• 한국식품저장유통학회지
• /
• 제6권3호
• /
• pp.333-338
• /
• 1999

김치의 보존성과 품질향상에 미치는 calcium lactate와 calcium acetate의 영향을 조사하기 위하여 calcium lactate와 calcium acetate를 0.5:0-0:0.5의 비율로 혼합하여 김치에 0.5%로 첨가, 1$0^{\circ}C$에서 숙성시키는 동안 pH, 산도, 칼슘함량, 조직의 광학현미경 관찰 및 관능검사를 행하였다. 그 결과 calcium lactate : calcium acetate가 0.4 : 0.1, 0.3 : 0.2, 0.2 : 0.1 비율로 첨가한 김치는 대조구 김치보다 가식한계일이 약 5일정도 연장되었다. 또 김치조직내의 칼슘함량은 46-66%가 증가되었으며 유세포조직의 손상도가 적었으며, 아삭아삭한 조직감과 종합적인 맛이 향상되었다.

• Journal of Microbiology and Biotechnology
• /
• 제14권5호
• /
• pp.914-918
• /
• 2004

This study was carried out to analyze the metabolic flux of W. kimchii sk10 on pyruvate and ethanol as a carbon source. The sk10 grown on ethanol produced acetate under aerobic conditions rather than under anaerobic conditions. The lactate and acetate were produced on ethanol plus pyruvate by the sk10 grown under aerobic and anaerobic conditions, respectively. The resting cell of sk10 produced 99.1 mM acetate and 17.3 mM lactate under aerobic conditions and 51.1 mM acetate and 62.4 mM lactate under anaerobic conditions from ethanol plus pyruvate, respectively. This result is thought to be due to the difference in the $NADH/NAD^+$ ratio depending on the growth conditions. The 11-fold overproduction of NADH peroxidase results in a low $NADH/NAD^+$ratio under aerobic growth conditions. At the low $NADH/NAD^+$ ratio, the metabolic flux of pyruvate toward lactate has to be shifted to a flux toward acetate without NADH oxidation to $NAD^+$, and ethanol oxidation to acetate coupled to $NAD^+$ reduction to NADH has to be activated.

• 한국식품영양학회지
• /
• 제15권4호
• /
• pp.295-299
• /
• 2002

증류주에서 중요한 향미 물질인 에스테르 생성과정을 알아보기 위하여 발효완료 술덧에 알코올과 함께 존재하는 초산, 젖산, 구연산 같은 유기산의 종류별, pH별, 증규 온도별로 에스테르 생성 과정을 실험하였다. 유기산의 종류별 실험에서 생성 에스테르량은 ethyl acetate가 기주에 비해 최고 2.890%, ethyl lactate가 최고 6,410% 린 iso-amyl acetate가 최고 52% 증가하였다. 에스테르차시 pH는 중요한 요인이며, 초산첨가 에스테르화 증류액의 ethyl acetate의 경우 pH 3.0이 pH 4.5보다 2,804% 증가하였고. 젖산 첨가 에스테르화 증류액의 ethyl lactate의 경우 pH 3.0이 pH 4.5보다 1,092% 증가하였다. 에스테르화 증류온도는 초산첨가 에스테르화 가압(약 1.9 기압) 증류액은 상압(1기압) 증류액보다 ethyl acetate 생성은 18% 증가하였고, iso-amyi acetate 생성은 24% 감소하였고, 젖산첨가 데스테르화 가압 증류액은 상압 증류액보다 ethyl-lactate 생성이 33% 증가하였다. 에스테르화 증류시간은 pH 3.0에서는 ethyl acetate 생성은 반응시간 240분으로 충분하고, ethyl lactate 생성은 30된 이상 긴 반응 시간이 필요하였다. 결론적으로 증류주 제조에 있어서 2차 증류시 1차 증류액에 유기산을 첨가하여 증류하면 에스테르량이 증가한 2차 증류액을 얻을 수 있었다.

