• International journal of advanced smart convergence
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• 제5권2호
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• pp.18-23
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• 2016

Cell walls of microalgae consist of a polysaccharide and glycoprotein matrix providing the cells with a formidable defense against its environment. Anaerobic digestion (AD) of microalgae is primarily inhibited by the chemical composition of their cell walls containing biopolymers able to resist bacterial degradation. Adoption of pre-treatments such as thermal, thermal hydrolysis, ultrasound and enzymatic hydrolysis have the potential to remove these inhibitory compounds and enhance biogas yields by degrading the cell wall, and releasing the intracellular algogenic organic matter (AOM). This paper preproposal stage investigated the effect of different pre-treatments on microalgae cell wall, and their impact on the quantity of soluble biomass released in the media and thus on the digestion process yields. This Paper present optimum approach to degradation of the cell wall by ultra-sonication with practical design specification parameter for ultrasound based pretreatment system. As a result of this paper presents, a microalgae system in a wastewater treatment flowsheet for residual nutrient uptake can be justified by processing the waste biomass for energy recovery. As a conclusion on this result, Low energy harvesting technologies and pre-treatment of the algal biomass are required to improve the overall energy balance of this integrated system.

• 미생물학회지
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• 제37권3호
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• pp.209-213
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• 2001

Bacillus spp. 이용하여 B3공법을 사용하는 하수 종말 처리장의 포기조에서 Bacillus sup. 변화를 FSIH방법과 포자염색 방법으로 관찰하였다. DAPI로 측정한 세균수는 $3.2{\times}10^8 ~ 4.4{\times}10^8 $ cells/ml 범위로 큰 변화가 없었으나, Bacillus sp. 균수는 $0.3{\times}10^8 ~ 2.5{\times}10^8 $ cells/ml 범위로 지점별, 조사시기별로 큰 차이가 있었다. 포자수는 $0.3{\times}10^7 ~ 8.4{\times}10^7 $ cells/ml 범위로 3월에는 세 번째 포기조, 5월에는 두 번째 포기조에서 각각 8.5, $5.5{\times}10^7$cells/ml으로 높은 값을 보였다. 총세균수는 DAPH를 측정한 값과 포자수를 합하여 사용하였고, Bacillus속 세균수는 FISH로 계수된 수와 포자수를 합하여 사용하였다. 충세균수에 대한 Bacillus sp.균의 비율은 약 8~60% 범위로 첫 번째 및 세 번째 포기조에서 각각 50%, 35% 이상의 높은 비율을 보였다. B3 공법에서는 Bacillus가 우점하고 있음이 FISH 방법으로 확인되었으며, 반송 슬러지와 하수가 유입되는 첫 번째포기 조에서 그 비율이 높았고, 다음 포기조로 가면서 그 비율이 줄어들고 있었다. Bacillus의 포자수는 뒤의 포기조로 가면서 그 수와 비율이 높아지고 있었다.

• Membrane and Water Treatment
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• 제14권1호
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• pp.35-45
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• 2023

Biofilms significantly affect the performance of wastewater treatment processes in which biodegradability of numerous microorganisms are actively involved, and various technologies have been applied to secure microbial biofilms. Understanding changes in biofilm characteristics by regulating expression of signaling molecules is important to control and regulate biofilms in membrane bioreactor, i.e., biofouling. This study investigated effects of addition of acyl-homoserine lactones (AHL) as a controllable factor for the microbial signaling system on biofilm formation of Pseudomonas aeruginosa PAO1 and multiple strains in membrane bioreactor. The addition of three AHL, i.e., C4-, C6-, and C8-HSL, at a concentration of 200 ㎍/L, enhanced the formation of the PAO1 biofilm and the degree of increases in the biofilm formation of PAO1 were 70.2%, 76.6%, and 72.9%, respectively. The improvement of biofilm formation of individual strains by C4-HSL was an average of 68%, and the microbial consortia increased by approximately 52.1% in the presence of 200 ㎍/L C4-HSL. CLSM images showed that more bacterial cells were present on the membrane surface after the AHL application. In the COMSTAT results, biomass and thickness were increased up to 2.2 times (PAO1) and 1.6 times (multi-strains) by C4-HSL. This study clearly showed that biofilm formation was increased by the application of AHL to individual strain groups, including PAO1 and microbial consortia, and significant increases were observed when 50 or 100 ㎍/L AHL was administered. This suggests that AHL application can improve the biofilm formation of microorganisms, which could yield an enhancement in efficiency of biofilm control, such as in various biofilm reactors including membrane bioreactor and bioflocculent systems in water/wastewater treatment processes.

