• Asian-Australasian Journal of Animal Sciences
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• 제28권11호
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• pp.1624-1628
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• 2015

Rigorously standardized laboratory protocols are essential for meaningful comparison of data from multiple sites. Considering that interactions of minerals with organic matrices may vary depending on the material nature, there could be peculiar demands for each material with respect to digestion procedure. Acid digestion procedures were evaluated using different nitric to perchloric acid ratios and one- or two-step digestion to estimate the concentration of calcium, phosphorus, magnesium, and zinc in samples of carcass, bone, excreta, concentrate, forage, and feces. Six procedures were evaluated: ratio of nitric to perchloric acid at 2:1, 3:1, and 4:1 v/v in a one- or two-step digestion. There were no direct or interaction effects (p>0.01) of nitric to perchloric acid ratio or number of digestion steps on magnesium and zinc contents. Calcium and phosphorus contents presented a significant (p<0.01) interaction between sample type and nitric to perchloric acid ratio. Digestion solution of 2:1 v/v provided greater (p<0.01) recovery of calcium and phosphorus from bone samples than 3:1 and 4:1 v/v ratio. Different acid ratios did not affect (p>0.01) calcium or phosphorus contents in carcass, excreta, concentrate, forage, and feces. Number of digestion steps did not affect mineral content (p>0.01). Estimated concentration of calcium, phosphorus, magnesium, and zinc in carcass, excreta, concentrated, forage, and feces samples can be performed using digestion solution of nitric to perchloric acid 4:1 v/v in a one-step digestion. However, samples of bones demand a stronger digestion solution to analyze the mineral contents, which is represented by an increased proportion of perchloric acid, being recommended a digestion solution of nitric to perchloric acid 2:1 v/v in a one-step digestion.

• 한국환경과학회지
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• 제9권1호
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• pp.75-80
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• 2000

Kinetic data for the acid phase anaerobic digestion were presented in this study and the constants were determined with acid production rate and gas production rate. Process models based on continuous culture theory were used to describe the characteristics of the acid forming microorganisms and to enable further development toward utilization of the process in a more rational manner. Acid phase digestion can be separated with appropriate manipulation of hydraulic retention time in anaerobic digestion. Kinetic analysis of data from the various hydraulic retention times using a phase specific model obtained form the acid phase indicated maximum specific growth rate of 0.40/h, saturation constant of 2,000mgCOD.$\ell$, yield coefficient of 0.35 mgVSS/msCOD utilized and decay constant of 0.04/h for the acid production rate. Similar analysis of data for the gas production rate indicated maximum specific growth rate of 0.003/h, saturation constant of 2,200mgCOD/$\ell$, yield coefficient of 0.035 mgVSS/mgCOD utilized and decay constant of 0.06/h.

• 한국환경과학회지
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• 제15권9호
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• pp.897-905
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• 2006

This study has been conducted to investigate biodegradation characteristics and optimum mixing ratio for co-digestion with thermophilic acid-fermented food waste and sewage sludge using batch anaerobic digester. As the basis operating conditions for anaerobic digestion, the reaction temperature was controlled $35{\pm}1^{\circ}C$ and stirrer was set 70rpm. Thermophilic acid-fermented food waste and sewage sludge were mixed at the ratio of 10:0, 7:3, 5:5, 3:7, 0:10 and 5;5(food waste : sewage sludge) as the influent substrates. In results of co-digestion according to mixing ratio of thermophilic fermented food wastes and sewage sludge in batch mesophilic anaerobic digestion reactor, $385mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio was more than that of any other mixing ratios. Compared with $293mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio of food wastes and sewage sludge, pretreatment of food wastes by thermophilic acid fermentation was more effective in co-digestion with sewage sludge.

