• Ecology and Resilient Infrastructure
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• 제9권3호
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• pp.183-193
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• 2022

초음파 (ultrasonic) 조사시간 (irradiation time)에 따른 Microcystis aeruginosa (M. aeruginosa)의 성장억제 (growth inhibition) 효과를 대용량 (10 L) 조류 시료를 활용해 다양한 초음파 조사시간 동안 (0.5, 1, 1.5, 2, 2.5, 3 hr) 실험실 규모 (lab-scale) 실험을 진행하였다. Chl-a와 M. aeruginosa 개체수 (cell number) 분석 결과, 초음파 조사 종료 이후 모든 실험군에서 Chl-a와 개체수가 감소되어 조류 성장억제가 관찰되었으며, 초음파 조사시간이 2시간 미만인 실험군 (T_B, T_C, T_D)은 저감 이후 조류의 급격한 재성장 (regrowth)이 관측되었으나, 조사시간이 2시간 이상인 실험군 (T_E, T_F, T_G)은 2시간 미만 조사한 실험군 대비 조류성장억제가 1 - 2일 더 지속되는 것을 확인하였다. 또한, 조류의 개체수가 초기 개체수까지 회복 시간 (recovery time)을 검토한 결과 조사시간 2시간을 기준으로 실험군 T_B (0.5 hr)는 7일, T_C (1 hr)와 T_D (1.5 hr)는 약 20일, T_E, T_F, T_G (≥ 2 hr)는 약 30일이 소요되어 초음파 조사 종료 후 초기 개체수까지의 회복 시간의 차이를 확인하였다. 비성장속도 (𝜇)와 일차분해속도(𝜅)를 도출한 결과, 실험군은 성장억제 기간 동안 초음파 조사시간과 비례하여 높은 일차분해율이 도출되었으며, 조사시간이 2시간 이상인 실험군의 재성장 시 비성장속도 (𝜇)는 2시간 미만인 실험군 대비 비성장속도 (𝜇)가 상대적으로 낮은 것으로 확인되었다. 따라서 정체수역 내 장기적인 (30일) 조류 성장억제를 위해서는 최소한 2시간 이상의 초음파 조사가 필요한 것으로 판단되나, 조류 성장억제를 위한 적정 초음파 조사시간은 정체수역의 규모, 수심, 흐름속도, 조류 농도 등의 다양한 현장조건에 따라 결정돼야 하며, 실제 적용 가능성을 높이기 위한 추가 연구가 필요한 것으로 판단된다. 초음파의 영향으로 인한 M. aeruginosa의 세포 표면 및 내부형질 변화를 관찰한 결과, 조류 세포 표면 및 세포막의 손상이 명확히 관측되었으며, 대조군 대비 실험군의 M. aeruginosa의 기낭 파괴 및 교란이 확인되었다.

• 청정기술
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• 제21권4호
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• pp.257-264
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• 2015

본 연구에서는 일반적인 물리·화학적 조류 증식 억제 방법의 문제점이 보완되어진 자연친화적인 생물학적 억제방법을 이용하고자 하였다. 섬유상 담체들의 생물막 형성 두께와 물리적 특성을 비교한 결과, 폴리에스터 담체가 가장 적절하였다. 이를 이용하여 부영양화 호소에서의 영양염류 제거와 조류증식 억제 효율을 분석하였다. 질소, 인 제거율은 14.59%, 6.36%, 그리고 조류증식 억제효율 비교를 위한 식물플랑크톤 성장 억제률은 77%로 영양염류와 식물플랑크톤 수치가 증가한 대조군에 비해서 높은 효율을 나타냈다. 따라서 본 연구에서는 폴리에스터 섬유상 담체를 적용하여 호소에서 자연친화적인 생물학적 처리가 가능할 것으로 판단된다.

• ALGAE
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• 제19권1호
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• pp.7-14
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• 2004

Blue-Min was initially developed as an adsorbent for harmful gas removal and recently improved to apply to livestock, agriculture and aquaculture as an assistant feed. In the Blue-Min treatment, growth of harmful algae (Cochlodinium polykrikoides and the others causing the red-tide in the ocean) were inhibited below 10% in comparison with control and coagulation removal of harmful alge with Blue-Min treatment was more efficient than that of yellow loess treatment. It would be expected that the Ble-Min can be useful for the extirpator against the red-tide organisms and restrain the toxic algal growth around the fish aquaculture using the assistant feed. Recently, its utility has become to be diverse as it was revealed that aquaculture productivity increase by its application and, in addition, that it improve the water quality or sediment conditions in the aquaculture of Chinese White Shrimp. When Blue-Min was treated with the proper dose, the growth inhibition of Microcystis aeruginosa and lsochrysis galbana, which are typical red-tide organisms in freshwaters and food organisms in aquaculture, respectively, were less than that of marine red-tide organisms, while their growth slightly increased with low concentration treatiment. In addition, polyunsaturated fatty acids (PUFA) content of I. galbana slightly increase with the Blue-Min treatment. Through our research, the Blue-Min has diverse and comples function against various biological organisms and is proved as a biological activator or depressor.

