Benzene, Toluene, meta-Xylene의 혐기성 분해에 미치는 전자수용체와 시료 적응의 영향

윤인길,권오섭,김상진,Yoon, In-Kil,Kwon, O-Seob,Kim, Sang-Jin 한국미생물학회 1998 미생물학회지 Vol.34 No.3

연안 저서시료에 의한 benzene과 toluene, meta-xylene(BTX)의 혐기성 분해를 촉진시키기 위해 전자수용체 및 접종 시료의 적응에 따른 분해 정도를 조사하였다. 비적응 시료에 의해 BTX 는 10주 정도의 적응기 후에 분해되기 시작하여 16주 경과 후 benzene은 37~61%, toluene은 57~61% 분해되었다. 접종 시료별 혐기성 분해도는 유해물질의 유입이 많은 지역에서 채취한 시료가 우수한 분해력을 보였다. 그러나 6개월 가량 적응시킨 결과, 접종 시료별 BTX의 분해 차이는 나타나지 않았으며 적응기가 발생하지 않은 채 빨리 분해시켰다. BTX 단일 화합물을 첨가하였을 경우, 메탄생성 조건에서도 분해도가 다른 조건에 비해 다소 느리게 일어났으며, BTX 혼합체에서는 탈질화 조건에서 분해력이 다소 떨어졌다. BTX의 성분별 분해 정도는 m-xylene이 가장 빨랐으며, benzene의 분해가 가장 느렸다. 오랜 기간 BTX에 적응된 시료에 의해서도 m-xylene의 분해가 빨랐으나 benzene의 분해도 신속히 일어나 toluene과 비슷한 분해율을 나타냈다. 이러한 BTX의 혐기성 분해에 따라 독성이 감소하였다. The effects of electron acceptors and acclimation of inoculum on the anaerobic degradation of benzene, toluene, and m-xylene (BTX) were investigated to enhance the rate of degradation by estuarine sediment inoculum. With the fresh sediment inocula, degradation of BTX ensued after a 10-week acclimation period, and 37~61% of benzene and 57~61% of toluene were degraded after 16 weeks. Sediments from heavily contaminated sites showed higher degradation rates of BTX. After a 6-month of acclimation, degradation onset rapidly from the time of BTX addition and no difference was found among the sediment inocula. Single compound of BTX was slowly degraded in the methanogenic conditions, however, the degradation of BTX mixture was slow in the denitrifying conditions. Although the degradation rate of m-xylene was the fastest among the components of BTX mixture, longer acclimation enhanced the degradation rate of BTX, especially that of benzene. When the culture fluids were tested with Microtox, anaerobic degradation of BTX reduced the toxicity of BTX as well.

낙동강 하구 저질층에서의 혐기성 섬유소 분해에 관한 연구

윤인길,권오섭 ( In Kil Yoon,O Seob Kwon ) 한국하천호수학회 1995 생태와 환경 Vol.28 No.3

Environmental factors affecting on the anaerobic degradation of Phragmites longivalvis and cellulose films were investigated in the sediments of Naktong River Estuary. Dry weights of P. longivalvis were linearly decreased during the incubating periods(r^2> 0.90), but the contents of total nitrogen and total prosphorous were logarithmically decreased(r^2> 0.73). Though the differences of dry weight, total nitrogen, and total phosphorous among the investigated stations were not significant, in situ degradation rates of cellulose film were much different and the fastest was found in the sediments layer of Ulsukdo. Rising of water temperature activated the degradation rates of cellulose film. Anaerobic degradation rates using sulfate and carbonate were faster than those using nitrate as a terminal electron acceptor. Though addition of N and P did not significantly increased, addition of hydrogen gas in the head space of vials stimulated the anaerobic degradation of cellulose film. These results suggest that the P. longivalvis litters are slowly decomposed in the sediments and the degradation products could be a significant nutrient source in Naktong River Estuary. The anaerobic bacterial communities related to cellulose decomposition in the sediments layer of Naktong Estuary are not limited to N and P and can use various terminal electron acceptors.

회분식 배양에 의한 서낙동강 저서층의 영양염류 용출

김성한,윤인길,권오섭 ( Seong Han Kim,In Kil Yoon,O Seob Kwon ) 한국하천호수학회 1997 생태와 환경 Vol.30 No.3

Under the laboratory batch systems, we measured the nutrient release from the sediment of Seo-Naktong River to the overlying water. The concentration of NH_4+ in the water columns appeared the maximum at the beginning of incubation and decreased until 10-day incubation, and after that time the concentrations were relatively constant. The variation pattern of NO-3- was reversely matched with the pattern of NH_4+, and the maximum of PO-43- was detected at 24-day incubation. With this concentration changes of nutrients, NH_4+ release from the sediment layer to the water column of Seo-Naktong River was calculated as 53.9 mg-N/m^2/d, and PO_43- release as 5.3 mg-P/m^2/d. Considering the changes of nutrients, dissolved oxygen, and pH of water column and sediment porewater in the incubation chambers, and the field data of Seo-Naktong River, the mechanism of nutrient release in Naktong River was supposed that high concentrations of NH_4+ released are oxidized to NO-3- via nitrification, and the resulting anaerobic condition, especially in bottom layer of water column, stimulates the release of P0_43-.

