• Fisheries and Aquatic Sciences
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• v.8 no.1
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• pp.1-5
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• 2005

Cell growth of the marine microalga Tetraselmis suecica was regulated by the addition of seaweed extracts in its culture medium. Of 26 species of seaweed tested, water-soluble extracts from Monostroma nitidum and Pachymeniopsis elliptica and methanol-soluble extract from Sargassum confilsum enhanced the growth of T suecica cells. The water extract of M. nitidum was the most effective, producing up to a 2-fold increase in cell density with the addition of 1 mg/mL of extract to the culture medium. Cell size, gross biochemical composition, fatty acids, and digestion efficiency all differed marginally between cultures of T suecica grown with and without the M. nitidum extract.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2001.11a
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• pp.21-22
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• 2001

Phospholipase A$_2$(PLA$_2$) comprise a family of enzymes that hydrolyze the acyl bond at the sn-2 position of phospholipids to generate free fatty acids including arachidonic acid and lysophospholipids. Distinct forms of PLA$_2$are involved in digestion, inflammation, and intercelluar-and intracellular signaling pathways. The released arachidonic acid, which is enriched at the sn-2 position, serves as the precursor for eicosanoids such as prostaglandins and leukotrienes. During oxygenation of arachidonic acid to hydroxy endoperoxide, reactive oxygen radicals are generated. On the other hand, lysophospholipids increase membrane fluidity and can be cytotoxic with its detergent-like action. Thus, the biochemical features of the products of PLA$_2$activity suggest that PLA$_2$may be implicated in many destructive cellular processes.

• Archives of Pharmacal Research
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• v.21 no.1
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• pp.35-40
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• 1998

Human cytochrome P450 4F2 shows high regioselectivity in hydroxylation of stearic acid and leukotriene $ B_4.$ As a first step of its regulation study, human cytochrome P450 4F2 genomic DNA was isolated from liver of a person who was administered clofibrate for 10 years. From Southern hybridization, restriction enzyme digestion and sequencing experiments, isolated genomic DNA fragment was found to contain around 32 Kb DNA and more than 20 Kb of $5^I$ end regulatory region. Sequences of the structural gene region revealed exon 1 and exon 2. Further regulation studies would elucidate the feedback mechanisms of the oxidative degradation of fatty acids, inflammatory response and the clearance of leukotriene B4 in the liver. Furthermore, regulation study of this gene could explain the species difference in responses to peroxisome proliferator and help in the safety evaluation of peroxisome proliferating chemicals to human being.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1075-1080
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• 2009

The partial lipid degradation with the saturation of double-bond at the acidogenesis stage is known to help subsequent methanogenesis during anaerobic digestion. Acidogenic reactions in an anaerobic sequencing batch reactor (ASBR) and a continuously stirred tank reactor (CSTR) were carried out to compare their performances. A mixture of two unsaturated (oleate and linoleate) and two saturated (palmitate and stearate) long-chain fatty acids (LCFAs) was used as a model substrate. Biomass retention in the ASBR contributed to the enhanced performance at hydraulic retention time (HRT) below 15 hr. Biomass retention in the ASBR contributed to the enhanced performance compared to CSTR even at shorter HRT. ASBR would be a proper reactor configuration for the acidogenesis of lipid-containing wastewater.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.10
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• pp.1456-1463
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• 2017

Objective: To investigate the effect of host genetics on gut microbial diversity, we performed a structural survey of the fecal microbiota of four purebred boar pig lines: Duroc, Landrace, Hampshire, and Yorkshire. Methods: The V3-V4 regions of the 16S rRNA genes were amplified and sequenced. Results: A total of 783 operational taxonomic units were shared by all breeds, whereas others were breed-specific. Firmicutes and Bacteroidetes dominated the majority of the fecal microbiota; Clostridia, Bacilli, and Bacteroidia were the major classes. Nine predominant genera were observed in all breeds and eight of them can produce short-chain fatty acids. Some bacteria can secrete cellulase to aid fiber digestion by the host. Butyric, isobutyric, valeric, and isovaleric acid levels were highest in Landrace pigs, whereas acetic and propionic acid were highest in the Hampshire breed. Heatmap was used to revealed breed-specific bacteria. Principal coordinate analysis of fecal bacteria revealed that the Landrace and Yorkshire breeds had high similarity and were clearly separated from the Duroc and Hampshire breeds. Conclusion: Overall, this study is the first time to compare the fecal microbiomes of four breeds of boar pig by high-throughput sequencing and to use Spearman's rank correlation to analyze competition and cooperation among the core bacteria.