• 한국미생물·생명공학회지
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• 제17권2호
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• pp.170-172
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• 1989

It is preyed that marine algae, Chlorella pyrenoidosa can synthesize about 3.52% of eicosapentaenoic (EPA) of dry cell weight at the light intensity of 10 W/$\m^2$ which is optimal light intensity of producing EPA at $25^{\circ}C$. An equation to predict the amounts of EPA in the culture broth is derived as an exponential form with 0.91 of the correlation factor. The behavior of cell growth follows a photo-inhibition model by showing 12 W/$\m^2$ of saturation light intensity.

• 한국물환경학회지
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• 제33권5호
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• pp.538-545
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• 2017

The purpose of this study is to investigate growth response and toxigenicity under various temperature and nutritional conditions, in order to understand the physioecological characteristics of Aphanizomenon flos-aquae, which is a bloom-forming cyanobacterium in the Nakdong River. The strain was inoculated into media under combinations of four temperatures (4, 12, 21, $30^{\circ}C$) and three nutrients (modified CB medium, P-depleted CB medium, N-depleted CB medium) for 28 days. The algae-inhibition tests were performed to assess the potential allelopathic effects of the strains' filtrates on the growth of four algae strains (Microcystis aeruginosa, Aulacoseria ambigua f. spiralis, Aphanizomenon flos-aquae, Scenedesmus obliquus). Toxin production of a strain was measured by Enzyme-Linked ImmunoSolbent Assay (ELISA). The optimal growth temperature (Topt) of strains was $19.9^{\circ}C$ ($18.3-21.2^{\circ}C$), and the temperature range for growth was from $-0.3^{\circ}C$ to $34.3^{\circ}C$. Specific growth rate (${\mu}$) in modified CB medium varied from 0.10 to $0.16day^{-1}$, and the maximum growth rate (${\mu}_{max}$) was $0.17day^{-1}$. Although growth curves under N-existed and N-depleted conditions were almost the same, growth under N-depleted condition was relatively slowed (${\mu}=0.09$ to $0.14day^{-1}$), with a decreased maximum cell density. However, growth under the P-depleted condition was restricted for all temperatures, Two stains of Aphanizomenon flos-aquae were confirmed as not producing toxins, because saxitoxin and cylindrospermopsin were not detected by ELISA. The exudates or filtrates from the Aphanizomenon flos-aquae (DGUC003) resulted in significant inhibition of algal growth on the Aulacoseira ambigua f. spiralis (DGUD001) and Aphanizomenon flos-aquae (DGUC001) (p < 0.01).

• Ecology and Resilient Infrastructure
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• 제5권3호
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• pp.174-179
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• 2018

$TiO_2$-embedded expanded polystyrene (TiEPS) balls with powdered $TiO_2$ particles embedded on the surface of EPS were developed, and the growth inhibition of Chlorella ellipsoidea, a green algae, was evaluated. The experiment was conducted using four reactors with various conditions of (A) natural sunlight, (B) natural sunlight + TiEPS balls, (C) dark, and (D) dark + TiEPS balls on the roof of the building during five days. Based on the analysis of cell number, cell morphology, concentrations of chlorophyll-a and phaeopigments, both surface reactions in heterogeneous photocatalysis and light shielding could inhibit the growth of C. ellipsoidea. The highly reactive hydroxyl radicals ($OH{\cdot}$) from TiEPS balls degraded the lipid cell membrane through the peroxidation reaction with the light shielding, eventually resulting in cell inactivation. Although dominant inhibitory effects on the growth of C. ellipsoidea were ambiguous, TiEPS balls were feasible to prevent and inhibit the excessive growth of algae in eutrophic water body.

• 한국농공학회논문집
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• 제52권6호
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• pp.19-26
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• 2010

Batch experiments were conducted to investigate growth and nutrient removal performance of microalgae Chlorella vulgaris by using piggery wastewater in different concentration of pollutants and the common growth models (logistic, Gompertz and Richards) were applied to compare microalgal growth parameters. Removal of nitrogen (N) and phosphorus (P) by Chlorella vulgaris showed correlation with biomass increase, implying nutrient uptake coupled with microalgae growth. The higher the levels of suspended solids (SS), COD and ammonia nitrogen were in the wastewater, the worse growth of Chlorella vulgaris was observed, showing the occurrence of growth inhibition in higher concentration of those pollutants. The growth parameters were estimated by non-linear regression of three growth curves for comparative analyses. Determination of growth parameters were more accurate with population as a variable than the logarithm of population in terms of R square. Richards model represented better fit comparing with logistic and Gompertz model. However, Richards model showed some complexity and sensitivity in calculation. In the cases tested, both logistic and Gompertz equation were proper to describe the growth of microalgae on piggery wastewater as well as easy to application.