• 한국축산식품학회지
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• 제33권6호
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• pp.689-695
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• 2013

This study was conducted to investigate the effects of in vitro human digestion on the antioxidant activity of blueberry leaf extracts (BLE) in emulsion-type sausages (ETS). Leaves from four cultivars of blueberries (Bluecrop, Bluegold, Duke, and Northland) collected from a wild blueberry farm were extracted with 80% ethanol. ETS were prepared with 0.2% BLE. The samples were then passed through an in vitro human digestion system which simulates the composition of the mouth, stomach, and small intestine juice. Only one phenolic compound (chlorogenic acid) was detected in the BLE. Northland BLE had appreciably higher amounts of chlorogenic acid than that of other BLE, both before and after in vitro human digestion. Antioxidant activity of any BLE was not influenced by in vitro human digestion, whereas the antioxidant activity of chlorogenic acid standard increased in response to in vitro human digestion in both 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric-reducing ability of plasma (FRAP). In the present study, the antioxidant activities of the BLE were not strongly influenced by in vitro human digestion, and the antioxidant activity depended on the chlorogenic acid content of ETS. Thus, compounds from blueberry leaves may have important applications in the future as natural antioxidants for meat products.

• 펄프종이기술
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• 제43권1호
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• pp.65-73
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• 2011

The fibrous raw materials in packaging-grade paper production in Korea were mainly obtained from waste paper. The use of recycled paper has both positive and negative impacts in papermaking process. The primary positive impacts are the environmental protection and manufacturing cost reduction, and the negative impacts are the quality reduction in paper quality and the accumulation of heavy metals and other pollutants in wet- and dry-end process. This study was carried out to consider the optimum acid decomposition system with the highest recovery rate for the analysis of heavy metals in packaging-grade paper. The open digestion system using Kjeldahl apparatus and the closed digestion system using microwave oven for decomposing the organic materials in paper were compared. In both open and closed digestion method, the combination of nitric acid, hydrochloric acid and hydrogen peroxide showed higher recovery rate than using only nitric acid alone because the presence of Cl- ions in hydrochloric acid stabilizes ligand formation with metal ions. KOCC was observed to have the highest heavy metal content among the recycled paper samples. The heavy metal contents decomposed with the closed digestion system were relatively higher than with open digestion system.

• Asian-Australasian Journal of Animal Sciences
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• 제3권1호
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• pp.27-31
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• 1990

Influences of plant phenolic acids and their possible metabolites(non-phenolic aromatic acids involved) in the rumen on the cellulolytic activity of mixed rumen populations were examined by a simple in vitro culture technique. Initial concentrations of aromatic acids were 1, 5, 10 and 20 mM/l. All the tested aromatic acids reduced microbial cellulose digestion especially at the higher initial concentration. P-Coumaric acid, ferulic acid and cinnamic acid, those having unhydrogenated propenoic side chain were more inhibitory than were 3-phenylpropinic acid and phloretic acid, those having hydrogenated propanoic side chain. Lag-time for cellulose digestion was prolonged by former three acids by 16 h. Apparent reduction in p-coumaric acid concentration was observed at 24 h when cellulose digestion began. Volatile fatty acid productions from cellulose fermentation were shifted by former three aromatic acids to produce more acetate and less propionate. This suggests that the selection of celluloytic organisms was induced by these aromatic acids.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2000년도 추계학술대회
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• pp.298-301
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• 2000

Heavy metals are extracted from stream sediments, roadside soils and sediments and soils and tailings from mining area using partial extraction, acid digestion and HF-digestion. Compared to amounts of heavy metals extracted using partial extraction, those extracted using acid digestion are higher by 2.0∼220.9 times in Cu, 2.4∼2806.1 times in Pb, 1.3∼121 times in Cd, 14.1∼1300885 times in Fe, 1.2∼271.5 times in Mn, 1.3∼372.5 times in Zn, 2.2∼1734.5 times in Cr. Although partial extraction, which extracts less amounts of heavy metals from soil compared to acid digestion, is used in domestic standard method for examination of soil, domestic soil standard for heavy metals in non-agricultural and industrial areas is higher than soil standard in foreign countries which use acid digestion, For improvement of the domestic standard method for assessment of soil, it is suggested to lower the domestic soil standard for heavy metals or to change pretreatment method for extracting heavy metals from partial extraction to acid digestion with modifying the soil standard.

