• Journal of Animal Science and Technology
• /
• 제62권4호
• /
• pp.504-520
• /
• 2020

Proliferation of shrubs at the expense of native forage in pastures has been associated with large changes in dry-matter intake and dietary components for grazing ruminants. These changes can also affect the animals' physiology and metabolism. However, little information is available concerning the effect of pastoral-shrub grazing on the rumen bacterial community. To explore rumen bacteria composition in grazing yaks and the response of rumen bacteria to increasing shrub coverage in alpine meadows, 48 yak steers were randomly assigned to four pastures with shrub coverage of 0%, 5.4%, 11.3%, and 20.1% (referred as control, low, middle, and high, respectively), and ruminal fluid was collected from four yaks from each pasture group after 85 days. Rumen fermentation products were measured and microbiota composition determined using Ion S5™ XL sequencing of the 16S rRNA gene. Principal coordinates analysis (PCoA) and similarity analysis indicated that the degree of shrub coverage correlated with altered rumen bacterial composition of yaks grazing in alpine shrub meadows. At the phyla level, the relative abundance of Firmicutes in rumen increased with increasing shrub coverage, whereas the proportions of Bacteroidetes, Cyanobacteria and Verrucomicrobia decreased. Yaks grazing in the high shrub-coverage pasture had decreased species of the genus Prevotellaceae UCG-001, Lachnospiraceae XPB1014 group, Lachnospiraceae AC2044 group, Lachnospiraceae FCS020 group and Fretibacterium, but increased species of Christensenellaceae R-7 group, Ruminococcaceae NK4A214 group, Ruminococcus 1, Ruminococcaceae UCG-002, Ruminococcaceae UCG-005 and Lachnospiraceae UCG-008. These variations can enhance the animals' utilization efficiencies of cellulose and hemicellulose from native forage. Meanwhile, yaks grazed in the high shrub-coverage pasture had increased concentrations of ammonia nitrogen (NH₃-N) and branched-chain volatile fatty acids (isobutyrate and isovalerate) in rumen compared with yaks grazing in the pasture without shrubs. These results indicate that yaks grazing in a high shrub-coverage pasture may have improved dietary energy utilization and enhanced resistance to cold stress during the winter. Our findings provide evidence for the influence of shrub coverage on the rumen bacterial community of yaks grazing in alpine meadows as well as insights into the sustainable production of grazing yaks on lands with increasing shrub coverage on the Qinghai-Tibet Plateau.

• Asian-Australasian Journal of Animal Sciences
• /
• 제16권12호
• /
• pp.1763-1769
• /
• 2003

Two experiments were conducted to examine the production and quality of cassava hay and its utilization in diets for dairy cows. In experiment I, a $2{\times}2$ Factorial arrangement in a randomized complete block design with 4 replications was carried out to determine the effects of different initial (IC) and subsequent cutting (SC) on yield and composition of cassava plant. The results revealed that cassava could produce from 4 to 7 tonne of DM and 1.2 to 1.6 tonne of CP for the first six months after planting. CP content in cassava plant ranged from 20.8 to 28.5% and was affected by different SC regimes. Condensed tannin in cassava foliage ranged from 4.9 to 5.5%. Initial cutting at 2 months with subsequent cutting at 2 month intervals was the optimal to obtain high dry matter and protein yield. In the second experiment, five crossbred Holstein-Friesian cows in mid lactation with an initial live-weight of 505${\pm}6.1kg$ and average milk yield of 10.78${\pm}1.2kg/d$ were randomly assigned in a $5{\times}5$ Latin square design to study the effects of 2 levels of CH (1 and 2 kg/hd/d) and concentrate (1 to 2 kg of milk and 1 to 3 kg of milk) on milk yield and milk composition. The results showed that cassava hay increased rumen $NH_3-N$ and milk urea nitrogen (MUN) (p<0.05). Cassava hay tended to increase milk production and 4% FCM. Milk protein increased in cows fed cassava hay (p<0.05). Moreover, cassava hay could reduce concentrate levels in dairy rations thus resulting in increased economic returns. Cassava hay can be a good source of forage to reduce concentrate supplementation and improve milk quality.