• Journal of Korean Society on Water Environment
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• v.32 no.3
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• pp.297-302
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• 2016

Microbial electrochemical technology (MET) has recently been studied to improve the efficiency of a traditional anaerobic digestion (AD). The purpose of this study was to investigate the impact of MET in the system when MET was combined with traditional AD (i.e., AD-MET). Electrodes used in the MET were Cu coated graphite electrodes. They were supplied with a voltage of 0.3 V. AD started to generate methane in 80 days. But AD-MET started to generate methane from the initial operation after the system started. It was observed that AD-MET reached steady state faster and produced higher methane yield than AD. During the steady state, the average daily methane productions in AD and AD-MET were 2.3L/d and 4.9L/d, respectively. Methane yields were 0.07-CH₄/g‧CODre in AD and 0.25L-CH₄/g‧CODre in AD-MET. In AD-MET, the production rates of total volatile fatty acids (TVFAs) and soluble chemical oxygen demand (SCOD) were 0.12 mg TVFAs/mg VS‧d and 0.35 mg SCOD/mg VS‧d, respectively. They were significantly (p < 0.05) higher than those in AD. However, the concentrations of residual TVFAs in both systems were not significantly (p > 0.05) different from each other, confirming that methane conversion in AD-MET was greater than that in AD.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1110-1117
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• 2001

Responses of the rumen fungus, Neocallimastix frontalis RE1, to long chain fatty acid (LCFA) were evaluated by measuring gas production, filter paper (FP) cellulose digestion and polysaccharidase enzyme activities. LCFA (stearic acid, $C_{18:0}$; oleic acid, $C_{18:1}$; linoleic acid, $C_{18:2}$ and linolenic acid, $C_{18:3}$) were emulsitied by ultrasonication under anaerobic condition, and added to the medium. When N frontalis RE1 was grown in culture with stearic, oleic and linoleic acid, the cumulative gas production, gas pool size, FP cellulose digestion and enzymes activities significantly (p<0.05) increased at some incubation times(especially, exponential phases of fungal growth, 48~120 h of incubation) relative to that for control cultures. However, the addition of linolenic acid strongly inhibited all of the investigated parameters up to 120 h incubation, but not after 168 and 216 h of incubation. These results indicated that stearic, oleic and linoleic acids tended to have great stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (p<0.05) inhibitory effects on the cellulolysis by the rumen fungus. These results are the first report of the effect of LCFAs on the ruminal fungi. Further research is needed to identify the mode of action of LCFAs on fungal strains and to verify whether or not ruminal fungi have ability to hydrate unsaturated LCFAs to saturated FAs. There was high correlation between cumulative in vitro gas production and fungal growth (94.78%), FP cellulose degradation (96.34%), CMCase activity(90.86%) or xylanase activity (87.67%). Thus measuring of cumulative gas production could be a useful tool for evaluating fungal growth and/or enzyme production by ruminal fungi.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.397-397
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• 2022