• 한국물환경학회지
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• 제26권4호
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• pp.574-579
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• 2010

In this study the enzyme inhibition method using dehydrogenase which has been popularly used to estimate ecotoxicity was optimized. When three bacterial strains, Escherichia coli HB101, Enterobacter asburiae KCAD-4, and Aeromonas media KCAD-13, were compared, KCAD-4 was considered as the adequate strain to estimate toxicity because of its sensitivity and reproducibility. The optimal bacterial density was estimated as $5.4{\times}10^9CFU/mL$, at which the maximum sensitivity was observed. The phosphate buffer was suitable for the reaction solution. When the reaction times required for inhibition of enzyme activity by contact of toxicants and for reaction of damaged bacteria and substrate were tested, the optimal value was estimated as 20 min and 2 hrs, respectively. It is expected that the optimized conditions can be used to develop the standardized kits to estimate ecotoxicity of heavy metals in effluent from the industrial wastewater treatment facilities.

• 한국환경농학회지
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• 제13권3호
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• pp.386-395
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• 1994

산업폐수 및 광산폐수 등으로부터 분리한 중금속 처리능력이 있는 미생물 균주들을 실제폐수처리에 적용시키기 위한 기초실험으로서 생물학적 활성슬러지공법의 소형폐수처리조를 이용한 각 중금속의 단독처리능력 및 여러가지 중금속의 동시 복합처리 능력을 조사한 결과를 요약하면 다음과 같다. 소형폐수처리조의 연속적인 처리과정에서의 각 중금속 처리균주들과 각 중금속들을 각각 단독으로 처리하여 HRT를 24시간으로 조절하였을 경우, 처리 12일 후 각 중금속 처리율은 Pb 처리균과 Pb만 100mg/l 되게 단독처리 했을때 처리수중 Pb 처리율은 약 93%였으며, Cd처리균과 Cd만 100mg/l 되게 단독처리하였을 경우 처리 12일 후 Cd 처리율은 약 90%였다. 그리고 Zn 처리균과 Zn만 100mg/l 되게 처리하였을 경우 처리 12일 후의 처리수중의 Zn 처리율은 약 80%였으며, Cu 처리균과 Cu만 단독으로 처리했을 경우에는 처리 12일 후 약 39%의 Cu 처리율을 나타내었다. 생물학적 활성슬러지공법의 소형폐수처리조를 이용한 연속처리과정에서의 여러가지 중금속과 여러가지 중금속처리균주들을 동시에 복합적으로 처리했을 경우의 여러가지 중금속의 동시 처리율을 조사한 결과는 다음과 같다. 폐수중 중금속 Pb, Cd, Zn 및 Cu 농도를 각각 100mg/l 되게 중금속을 복합 처리하고 각 중금속 내성균주(Pb, Cd, Zn 및 Cu내성균주)를 각각 1500mg/l의 MLSS가 되도록 복합 접종하여 소형폐수처리조에서 연속적으로 처리할 경우 HRT를 24시간으로 조절하였을 때 처리 12일 후 Pb, Cd, Zn 및 Cu의 처리율은 각각 75%, 90%,, 74% 및 48%였다.

• KSBB Journal
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• 제13권2호
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• pp.119-124
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• 1998

Twelve bacterial strains capable of growing on phenol minimal medium were isolated from iron foundry activated sludge by enrichment culture, and amount them, one isolate which was the best in cell growth and phenol degradation was selected and identified as Acinetobacter junii POH. The optimal temperature, initial pH and phenol concentration in the above medium were 3$0^{\circ}C$, 7.5 and 1000 ppm, respectively. Cell growth of Acinetobacter junii POH dramatically increased 20 hrs cultivation-time and reached a almost stationary phsae 40 hrs cultivation-time then phenol was degraded about 98%. Cell growth was inhibited y phenol at concentrations over 1500 ppm. The isolate was resistant to several antibiotics as well as various heavy metal ions. The growth-limiting log P value of Acinetobacter junii POH on organic solvents was 2.9 in the LB medium. Therefore, it is suggested that Acinetobacter junii POH could be effectively used for the biological treatment of wastewater containing the presence of heavy metal ions and organic solvents.