• 한국동물학회지
• /
• 제15권3호
• /
• pp.101-104
• /
• 1972

간편하고 경제적이며 재현성도 우수한 cellulose acetate 전기영동장치를 제작하였다. 본 장치를 사용하여 몇가지 동물 조직의 lactate 및 malate dehydrogenase isozyme 을 분리 검출하여 본 결과, 기존 제품으로 실험한 결과와 별로 차이가 없음을 알았다. 흔히 cellulose acetate 전기영동은 일정한 정전류에서 실시하는데, 본 장치에서는 약간의 전류변동이 있는 것이 사실이나 실험결과는 충분히 실용적인 것이었다.

• Journal of Microbiology
• /
• 제39권4호
• /
• pp.273-278
• /
• 2001

Shewanela, putrefaciene IR-1 and MR-1 were cultivated by using various combinations electron donor-acceptor, lactate-Fe(III) lactate-nitrate, pyruvate-FE(III), pyruvate-nitrate H$_2$ acetate-Fe(III) and H$_2$-acetate-nitrate. Both strains grew fermentatively on pyruvate and lactate but not on without and electron acceptor. In culture with Fe(III), both astrains grew on pyruvate and lactate but on H$_2$-acetate- CO$_2$. In cultivation with nitrate, both stains grew on pyruvate lactage and on H$_2$-acetate-CO$_2$ The growth yields of IR-1 pyruvate, pyruvate-Fe(III) and lactate-Fe(III) were about 3.4, 3.5, and 3.6(g cell/M substrate), respectively. From the growth properties of both strains on media with Fe(III) as an electron acceptor, the bacterial growth was confirmed not to be increased by addition of Fee(III) as an electron acceptor to the growth medium, which indicates a possibility that the dissimilatory reduction of Fe(III) to Fe(III) may not be coupled to free energy production.

• Asian-Australasian Journal of Animal Sciences
• /
• 제24권2호
• /
• pp.214-221
• /
• 2011

Effects of the cell wall-degrading enzymes derived from Acremonium cellulolyticus and Trichoderma viride on the silage fermentation and in sacco degradation of tropical grasses i.e. rhodesgrass (Chloris gayana Kunth. cv. Callide) and guineagrass (Panicum maximum Jacq. cv. Natsukaze) were investigated in laboratory-scale experiments. These two grasses were either treated with or without the enzymes before ensiling. Untreated rhodesgrass produced acetate fermentation silage (lactate, $13.0\;g\;kg^{-1}$ DM; acetate, $38.7\;g\;kg^{-1}$ DM) with high final pH value and $NH_3$-N content (5.84 and $215\;g\;kg^{-1}$ DM). Addition of enzymes significantly increased (p<0.01) the lactate production (lactate, 45.6; acetate, $34.0\;g\;kg-^{1}$ DM) and decreased (p<0.01) the pH and $NH_3$-N (4.80 and $154\;g\;kg^{-1}$ DM) in the ensiled forages when compared with the control silages. Untreated guineagrass was successfully preserved with a high lactate proportion (lactate, 45.5; acetate, $24.1\;g\;kg^{-1}$ DM), and the addition of enzymes further enhanced the desirable fermentation (lactate, $57.5\;g\;kg^{-1}$ DM; acetate, $19.4\;g\;kg^{-1}$ DM). The content of NDF was lowered (p<0.05) by enzymes in both silages, but the extent appeared greater in the enzyme-treated rhodesgrass (rhodesgrass, $48\;g\;kg^{-1}$ DM; guineagrass, $21\;g\;kg^{-1}$ DM). Changes in the kinetics of in sacco degradation showed that enzyme treatment increased (p<0.01) the rapidly degradable DM (rhodesgrass, 299 vs. $362\;g\;kg^{-1}$ DM; guineagrass, 324 vs. $343\;g\;kg^{-1}$ DM) but did not influence the potential degradation, lag time and degradation rate of DM and NDF in the two silages.