• 한국토양비료학회지
• /
• 제16권4호
• /
• pp.311-317
• /
• 1983

논토양성분(土壤成分)의 용탈(溶脫)에 미치는 볏짚의 영향(影響)을 구명(究明)하기 위하여 논토양(土壤)에 볏짚을 시용(施用)하고 투수조건하(透水條件下)에서 수도(水稻)를 재배(栽培)하면서 침투수중(浸透水中) 용탈성분(溶脫成分)을 분석(分析) 검토(檢討)한 결과(結果)는 다음과 같다. 석회(石灰)와 고토(苦土)의 용탈(溶脫)은 초기(初期)에는 볏짚시용(施用)의 영향(影響)을 받았고 후기(後期)에는 수도근(水稻根)의 영향(影響)을 받았으며 철(鐵)과 망간의 초기용탈(初期溶脫)은 볏짚시용(施用)에 의(依)한 토양환원(土壤還元) 발달(發達)의 영향(影響)을 받았으나 후기(後期)에는 수도근(水稻根)의 영향(影響)을 크게 받아 증대(增大)되었다. 칼리, $NH_4-N$, 염소(鹽素) 등(等)의 용탈(溶脫)은 볏짚시용(施用)의 영향(影響)이 크지 않았으며 $CO_2$의 용탈(溶脫)은 볏짚의 영향(影響)을 받아 증대(增大)되고 동시(同時)에 수도근(水稻根)의 영향(影響)이 컸다. 침투수중(浸透水中) 용탈(溶脫)되는 양(陽)이온과 음(陰)이온의 양(量)은 대체로 같은 당량비(當量比)였으며 양(陽)이온은 석회(石灰)와 고토(苦土), 철(鐵), 음(陰)이온은 $HCO_3{^-}$과 $SO_4{^{-2}}$이 중요(重要)한 용탈성분(溶脫成分)이었다.

• 상하수도학회지
• /
• 제13권2호
• /
• pp.55-65
• /
• 1999

AF(anaerobic filter)/BAF(biological aerated filter) system and UASB(upflow anaerobic sludge blanket)/BAF system, of which system effluents were recirculated to the anaerobic reactors in each system, were operated in order to investigate the performance in simultaneous removal of organics and nitrogen in high-strength dairy wastewater. Advanced anaerobic treatment processes of AF and UASB were evaluated on applicability as pre-denitrification reactors, and BAF was also evaluated on the performance in oxidizing the remaining organics and ammonia nitrogen. At system HRTs of 4.0 to 4.5 days and recirculation ratios of one to three, the AF/BAF system could achieve more than 99% of organics removals and 64 to 78% of total nitrogen removals depending upon the recirculation ratio. Although the UASB/BAF system also showed more than 99% of organics removals, total nitrogen removals in the UASB/BAF system were 53 to 66% which are lower than those in the AF/BAF system at the corresponding recirculation ratios. Optimum recirculation ratios considering simultaneous removal of organics and nitrogen and cost-effectiveness, were in the range of two to three. The upflow AF packed with crossflow module media, as a primary treatment of the anaerobic reactor/BAF system, showed better performances in denitrification, SS removals, and gas production than the UASB. Higher loading rate of suspended solids from the UASB increased the backwashing times in the following BAF. Especially, at a recirculation ratio of three in the UASB/BAF system, the increase in head loss due to clogging in the BAF caused frequent backwashing, at least once d day. The BAF showed the high nitrification efficiency of average 99.2% and organics removals more than 90% at organics loading rate less than $1.4KgCOD/m^3/d$ and $COD/NH_3-N$ ratio less than 6.4. It was proved that the simplified anaerobic reactor/BAF system could maximize the organics removal and achieve high nitrogen removal efficiencies through recirculation of system effluents to the anaerobic reactor. The AF/BAF system can, especially, be a cost effective and competitive alternative for the simultaneous removal of organics ana nitrogen from wastewaters.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2011년도 학술발표회
• /
• pp.287-287
• /
• 2011

