida GPp104에 도입하고 발현시킨 결과, $PhaC2_{P-5}$는 3HV와 MCL 3HAs로 이루어진 공중합체를 생산하지만 $PhaC1_{P-5}$는 단지 MCL 3HAs로 구성된 공중합체를 생산하였다. 이는 $PhaC2_{P-5}$가 $PhaC1_{P-5}$과는 달리 보다 짧은 탄소길이의 3-hydroxyvaleryl Co-A를 기질로 인지하여 합성반응에 이용할 수 있음을 보여주는 것이다. 또한 $PhaC2_{P-5}$의 효소활성 및 기질특이성의 변화를 유도하기 위하여 위치지정 돌연변이생성을 수행하고 P. putida GPp104과 다른 PHA 생합성능 결여 돌연변이주인 Ralstonia eutropha $PHB^-4$에서 발현시킨 결과, $PhaC2_{P-5}$ 내 두 개 아미노산의 치환(Ser326Thr과 Gln482Lys)이 공중합체의 3HV 함량을 크게 증진시키는 효과를 보였다. 두 개 아미노산이 모두 치환된 $PhaC2_{P-5}$ 유전자($phaC2_{P-5}QKST$)를 갖는 P. putida GPp104를 nonanoic acid가 탄소원으로 함유된 배지에서 배양하였을 때, 모균주에 비해 공중합체 함량과 공중합체 내 3HV 함량이 각각 2.5배 및 3.5배 증가하였다. 따라서 $phaC2_{P-5}QKST$를 포함하는 재조합 균주는 개량된 물성의 신규PHAs 생산에 유용할 것으로 기대된다. Pseudomonas aeruginosa P-5 is an unusual organism capable of synthesizing polyhydroxyalkanoates (PHAs) consisting of 3-hydroxyvalerate (3HV) and medium-chain-length (MCL) 3-hydroxyalkanoate (3HA) monomer units when C-odd alkanoic acids are fed as the sole carbon source. Evaluation of the substrate chain-length specificity of two P. aeruginosa P-5 PHA synthases ($PhaC1_{P-5}$ and $PhaC2_{P-5}$) by heterologous expression of $PhaC1_{P-5}$ and $PhaC2_{P-5}$ genes in Pseudomonas putida GPp104 revealed that $PhaC2_{P-5}$ incorporates both 3HV and MCL 3HAs into PHA, whereas $PhaC1_{P-5}$ favors only MCL 3HAs for polymerization. In order to obtain $PhaC2_{P-5}$ mutants with altered substrate specificity, site-specific mutagenesis for $PhaC2_{P-5}$ was conducted. Amino acid substitutions of $PhaC2_{P-5}$ at two positions (Ser326Thr and Gln482Lys) were very effective for synthesizing copolymers with a higher 3HV fraction. When recombinant P. putida GPp104 harboring double mutated $phaC2_{P-5}$ gene ($phaC2_{P-5}QKST$) was grown on nonanoic acid, 2.5-fold increase of copolymer content with 3.8-fold increase of 3HV fraction was observed. The $phaC2_{P-5}QKST$-containing Ralstonia eutropha PHB-4 supplemented with valeric acid also produced copolymers consisting of 3HV and 3-hydroxyheptanoate with a high 3HV fraction. These results suggest that recombinants containing $phaC2_{P-5}QKST$ could be useful for production of new PHA copolymers with improved material properties.

호알카리성 Cephalosporium sp. RYM-202 의 회분 및 유가배양에 의한 Alkaline Carboxymethyl Cellulase 와 Xylanase 의 생산

강명규,김도영,이영하 ( Myoung Kyu Kang,Do Young Kim,Young Ha Rhee ) 한국균학회 1997 韓國菌學會誌 Vol.25 No.2

Aspergillus nidulans 에서의 핵전이에 의한 종내잡종 형성

양영기,박열,이영하,맹필재 ( Young Ki Yang,Yeol Park,Young Ha Rhee,Pil Jae Maeng ) 한국균학회 1989 韓國菌學會誌 Vol.17 No.3

호알칼리성 Cephaloporium sp. RYM-202 가 생산하는 carboxymethyl cellulase 의 부분정제 및 특성

강명규,박희문,이영하,김윤석,김여경 ( Myoung Kyu Kang,Hee Moon Park,Young Ha Rhee,Yun Seog Kim,Yeo Kyung Kim ) 한국균학회 1993 韓國菌學會誌 Vol.21 No.4

Saccharomyces cerevisiae Hansen CBS5926의 고농도 배양 및 동결건조 보존

방규호,김갑진,오덕환,이영하,Bang, Kyu-Ho,Kim, Gap-Jin,Oh, Deok-Hwan,Rhee, Young-Ha 한국미생물학회 1999 미생물학회지 Vol.35 No.4