• Journal of Microbiology and Biotechnology
• /
• 제14권5호
• /
• pp.919-923
• /
• 2004

The sk10 isolated from kimchi was identified as W. kimchii on the basis of l6s-rDNA sequencing. Studies were made to analyze the metabolic flux shift of the sk10 on glucose under aerobic growth conditions. The sk10 produced 38.2 mM acetate, 16.3 mM ethanol, and 33.2 mM lactate under aerobic conditions, but 2.4 mM acetate, 48.0 mM ethanol, and 44.1 mM lactate under anaerobic conditions. The NADH peroxidase (NADH-dependent hydrogen peroxidase) activity of sk10 grown under aerobic conditions was 11 times higher than that under anaerobic conditions. Under the low ratio of $NADH/NAD^+$, the metabolic flux toward lactate and ethanol was shifted to the flux through acetate kinase without NADH oxidation. The kinds of enzymes and metabolites of sk10 were close to those in the pathway of Leuconostoc sp., but the metabolites produced under aerobic growth conditions were different from those of Leuconostoc sp. The stoichiometric balance calculated using the concentrations of metabolites and substrate was about 97%, coincident with the theoretical values under both aerobic and anaerobic conditions. From these results, it was concluded that the metabolic flux of W. kimchii sk10 was partially shifted from lactate and ethanol to acetate under aerobic conditions only.

• Journal of Microbiology and Biotechnology
• /
• 제25권7호
• /
• pp.1093-1100
• /
• 2015

Acetate and lactate in growth media are detrimental to the production of Thermus maltogenic amylase (ThMA), a heterologous protein, as well as to the growth of recombinant Escherichia coli. Only 50 mM of acetate or 10 mM of lactate reduced 90% of specific ThMA activity. In this study, mutant E. coli strains blocked in the ackA-pta or ackA-pta and ldh pathways were created, characterized, and assessed for their culture performace in 300 L-scale fermentation. The ackApta and ldh double-mutant strain formed significantly less lactate and acetate, and produced a concomitant increase in the excretion of pyruvate (17.8 mM) under anaerobic conditions. The ackA-pta mutant strain accumulated significant acetate but had an approximately 2-fold increase in the formation of lactate. The ackA-pta and ldh double-mutant strain had superior overall performance in large-scale culture under suboptimal conditions, giving 67% higher cell density and 66% higher ThMA activity compared with those of the control strain. The doublemutant strain also achieved a 179% improvement in volumetric ThMA production.

• Asian-Australasian Journal of Animal Sciences
• /
• 제14권11호
• /
• pp.1560-1563
• /
• 2001

An ability to utilize the substrates (acetate, glucose and lactate) in the lipid synthesis was measured in vitro with the adipose tissues of 4 locations (subcutaneous, SUBC; intramuscular, INTR; tail and kidney, KIDN) in 12 Hanwoo (Korean native cattle) steers (26 and 28 months of ages, mean body weight 638.6 kg). The rates of lipid synthesis from acetate were higher than those from glucose in SUBC and ITRA adipose tissues, respectively. In contrast, the rates of lipid synthesis from glucose were higher than those from acetate in the adipose tissues of tail and KIDN, respectively. Lactate utilization was lowest in all the locations while that of acetate or glucose had the different trends of utilization in the lipogenesis. The rate of lipid synthesis from acetate was highest in the SUBC adipose tissue but was lowest in the KIDN while that from glucose was also higher in the SUBC adipose tissue than in the other tissue locations. The rate of lipid synthesis from lactate, however, was highest in the tail adipose tissue among the locations.

• Environmental Analysis Health and Toxicology
• /
• 제10권1_2호
• /
• pp.15-20
• /
• 1995

The effects of volatile substances inhalation on lactate dehydrogenase and cholinesterase in rats were investigated. Male Sprague-Dawley rats were exposed to marketed odorant, ethyl acetate and ethyl ether for 15 days. Enzyme activities were measured in serum and several tissues such as liver, lung, brain, heart, kidney and muscle to find differences of effects according to the organ. Cholinesterase activity in serum and most of tissues revealed time-dependent decrease in the case of marketed odorant inhalation. Especially in heart and kidney significant decrease was observed. Ethyl acetate exposure to rats revealed also decrease in serum and all tissues by 40% to 60%. Ethyl ether inhalation showed significant decrease by 30% to 50%. Lactate dehydrogenase activity was markedly increased in serum and similarly in heart, brain and kidney by exposure to marketed odorant. No changes were observed in liver. Ethyl acetate exposure to rats revealed increase in serum by about 200%, compared to normal group and in other tissues by 40% to 70% except in liver and muscle. Ethyl ether inhalation showed significant increase in serum by about 100%. There was no change in 'liver and slight increase in muscle.