• KSBB Journal
• /
• 제25권6호
• /
• pp.547-552
• /
• 2010

The recent bloom of a very large jellyfish Nemopilema nomurai has caused a danger to sea fishery and sea bathers. Presently, Nemopilema nomurai is thrown away through a separator system in the sea. The objective of this work was to produce bio-gas from Nemopilema nomurai by using anaerobic digestion. The bio-gas includes the hydrogen or the methane gases. It relates that Nemopilema nomurai is effectually changed into the renewable energy. When the jellyfish biomass was used as an organic carbon source the bio-gases were evolved. The aim of this study was to determine the optimal conditions for hydrogen and methane gases production according to the substrate concentrations of Nemopilema nomurai, optimal culture condition and the sludge-pretreatment without pH control. The optimal culture condition was found to be $35^{\circ}C$ and the heat-treatments of jellyfish was done at $120^{\circ}C$ for 30 min. The production rate of hydrogen and methane gas were found to be 8.8 mL/L/h, 37.2 mL/L/h from 1.5 g of dry Nemopilema nomurai.

• 대한치과의사협회지
• /
• 제23권2호통권189호
• /
• pp.121-127
• /
• 1985

• 유기물자원화
• /
• 제11권1호
• /
• pp.70-76
• /
• 2003

소화슬러지를 열처리한 혼합 배양 미생물을 식종균으로, 자당을 기질로 사용하는 혐기성 수소 생산 공정을 운전하면서 pH 조절, 반복 열처리, 기질 농도 변화 등을 통해 지속적인 수소 생산 방법을 고찰하였다. 유입 기질의 농도가 5g COD/L인 경우 운전 초기에는 $0.5mole\;H_2/mole\;hexose$ 이상의 수소가 발생하지만 9일 이상 지속되지 못하였다. 이러한 현상의 원인은 수소 생성균이 공정 내에서 고농도로 존재하지 못하기 때문인 것으로 판단되며 pH를 5.3으로 유지하는 것만으로는 극복될 수 없었다. 반복 열처리를 적용할 경우 별도의 식종균 재주입 없이 효율이 감소된 수소 생성 공정을 원상태로 복구할 수 있음을 확인할 수 있었으나, 수소 생성 효율이 시간에 따라 감소하므로 열처리를 자주 해야 하는 문제가 발생했다. 유입 기질의 농도가 30g COD/L인 경우에는 24일간 지속적인 수소 생성이 가능하였으며, CSTR의 경우 $1.0-1.4mole\;H_2/mole\;hexose$, ASBR의 경우에는 $0.2-0.3mole\;H_2/mole\;hexose$의 생성 효율을 보였다. 수소 생성 시 유출수 내 용존성 유기물의 90% 이상은 유기산이었으며 그 중 n-butyrate가 가장 많은 양을 차지하였다.

• Asian-Australasian Journal of Animal Sciences
• /
• 제12권5호
• /
• pp.752-757
• /
• 1999

Studies were made of digestion of timothy (Pheleum pretense) hay, tall fescue (Festuca elatior) hay, and rice (Oryza sativa) straw in pure cultures of rumen anaerobic fungus, Neocallimastix frontails MCH3. The fungus was inoculated on ground forages (1%, w/v) in an anaerobic medium and incubated at $39^{\circ}C$. Incubation was continued for 24, 48, 72 and 96 h. The losses of dry matter, xylose and glucose of forage during incubation were determined at the end of these incubation periods. Xylose and glucose were considered to be released from xylan and cellulose, respectively. The digested xylan to digested cellulose (X/C) ratios of the substrate were calculated. Xylanase and carboxymethyl cellulose (CMCase) of culture supernatant and residual substrate was measured at the same time. The X/C ratios in the cultures on timothy hay and rice straw were greater than 0.5 in the first 24-h incubation period. The values were smaller than 0.3 in tall fesque. The ratio of xylanase activity to that of CMCase in the first 24-h incubation period correlated well with the traits in X/C ratio. However xylanase activity was still superior to CMCase in the following incubation period (48 to 96 h), although the glucose (designated as cellulose) was more intensively digested than xylose (designated as xylan). The production of these polysaccharidases appeared to correlate with substrate cell-wall sugar composition, xylose to glucose ratios, at the beginning of fast growing period.