모니터링 자료의 부족으로 인하여 다양한 토지이용에서 발생하는 비점오염물질의 관리에 어려움을 겪고 있는 실정이다. 현재 환경부에서는 현행 토지계의 원단위를 세부적으로 분류하여 재산정하기 위하여 지목별로 장기 모니터링이 수행되고 있다. 특히, 산림 지역의 경우 도시 및 축산지역에 비하여 강우유출수의 농도는 낮더라도 유량적인 측면에 보았을 때 전체 수계에 대한 부하량 기여도는 매우 높다고 볼 수 있다. 따라서 본 연구는 장기모니터링의 일환으로 산림지역에 대한 비점오염물질 유출 특성을 파악하기 위하여 모니터링 및 분석을 실시하였으며, 이러한 결과는 향후 비점오염원 평가기반을 마련하고자 한다. 본 연구는 활엽수지역을 대상으로 2010년 4월부터 10월까지 총 16회에 걸쳐 모니터링이 수행되었으며, 시료의 성분 변화를 막기 위해 냉장기능이 있는 자동채수기를 이용하여 시료를 채취하였다. 수질분석항목은 BOD, COD, DOC, SS, T-N, $NO_3$-N, $NH_3$-N, T-P, $PO_4$-P로 총 9가지 항목을 분석하였다. 강우사상에 대한 모니터링 결과, 총강우량은 7.0~76.5mm, 강우지속시간은 1~30hr, 평균 강우강도는 0.88~18.50mm/hr의 범위를 보이고 있으며, EMC(Event Mean Concentration, 유량가중평균농도)결과 BOD는 0.4~2.4mg/L, T-N은 1.156~14.777mg/L, T-P는 0.009~0.562mg/L인 것으로 나타났으며, SS는 1.8~71.9mg/L 로 비교적 높은 값을 나타내는 것으로 분석되었다. 농도 변화 및 유출경향의 패턴을 볼 때, 유량이 증가함에 따라 농도도 점점 증가하여 첨두유량이 발생된 후 감소하는 경향을 나타내는 것으로 분석되었다. 또한 우리나라의 경우, 시험유역을 대개 산지 소유역에 설치하는 경우가 많아서 일반적으로 지연시간이 짧은 경우가 많기 때문에 이 지역 역시 강우가 내린 후 계류유출량의 증가에 영향을 주는 강우의 유출속도는 비교적 빠른 것으로 나타났다. 그리고 단기 수문곡선상에서 강우량이 많을 시 유출이 빠르게 일어나 첨두 유량에 도달하는 시간이 짧고, 강우량이 적을 시에는 첨두 유량의 출현시간이 늦어지는 것을 볼 수 있었다.

• 상하수도학회지
• /
• 제29권2호
• /
• pp.261-269
• /
• 2015

In this study, we applied a membrane distillation process to investigate a feasibility of treating a wastewater with high concentration of organic matters including nitrogen and phosphorus. The laboratory scale experiment was performed by using a hydrophobic PVDF membrane with the pore size of $0.22{\mu}m$ and porosity of 75%. The installation was direct contact type where the temperature difference between a feed and permeate side was controlled to have a range from 20 to $60^{\circ}C$. We observed a flux variation and a concentration changes of COD, $PO{_4}^{3-}$-P, $NH_4{^+}$-N and conductivity of feed side as well as permeate side with various temperature differences (20 to $60^{\circ}C$), cross flow velocities (0.09 to 0.27 m/s) through the module, and pH (6.6 to 12.0) of the feed that has the initial concentration of COD about 1,000 mg/L, total nitrogen 390 mg/L, total phosphorus 10 mg/L, conductivity of $7,000{\mu}s/cm$. The results showed that the average flux was ranged from 4 to $40L/m^2/hr$ which was almost similar with the flux of NaCl and deionized water used as a feed solution. The lowest flux was obtained at the operating condition with the temperature difference of $20^{\circ}C$ and cross flow velocity of 0.09 m/s while the highest one was measured with $60^{\circ}C$ and 0.27 m/s. Above 99% of COD and $PO{_4}^{3-}$-P in the feed could be rejected regardless of an operating condition. However, the removal rate of ammonium nitrogen was varied from 64 to 99% depending on the pH of feed solution.