• 분석과학
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• 제16권2호
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• pp.152-158
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• 2003

본 연구는 인체의 골중 납 농도를 측정하는데 필요한 시료 전처리법과 기기 분석법을 평가하기 위하여 수행되었다. 절단한 인간 사체 다리의 뼈를 상온에서의 산 분해법과 마이크로웨이브 분해법 (microwave oven method)을이용하여 납을 추출하였으며, 유도결합 플라즈마 질량분석법 (ICP-MS)과 흑연로 원자 흡수 분광 광도법 (GF-AAS)으로 납 농도를 측정하였다. 표준시료를 이용하여 회수율을 조사한 결과, 산분해 후 ICP-MS로 측정한 경우 높은 회수율을 보였으나, 산분해 후 GF-AAS로 측정한 것은 표준 농도보다 낮은 값을 보였으며, 마이크로웨이브 분해한 경우는 두 측정기기 모두 표준 농도보다 높은 값을 보였다. 뼈 시료의 경우, 산분해 후 ICP-MS로 측정한 납 농도는 GF-AAS의 값과 높은 상관성을 보였으나 (상관계수 = 0.983), GF-AAS가 ICP-MS보다 계통적으로 높은 값을 측정하였다. 마이크로웨이브 분해 역시 두 분석방법이 높은 상관성을 보였으나 (상관계수 = 0.950), 대체로 산분해에 의한 값보다 높은 농도를 보였다. 결론적으로, 상온에서 질산으로 분해 후 ICP-MS를 이용하여 측정한 것이 골중 납 농도를 결정하는데 편이성과 정확성 면에서 가장 효율적인 방법으로 보인다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권1호
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• pp.63-83
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• 2001

하천, 고속도로 주변, 광산지역으로부터 채취된 시료를 대상으로 용출법과 산분해법, 완전용해법의 세가지 전처리 방법을 적용하여 중금속을 추출하고 그 결과를 비교하였다. 전처리방법으로 용출법 사용시 중금속 추출량에 비해 산분해법 사용시의 중금속 추출량이 Cu는 2.0∼221배, Pb는 2.4∼2806배, Cd는 1.3∼121배, Fe는 14.1∼1300885배, Mn은 1.2∼272배, Zn은 1.3∼373배, Cr은 2.2∼1735배 높게 나타났다. 용출법에 의한 중금속 추출량과 산분해법에 의한 중금속 추출량간에 특별한 상관관계가 없다. 이에 반해 산분해법 사용시 중금속 추출량과 완전용해법 사용시 중금속 추출량간에는 다소 상관관계가 있을 가능성이 있다. 국내와 국외의 비농경지 및 공장·산업지역 토양오염 기준치를 비교하여 볼 때 중금속(Cd, Cu, Pb)이 상대적으로 적게 추출되는 용출법을 사용하는 국내의 기준치가 중금속이 상대적으로 많이 추출되는 산분해법을 사용하는 외국의 기준치 보다 낮아야 함에도 불구하고 국내의 기준치가 외국보다 대부분 높게 책정되어있다. 개선책으로 용출법을 계속 적용하되 기준치를 낮추거나 아니면 전처리방법을 산분해법으로 바꾸고 기준치를 재조정하는 것이 필요하다.

• 한국환경과학회지
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• 제30권12호
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• pp.1093-1100
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• 2021

The present study investigated the effect of ammonia load on microbial communities in mesophilic anaerobic digestion of propionic acid. A laboratory-scale continuous anaerobic digester treating propionic acid as a sole organic substrate was operated under non-inhibitory condition and inhibitory conditions with ammonia (1.5 g and 3.5 g ammonia-N/L, respectively), and bacterial and archaeal communities in the steady states of each ammonia condition were analyzed using high-throughput sequencing. Thirteen bacterial families were detected as abundant bacterial groups in mesophilic anaerobic digestion of propionic acid. Increase in ammonia concentration resulted in significant shifts in microbial community structures. Syntorophobacter, Pelotomaculum, and Thermovigra were determined as the dominant groups of (potential) propionate oxidizing bacteria in the non-inhibitory condition, whereas Cryptanaerobacter and Aminobacterium were the dominant groups of (potential) propionate oxidizing bacteria in the ammonia-inhibitory condition. Methanoculleus and Methanosaeta were the dominant methanogens. Acetate-oxidation coupled with hydrogenotrophic methanogenesis might be enhanced with increases in the relative abundances of Methanoculleus and Tepidanaerobacter acetatoxydans under the ammonia-inhibitory condition. The results of the present study could be a valuable reference for microbial management of anaerobic digestion systems that are exposed to ammonia inhibition and propionic acid accumulation.