• Asian-Australasian Journal of Animal Sciences
• /
• 제20권1호
• /
• pp.70-74
• /
• 2007

An in vitro study was carried out to investigate the differences in rumen microbes and fiber degradation capacity between sheep and goats. Three local male sheep and three Inner Mongolia male cashmere goats (aged 1.5 to 2 years; weight 25.0 to 32.0 kg) were each fitted with a permanent rumen cannula used to provide rumen fluid. Cycloheximide was used to eliminate rumen anaerobic fungi. The results showed that the quantities of fungal zoospores in the culture fluid of the control group were significantly greater in the sheep than in the goats; however, bacteria and protozoa counts were significantly higher in goats than in sheep. The digestibility of straw dry matter did not differ significantly between the two species before elimination of fungi, but tended to be higher for sheep (55.4%) than for goats (53.3%). The results also indicated that bacteria counts increased significantly after elimination of anaerobic fungi; however, the digestibility of straw dry matter significantly decreased by 12.1% and 8.6% for sheep and goats respectively. This indicated that the anaerobic fungi of the rumen played an important role in degradation of fiber.

• 한국물환경학회지
• /
• 제24권3호
• /
• pp.306-310
• /
• 2008

Characteristics of microalgal growth was investigated using anaerobic effluent from two-phase animal waste digestor as substrate. Batch experiments were carried out to investigate the effect of the initial nitrogen and phosphorus concentrations on growth of Microcystis aeruginosa, Chlorella sp. and Euglena gracilis. In 400 times diluted anaerobic effluent (TN 3 mg/L), single cell growth of the Euglena gracilis population increased twice without delay, although Chlorella sp. and Microcystis aerugenos take over 144 hours. Similar appearance with single cell growth was observed in mixed cultures. However, microalgae population did not increase under condition of 10 times diluted influent (TP 3 mg/L) in both pure and mixed cultures, which was affected by high organic and nitrogen concentration. Logistic growth model successfully fitted to determine biokinetic parameters such as ${\lambda}$: lag time, ${\mu}m$: maximal specific growth rate, A: asymptote of growth.

• Journal of Microbiology
• /
• 제43권1호
• /
• pp.28-33
• /
• 2005

The purpose of this study was to develop a multipurpose incubator, without the gas cylinders (bottles) which are required for $H_2$ and $CO_2$ supplementation. In our bottle-free multipurpose incubator, the $H_2$ and $CO_2$ were generated by chemical reactions induced within the chamber. The reaction between sodium borohydride and acetic acid at a molar ratio of 1:1 was used to generate $H_2$, according to the following formula: $4NaBH_4+2CH_3COOH+7H_2O{\rightarrow} 2CH_3COONa+Na_2B_4O_7+16H_2$, whereas the other reaction, citric acid and sodium bicarbonate at a 1:1 molar ratio, was used to generate $CO_2$, according to the following formula: $C_6H_8O_7+3NaHCO_3{\rightarrow}Na_3(C_6H_5O_7)+3H_2O+3CO_2$. Five species of obligate anaerobic bacteria, one strain of capnophilic bacterium, and one strain of microaerophilic bacterium were successfully cultured in the presence of their respective suitable conditions, all of which were successfully generated by our bottle-free multipurpose incubator. We conclude that, due to its greater safety, versatility, and significantly lower operating costs, this bottle-free multipurpose incubator can be used for the production of fastidious bacterial cultures, and constitutes a favorable step above existing anaerobic incubators.