• 한국미생물·생명공학회지
• /
• 제16권2호
• /
• pp.92-97
• /
• 1988

Proteus mirabilis로부터 glutathione 분해에 관여하는 cysteinylglycine 분해효소를 정제하고 그 성질을 검토하였다. 본 균이 생산하는 cysteinylglycinase의 정제는 무세포추출액에 비해 비활성이 16배 증가하였고 0.68%의 낮은 수율을 나타내었다. Cysteinylglycinase는 (NH$_4$)$_2$SO$_4$침전과정에서 활성을 크게 손실하는 등 정제과정에서 불안정하였으며 투석중에 형성되는 불용성 침전물은 4% Triton X-100 처리에 의해 효과적으로 용해되었다. 본 효소의 일반적 성질은 pH7.3, 온도 35$^{\circ}C$에서 최대 활성을 나타내었다. 열안정성은 5$0^{\circ}C$에서 30분간 열처리에 의해 30%의 활성손실을 보였으며 pH7.0-8.0에서 안정하였다. 이 효소의 분자량은 190.000이었으며 Mn이온과 Mg이온에 의해 활성이 촉진되었고 반응액에 Mg이온을 첨가한 후 30분간 preincubation 하므로서 최대 활성을 보였다. Cysteinylglycine에 대한 Km값과 Vmax 값은 각기 1.60mM과 0.24munit/mg 이었다.

• 통합자연과학논문집
• /
• 제4권2호
• /
• pp.103-112
• /
• 2011

This study was carried out on 4 batch reactors to determine the specific ammonium oxidizing rate (SAOR), specific nitrate forming rate (SNFR) and inhibitory degree of nitrifying activities with saline concentrations. Under salt free condition ammonia was consumed during the reaction period within 200 min. When the salt level increased to 10, 20 and 30 g $NaClL^{-1}$ in reactor, ammonia depletion took 250, 300 and above 350 min, respectively. During concentration above 10 g $NaClL^{-1}$, there was nitrite accumulation. Also, at 30 g $NaClL^{-1}$ ammonia did not depleted and $NO_2{^-}$-N accumulated until the final reaction. Nitrate formation rates decreased with increasing salt concentration. SAOR and SNFR showed a decreasing trend as salinity concentrations were increased. The SAOR was reduced from 0.2 to 0.08 mg $NH_4{^+}$-N $g^{-1}VSS\;day^{-1}$ as the salt concentration increased from 0 to 30 g $NaClL^{-1}$. Similarly, the SNFR decreased from 0.26 kg $NO_3{^-}$-N $kg^{-1}VSS\;day^{-1}$ at saline free to 0.1 kg $NO_3{^-}$-N $kg^{-1}VSS\;day^{-1}$ at saline 30 g L-1. A severe inhibition of nitrifiers activity was observed at increased salt concentrations. The inhibition ratio of specific ammonium oxidation rates were 17, 47 and 60% on the reactor of 10, 20 and 30 g $NaClL^{-1}$ added, respectively. The inhibition ratio of specific nitrate forming rates also were inhibited 30, 53 and 62% on the reactor of 10, 20 and 30 g $NaClL^{-1}$ added, respectively. As the salinity concentrations increased from 0 to 30 mg $NaClL^{-1}$, the average MLSS concentration increased from 1,245 to 1,735 $mgL^{-1}$. The SS concentration of supernatant in reactor which settled about 30 minutes was not severely difference between concentration of salt free reactor and one of those high salt contained reactors.