정장용 효모로 알려져 있는 Saccharomyces cerevisiae Hansen CBS5926의 생균제 제조를 목적으로 생균수 증대를 위한 배양조건과 배양 후 얻은 균체의 효과적인 동결건조 보존법에 관하여 조사하였다. 포도당을 탄소원으로 하는 회분식과 유가식 배양에 비해 에탄올을 탄소원으로 하는 유가식 배양이 장점이 많은 것으로 나타났으며, 배양 72시간 후 2.2${\times}$10^9 cfu/ml의 생균수와 38g/l의 건조 균체량을 얻을 수 있었다. 에탄올을 탄소원으로 하는 유가식 배양으로부터 얻은 균체의 동결보존을 위한 보호제의 효능을 비교한 결과, 20% 백당(w/v)과 30% 유당(w/v)에서의 생존율이 16.3%로서 비교된 다른 종류의 동결보호제보다 효과적인 것으로 나타났다. 그러나, 백당, 유당 및 탈지분유의 혼합에 의한 동해방지 보호 효과를 비교한 결과 생존율이 12.4~16.5%로서 보호제의 혼합에 따른 생존율의 상승효과는 나타나지 않았다. Production of biomass by fed-batch culture of Saccharomyces cerevisiae Hansen CBS5926, which is used to treat intestinal disorders, was investigated using ethanol as the sole carbon source. Ethanol was a better carbon source than glucose for high cell density culture of the st-rain since it could decrease the frequency of contamination while increasing the efficiency and final productivity of the fermentation process. Under optimal conditions, 38 g/ℓ of dry cell weight with $2.2{\times}10^{9}$ cfu/㎖ of maximum viable cell count was achieved after 72h cultivation. Freeze-drying of the cultured yeast cells resulted in severe reduction of viability. Of the freeze-drying protectants tested, 20% sucrose and 30% lactose were most effective for the preservation of yeast cells with a viability level of 16.3%. A combination of skim milk and lactose with 20% sucrose(w/v) exerted no synergistic influence upo the viability of the cells during cryopreservation by freeze-drying.

혼합미생물배양체를 이용한 폐활성슬러지 가용화 산물로부터 polyhydroxyalkanoate 생합성

박태준,유영재,정동훈,이선희,이영하,Park, Taejun,Yoo, Young Jae,Jung, Dong Hoon,Lee, Sun Hee,Rhee, Young Ha 한국미생물학회 2017 미생물학회지 Vol.53 No.3

SA-TSA 복합구를 이용해 폐활성슬러지로부터 VFAs를 생산하고, 이를 발효 기질로 이용해 PHA를 생산하기 위한 실험을 수행하였다. 30%의 SA-TSA 복합구를 처리하였을 때 폐활성슬러지의 가용화 효율이 가장 효과적으로 일어나서 약 3,900 mg/L의 SCOD값을 얻었으며, acetic acid, propionic acid, iso-butyric acid 및 butyric acid를 주성분으로 하는 2,961 mg/L 농도의 VFAs를 얻었다. VFAs를 외부탄소원으로 이용하는 SBR 공정을 통해 PHA를 생합성하는 미생물을 농화배양하는 실험을 수행하고 PCR-DGGE로 분석한 결과, 우점 미생물로 Vibrio spp.와 Corynebacterium glutamicum이 확인되었다. 폐활성슬러지로부터 얻은 VFAs를 탄소원으로 사용하여 농화된 혼합미생물배양체를 회분배양한 결과, 건체량의 25.9%에 달하는 PHB를 얻었다. 본 연구결과는 SA-TSA 복합구를 이용하여 폐활성슬러지로부터 VFAs를 얻음으로써 폐슬러지 감량화 효과를 얻고, 또 혼합미생물배양체를 이용하여 VFAs를 바이오폴리머로 전환함으로써 경제성을 확보할 수 있는 새로운 생물공정의 가능성을 보여준다. A new approach to the solubilization of waste activated sludge (WAS) using alginate-quaternary ammonium complex beads was investigated under controlled mild alkaline conditions. The complex beads were prepared by the reaction of sodium alginate (SA) with 3-(trimethoxysilyl)propyl-octadecyldimethylammonium chloride (TSA) in acid solution, followed by crosslinking with $CaCl_2$. Treatment of WAS with SA-TSA complex beads was effective for enhancing the efficacy of WAS solubilization. The highest value of soluble chemical oxygen demand (SCOD) concentration (3,900 mg/L) was achieved after 10 days of treatment with 30% (v/v) SA-TSA complex beads. The WAS solubilization efficacy of the complex beads was also evaluated by estimating the concentrations of volatile fatty acids (VFAs). The maximum value of VFAs was 2,961 mg/L, and the overall proportions of VFAs were more than 75% of SCOD. The main components of VFAs were acetic, propionic, iso-butyric, and butyric acids. These results suggest that SA-TSA complex beads might be useful for enhancing the solubilization of WAS. The potential use of VFAs as the external carbon substrate for the production of polyhydroxyalkanoate (PHA) by a mixed microbial culture (MMC) was also examined. The enrichment of PHA-accumulating MMC could be achieved by periodic feeding of VFAs generated from WAS in a sequencing batch reactor. The composition of PHA synthesized from VFAs mainly consisted of 3-hydroxybutyrate. The maximum PHA content accounted for 25.9% of dry cell weight. PHA production by this process is considered to be promising since it has a doubly beneficial effect on the environment by reducing the amount of WAS and concomitantly producing an eco-friendly biopolymer.