• 한국환경보건학회지
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• 제23권4호
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• pp.33-38
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• 1997

Four bacterial strains able to degrade dichlorobenzene as the sole source of carbon and energy were isolated from soil by selective enrichment culture, and among them, one isolation was the best in the cell growth and identified as Pseudomonas sp. DCB3 by its morphology and physiological properties. Cell growth dramatically increased in a minimal medium containing 500ppm of dichlorobenzene was not detected any more at 72 hours after cultivation. The optimal temperature and initial pH for the growth of the isolated strain were 30$\circ$C and 7.0, respectively. Cell growth was increased by supplementing $(NH_2)_2CO$ and 50 ppm yeast extract as additional nutrients. Therefore, it was suggested that Pseudomonas sp. DCB3 could be effectively used for the biological treatment of wastewater containing dichlorobenzene.

• Journal of Microbiology
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• 제35권3호
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• pp.193-199
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• 1997

From several industrial wastewaters, 14 bacterial strains which degrade benzene, toluene, o-xylene, m-xylene, or p-xylene (BTX) were obtained. These strains were characterized as to their species composition and the substrate range, kinetic parameters and the substrate interactions were investigated. Although BTX components have a similar chemical structure, isolated strains showed different substrate ranges and kinetic parameters. None of the strains could degrade all of BTX components and most of them showed an inhibition (Haldane) kinetics on BTX, BTX mixtures were removed under inhibitory substrate interactions with variation in the intensity of inhibition. For a complete degradation of BTX, a defined mixed culture containing three different types of patyways was constructed and all of the BTX components were simultaneously degraded with the totla removal rate of 225.69 mg/g biomass/h Judging from the results, the obtained mixed culture seems to be useful for the treatment of BTX-contaminated wastewater or groundwater as well as for the removal of BTX from the contaminated air stream.

• 미생물학회지
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• 제38권1호
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• pp.1-6
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• 2002

전분가공폐수처리장 활성슬러지와 논, 밭 토양에서 전분성분을 분해하는 $\alpha$-amylase를 생성하는 균주들을 분리 선별하였다. 이중 효소활성이 우수한 AIV 19를 형태학적 분석 및 API system 과 지방산분석(MIDI) 방법을 이용한 결과 Bacillus 속으로동정되었다. $\alpha$-amylase 생성능을 향상시키기 위해 nitrosoguanidine (NTG)처리를 한 균주 중 선별된 AIV 1940균주의 효소활성능이 원 균주에 비해 1.8배 향상되었다. 분리균주는 그람양성가균으로 길이가 2.3-5 $\mu$ m폭이 0.8-1$\mu$m이었고, Bioscreen C 시스템을 이용한 균주성장능 평가에서는 전분이 3 g/ι농도에서 성장능이 증가되었다. 전분합성폐수를 이용한 유기물제거실험에서는 초기 CODcr가 4,455 mg/ι인 고농도 합성폐수를 1일 3일 반응 후 각각 40.2% 72.3%의 유기물 제거율을 나타내었다.

• Advances in environmental research
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• 제2권3호
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• pp.229-243
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• 2013

Coagulation-flocculation (CF) was tested coupled with an aerobic biofilter to reduce total petroleum hydrocarbon (TPHs) concentration and toxicity from petrochemical wastewater. The efficiency of the process was followed using turbidity and chemical oxygen demand (COD). The biofilter was packed with a basaltic waste (tezontle) and inoculated with a bacterial consortium. Toxicity test were carried out using Lactuca sativa var. capitata seeds. Best results for turbidity removal were obtained using alum. Considerable turbidity removal was obtained when using Opuntia spp. COD removal with alum was 25%, for Opuntia powder it was 36%. The application of the biofilter allowed the removal of 70% of the remaining TPHs after 30 days with a biodegradation rate (BDR) value 47 $mgL^{-1}d^{-1}$. COD removal was slightly higher with BDR value 63 $mgL^{-1}d^{-1}$. TPH kinetics allowed a degradation rate constant equal to $4.05{\times}10^{-2}d^{-1}$. COD removal showed similar trend with $k=4.23{\times}10^{-2}d^{-1}$. Toxicity reduction was also successfully achieved by the combined treatment process.