• Current Research on Agriculture and Life Sciences
• /
• 제14권
• /
• pp.111-122
• /
• 1996

Streptomyces chibaensis J-59 xylanase는 CSL 배지(1% corn steep liquor, 0.15% glucose, 0.1% $MgSO_4{\cdot}7H_2O$, pH 7.0)에서 1% xylan을 효소생산 유도물질로 첨가하였을 경우에 생산(0.83 unit/ml) 되었으나, xylose를 비롯한 각 종 탄소원을 포함하는 배지에서는 효소가 생산되지 않았다. S. chibaensis로 부터 생산된 세포외 xylanase를 $(NH_4)_2SO_4$ 분획침전, DEAE-Sephadex A-50 column chromatography, Sephadex G-200 gel filtration 과정으로 약 29%의 수율로 20배 정제하였다. 정제한 xylanase는 SDS-PAGE 및 Sephadex G-200 gel filtraion에서 분자량이 모두 25,000 Da으로 나타나 monomenc enzyme으로 확인되었다. 금속이온에 대한 영향은 $Fe^{3+}$, $Hg^{2+}$, $Cu^{2+}$, sodium dodecyl sulfate, N-bromosuccinide 등에서는 아주 강한 저해를 받았고, $Mn^{2+}$, $Zn^{2+}$에서는 약간의 저해를 받았다. 반면에 $Mg^{2+}$는 효소활성을 증가시켰다. Xylanase에 의한 xylooligo 당의 생산양상을 TLC로 조사한 결과 xylobiose, xylotriose 및 xylotetrose가 주 생산물이었으며, 반응 1시간 이후부터 소량의 xylose가 생성되었다. 따라서 본 효소는 전형적인 endotype xylanase로 확인되었으며 새로운 기능성식품인 자일로 올리고당(xylooligo-saccharides)의 제조에 이용할 수 있을 것이다.

• 한국토양비료학회지
• /
• 제18권4호
• /
• pp.336-347
• /
• 1985

장항제련소(長項製鍊所)의 배연(排煙)에 영향(影響)을 받는 지역(地域)의 토양(土壤)과 수도(水稻)를 대상(對象)으로 Cd, Cu, Pb 및 Zn등 중금속함량(重金屬含量)을 조사분석(調査分析)한 결과(結果)를 요약(要約)하면 다음과 같다. 1. 제연소(製鍊所)의 배기(排氣)에 의(依)한 오염(汚染)은 동(東)쪽 방향(方向)에서 가장 심(甚)하였고 Pb의 천연부존량(天然賦存量)을 기준(基準)으로 하였을 때 오염거리(汚染距離)는 5km이었으며 표토(表土)에 많이 축적(蓄積)되고 있었다. 2. 토양중(土壤中) 중금속전함량(重金屬全含量)에 대(對)한 0.1N-HCl 및 $N-NH_4Ac$에 의한 용출율(溶出率)은 표토(表土)에서 고도(高度)의 유의성(有意性)있는 상관(相關)을 나타냈다. 3. 토양중(土壤中) 유기물함량(有機物含量) 및 양(陽)ion치환용량(置換容量)과 중금속전함량간(重金屬全含量間)에는 유의성(有意性)있는 상관(相關)을 나타냈다. 4. 제연소주변(製鍊所周邊) 토양(土壤)에서 생산(生産)된 현미중(玄米中)의 중금속함량(重金屬含量)은 Cd가 0.23~1.33, Cu은 2.39~6.25, Pb은 0.95~8.32, Zn은 14.60~27.31ppm이었다. 5. 지상부(地上部) 식물체중(植物體中)의 Cd, Cu 및 Zn의 함량(含量)은 현미중(玄米中) 이들의 함량(含量)과 유의성(有意性) 있는 정(正)의 상관(相關)을 나타내었다. 6. 현미중(玄米中) Cd, Cu, Pb 및 Zn의 함량(含量)은 오염원(汚染源)으로부터 멀리 떨어질수록 감소(減少)하였다.