• Journal of Microbiology and Biotechnology
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• 제24권4호
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• pp.465-474
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• 2014

This study was performed to investigate the inhibitory effects of brown algae extracts on histamine production in mackerel muscle. First, antimicrobial activities of brown algae extracts against Morganella morganii were investigated using a disk diffusion method. An ethanol extract of Ecklonia cava (ECEE) exhibited strong antimicrobial activity. The minimum inhibitory concentration (MIC) of ECEE was 2 mg/ml. Furthermore, the brown algae extracts were examined for their ability to inhibit crude histidine decarboxylase (HDC) of M. morganii. The ethanol extract of Eisenia bicyclis (EBEE) and ECEE exhibited significant inhibitory activities (19.82% and 33.79%, respectively) at a concentration of 1 mg/ml. To obtain the phlorotannin dieckol, ECEE and EBEE were subjected to liquid-liquid extraction, silica gel column chromatography, and HPLC. Dieckol exhibited substantial inhibitory activity with an $IC_{50}$ value of 0.61 mg/ml, and exhibited competitive inhibition. These extracts were also tested on mackerel muscle. The viable cell counts and histamine production in mackerel muscle inoculated with M. morganii treated with ${\geq}2.5 $ MIC of ECEE (weight basis) were highly inhibited compared with the untreated sample. Furthermore, treatment of crude HD-Cinoculated mackerel muscle with 0.5% ECEE and 0.5% EBEE (weight basis), which exhibited excellent inhibitory activities against crude HDC, reduced the overall histamine production by 46.29% and 56.89%, respectively, compared with the untreated sample. Thus, these inhibitory effects of ECEE and EBEE should be helpful in enhancing the safety of mackerel by suppressing histamine production in this fish species.

• 농약과학회지
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• 제12권1호
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• pp.82-87
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• 2008

우리나라에서 사용되고 있는 벼재배용 제초제인 butachlor의 담수조류에 대한 생장영향을 알아보고자 녹조류 Selenastrum capriconutum, Scenedesmus subspicatus, Chlorella vulgaris 3종과 규조류 Nitzschia palea 1종에 대해 72시간 생장저해시험(growth inhibition test)을 수행하였다. 시험결과 butachlor에 대한 S. capricornutum, S. subspicatus, C. vulgaris, 그리고 N. palea의 생장율 기준 반수영향농도($EC_{50}$)는 각각 0.0022, 0.019, 8.67 그리고 $4.94\;mg\;L^{-1}$이었고, 무영향농도(NOEC)는 0.0008, 0.0016, 5.34 그리고 $2.92\;mg\;L^{-1}$로 나타나 S. capricornutum가 가장 높은 감수성을 보였다. 양성대조물질인 $K_2Cr_2O_7$에 대한 S. capricornutum, S. subspicatus, C. vulgaris 그리고 N. palea의 생장율 기준 $EC_{50}$은 각각 0.91 0.78, 0.85 그리고 0.57 mg $EC_{50}$이었고, NOEC는 각각 0.2, 0.2, 0.2 그리고 0.18 mg $EC_{50}$였다. butachlor를 논에 살포하였을 때 논물에 전량 용해된 후 배수로를 통해 농수로에 배출될 때를 가정한 환경추정농도(Predicted Environmental Concentration; PEC)에 따른 생장저해율을 계산한 결과, S. capricornutum와 S. subspicatus는 각각 100%와 75%의 생장율 저해를 보였으나 C. vulgaris와 N. palea는 영향이 없었다.

• 한국물환경학회지
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• 제33권1호
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• pp.8-14
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• 2017

Microcystis aeruginosa (M. aeruginosa) is a cyanobacterium species that can form harmful algal blooms in freshwater bodies worldwide. The use of pine needle extract (PNE) to control nuisance algae by allelopathic inhibition will be environmentally friendly and promising. PNE removed successfully upto 98% of M. aeruginosa at the following optimal conditions: pH 7, $25^{\circ}C$ of temperature, 100 rpm of mixing rate, 5 min of mixing time. These results was indicated that the amount of 1 g/L PNE was removed 1g dryweight/L of M. aeruginosa. The kinetic data showed substrate inhibition kinetics and maximum growth rate was obtained when the M. aeruginosa was grown in medium containing 0.5 g/L of initial concentration of PNE. Different substrate inhibition models were fitted to the kinetic data and found the Luong model was best. The model predicted kinetic parameters were in agreement with the experimental findings. The natural extract, PNE, can be a promising inhibition due to its high efficiency and low dose requirements.