낙동강 하구 저서층의 환경요인과 저서미생물의 분포

김성한,윤인길,송성주,김영의,권오섭 ( Seong Han Kim,In Kil Yoon,Seong Ju Song,Young Eui Kim,O Seob Kwon ) 한국하천호수학회 1996 생태와 환경 Vol.29 No.3

Depth profiles of physico-chemical parameters and distributions of benthic microorganisms were measured at the sediments of Ulsukdo, Naktong Estuary to identify the relatedness with the anaerobic degradation of sedimented organic matters. The organic contents, total nitrogen, and total phosphorous were decreased with increasing depth, but the patterns of inorganic nutrients of porewater showed no distinct profiles. Among inorganic sulfur compounds, the concentration of sulfide was varied with the depth. The observation that the highest cell numbers of total bacteria, heterotrophic bacteria, sulfur-oxidizing bacteria, anaerobic photosynthetic bacteria, and sulfate-reducing bacteria were found in the uppermost layer of the sediment was well coincided with the depth profiles of parameters of nutrient loading. At the upper layer of sediments, the density of methanogens was lower than that of sulfate-reducing bacteria, but at the lower layer, the former was higher. With this result, it could be supposed that at the upper sediments layer of Ulsukdo the fermentation products of organics were degraded mainly by sulfate-reducing bacteria but at the lower layer methanogens were the main degrading ones. Although the depth profiles of organic contents and sulfur bacteria had similar patterns, the distributions of inorganic sulfur compounds except sulfide were nearly constant and the cell numbers of sulfur bacteria were only a very few portions of total bacterial counts. These resulsts suggest that the effects of sulfur bacteria on the cycling of sedimented organics might be negligible at Ulsukdo of Naktong River Estuary.

단핵방향족 탄화수소의 혐기성 분해에 미치는 유기물 첨가의 영향

윤인길,권오섭 한국환경생물학회 1998 환경생물 : 환경생물학회지 Vol.16 No.4

유기물 첨가가 단핵방향족 탄화수소의 생물학적 분해에 미치는 영향을 파악하기 위하여 농축 배양된 혐기성 저서시료를 이용하여 조사하였다. Benzene과 toluene, m-xylene(BTX)을 150μM씩 첨가한 배지에 acetate, acetone 및 glucose를 각각 첨가하여 혐기성 상태에서 배양하였다. Benzene과 toluene, xylene은 유사한 화학 구조를 가지고 있지만, 각 BTX 화합물의 분해정도는 접종 시료와 기질에 따라 다르게 나타났다. 24주 배양 후 benzene은 26∼30%, toluene은 44∼52%, m-xylene은 65∼68%분해되었다. Benzene의 혐기성 분해는 acetate와 acetone을 처음 첨가하였을 때 억제되었으나 재투여 시에는 증가하였다. 24주 배양 후 acetate와 acetone을 첨가하였을 때보다 포도당을 첨가할 경우에 BTX의 분해력이 높게 나타났으며, BTX 혼합체를 재 투여하였을 때도 유사한 분해 경향을 보였다. 배양 초기 시료의 EC_50보다 10주 배양한 시료의 EC_50가 2∼3배 증가하여 혐기성 분해에 따라 BTX의 잔류독성이 감소하는 것으로 나타났다. The effects of different organic substrates on the abilities of anaerobic sediment inoculum to biodegradability of monoaromatic hydrocarbons were studied. Sediments collected from a site previously contaminated with benzene, toluene and m-xylene (BTX) were dosed with 150 M of BTX and incubated anaerobically with 2 mM of acetate, acetone, and glucose, respectively. Although BTX compounds have a similar chemical structure, the fates of individual BTX compound differed when the compounds were fed to mixed culture sediment slurries. After 24 weeks of incubation, the concentration of benzene, toluene, and m-xylene were reduced to 26∼30%, 44∼52%, and 65∼68% of the original concentrations. Degradation of benzene was inhibited by the first addition of substrates such as acetate and acetone. After 24 weeks incubation, however, the glucose-fed batches showed faster and more extensive degradation of BTX compounds than the acetate- or acetone-fed batches. These tendencies also appeared to occur with that of BTX mixtures and were repeated upon a second addition of BTX mixtures. EC_50 of 10-weeks incubating samples were two to three times greater than those of initial samples, which indicates that the toxicity of BTX was decreased during the anaerobic degradation.