오늘날 급격한 인구증가 및 도시화로 인해 음식물류 폐기물 발생량이 크게 증가하였으며, 음식물류 폐기물에서 발생되는 음폐수의 적절한 처리방안에 대한 관심이 증가하였다. 혐기성 소화(Anaerobic digestion; AD)는 음폐수의 바람직한 처리방법으로 알려졌지만, 긴 처리기간 및 공정 불안정 등의 문제로 개선이 필요하며, 그 중 기존 AD에 보조 반응조를 추가한 보조 미생물전기화학적 혐기성소화(Auxiliary bioelectrochemical anaerobic digestion; ABEAD)가 적절한 개선방안으로 제시되었다. 하지만 아직 20 L 이상 용량에서의 연구는 이뤄지지 않았으며, 따라서 본 연구에서는 100 L의 용량에서 ABEAD의 성능향상을 평가하고 규모증가에 따른 성능변화를 비교하였다. 반응조는 AD와 ABEAD로 구성되었다. 유효용량 100 L, 유기물부하율 4 kg/m³/d, HRT 20 days 및 중온소화(35℃) 조건으로 운전하였으며, AD는 기계적 교반, ABEAD는 기계적 교반 및 펌프를 통한 bulk 용액 순환이 이뤄졌다. ABEAD의 전극재질은 SUS304를 사용하였고, 0.4V의 전압을 공급하였다. 성능비교는 pH, 휘발성지방산(Volatile fatty acids; VFAs), 유기물제거율 및 메탄 생성량을 비교해 수행하였다. 실험결과 AD는 pH 및 VFAs가 각각 평균 7.37 및 3,880 mg/L, ABEAD는 각각 평균 7.5 및 2,870 mg/L로 VFAs의 빠른 처리를 통해 공정안전성 향상되었고, 유기물제거율 및 메탄생성량의 경우 AD는 각각 평균 65.8 % 및 85.1 L/d, ABEAD는 각각 평균 76.1 % 및 108.1 L/d로 유기물의 빠른 처리 및 메탄전환이 이루어져 비교적 큰 규모에서도 ABEAD의 성능향상이 나타남을 확인하였다. 또한 이전 소규모 연구들과 비교를 통해 규모에 따른 성능향상폭을 비교했을 때에도 큰 차이가 나지 않는 것으로 판단되며, 따라서 ABEAD는 BEAD 기술의 상용화 및 적용에 적합한 것으로 사료된다.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.131-138
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• 2024

The effect of magnetite particles on the anaerobic digestion (AD) of furfural wastewater was investigated using sequential anaerobic batch tests. The batch tests with four 500 mL anaerobic bioreactors were performed under two conditions: FC treatment for AD of furfural without magnetite particles, and FM treatment for AD of furfural with magnetite particles. The FC bioreactors showed a decreasing methane production rate (MPR) across the sequential batches, with a final batch MPR of 11.3 ± 0.4 mL CH₄/L/d, indicating the need for a methanogenesis enhancer to achieve high-rate AD of furfural. Conversely, FM bioreactors exhibited significantly higher MPR, exceeding FC values by 4-196%, with a final batch MPR of 33.5 ± 0.1 mL CH₄/L/d, which was about three times higher than FC. Additionally, FM bioreactors had faster degradation rates of furfural, valeric acid, and acetic acid compared to FC, with values exceeding those in PC by 3.0, 1.14, and 2.8 times, respectively. These results demonstrate that magnetite particles can enhance the AD of furfural not only by accelerating methanogenesis but also by accelerating the anaerobic degradation of furfural and its intermediates, such as volatile fatty acids. This study provides valuable insights for developing high-rate AD systems for furfural wastewater treatment.

• Korean Journal of Environmental Agriculture
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• v.23 no.1
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• pp.1-6
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• 2004

The seeding sources and concentration of ammonia on anaerobic digestion were investigated by batch culture bioreactors. The sources of seeding on anaerobic digestion were from swine wastewater collection pit of a hog raising farm and from anaerobic digestion sludge of a municipal sewage treatment plant. The inhibition of ammonia on anaerobic microorganisms was initiated at ammonia concentration of $1,500\;mgNH_4-N/L$ and it's effect was increased by increased by increasing ammonia concentration up to $3,500\;mgNH_4-N/L$ regardless the sources of seeding as evidenced by decreases in COD removal efficiencies and biogas yields. The inhibition occurred to not only methanogens but also acidogens since the concentration of volatile fatty acids was maintained at 50 mg/L The COD removal efficiency and biogas yield were Maintained constantly while increasing ammonia concentration up to $3,500\;mgNH_4-N/L$ when swine wastewater collection pit was used as a seeding; however, those were decreased while increasing ammonia concentration when anaerobic digestion sludge was used as a seeding. The results indicate that the seeding acclimated to high concentrations of ammonia for long time was easy in adaptation to high ammonia concentration and less subjective to ammonia inhibitory effects.