• Journal of Microbiology
• /
• 제37권4호
• /
• pp.206-212
• /
• 1999

In order to isolate a Fe(III)-reducer from the natural environment, soil samples were collected from various patty fields and enriched with ferric citrate as a source of Fe(III) under anaerobic condition. Since the enrichment culture was serially performed, the Fe(III)-reduction activity was serially diluted and cultivated on an agar plate containing lactate and ferric citrate in an anaerobic glove box. A Gram negative, motile, rod-shaped and facultative anaerobic Fe(III)-reducer was isolated based on its highest Fe(III)-reduction activity, Bacterial growth was coupled with oxidation of lactate to Fe(III)-reduction, but the isolate fermented pyruvate without Fe(III), The isolate reduced an insoluble ferric iron (FeOOH) as well as a soluble ferric iron (ferric citrate). Using the BBL crystal enteric/non-fermentor identification kit and 16S rDNA sequence analysis, the isolate was identified as Shewanella putrefaciens IR-1.

• 대한환경공학회지
• /
• 제22권10호
• /
• pp.1869-1879
• /
• 2000

혐기성 소화공정 중 생성되는 주요 중간대사산물인 프로피온산의 분해대사에 대한 연구중 에탄올과의 산화 환원 반응인 coupling 반응으로써 혐기성 소화공정에서 프로피온산 축적을 저감시킬 수 있는 연구를 수행하였다. 따라서, 본 연구는 혐기성 공정에서 프로피온산의 전환에 따른 동력학적 반응과 에탄올과의 상호 반응에 따른 특정기질 선호영향을 모델에 적용하여 살펴보았다. 본 연구는 4단계의 실험으로 수행되었다. 1, 2, 3단계는 각기 다른 기질에 순화된 미생물들을 이용하여 프로피온산 1 g COD/L와 에탄올의 농도를 각각 0, 100, 200, 400과 1,000 mg/L로 주입하여 프로피온산과 에탄올의 혐기성 분해과정을 비교 연구하였으며, 4단계에서는 Glu-MCR과 HPr-MCR의 순화미생물의 혼합비를 조절하여 프로피온산 1 g COD/L를 주입하였을 때의 혐기성 분해를 연구하였다. 본 연구에서는 수정된 경쟁적 모델을 이용하여 특정기질 선호현상을 규명하였고, 에탄올 농도의 증가에 따라 아세트산 형성반응의 $K_{s2}$값의 증가와 메탄화 과정에서의 아세트산 생성 및 분해과정에 해당되는 $K_3$값이 일부 증가하는 결과를 얻을 수 있었다. 또한 순화미생물들에 따라 프로피온산과 에탄올의 분해에 미치는 영향이 다른 결과를 얻을 수 있었다.

• Journal of Microbiology and Biotechnology
• /
• 제13권3호
• /
• pp.366-372
• /
• 2003

The production of microbiologically enriched cultures that degrade cis- 1,2-dichloroethylene(DCE) under anaerobic conditions was investigated. Among 80 environmental samples, 19 displayed significant degradation of $10{\mu}M$ cis-DCE during 1 month of anaerobic incubation, and one sediment sample collected at a landfill area (Nanji-do, Seoul, Korea) showed the greatest degradation ($94\%$). When this sediment culture was subcultured repeatedly, the ability to degrade cis-DCE gradually decreased. However, under Fe(III)-reducing conditions, cis-DCE degradation by the subculture was found to be maintained effectively. In the Fe(III)-reducing subculture, vinyl chloride (VC) was also degraded at the same extent as cis-DCE No accumulation of VC during the cis-DCE degradation was observed. Thus, Fe(III)-reducing microbes might be involved in the anaerobic degradation of the chlorinated ethenes. However, the subcultures established with Fe(III) could function even in the absence of Fe(III), showing that the degradation of cis-DCE and VC was not directly coupled with the Fe(III) reduction. Consequently, the two series of enrichment cultures could not be obtained that degrade both cis-DCE and VC in the presence or absence of Fe(III). Considering the lack of VC accumulation, both cultures reported herein may involve interesting mechanism(s) for the microbial remediation of environments contaminated with chlorinated ethenes. A number of fermentative reducers (microbes) which are known to reduce Fe(III) during their anaerobic growth are potential candidates involved in cir-DCE degradation in the presence and absence of Fe(III).