• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.400-405
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• 2005

Wet-injury often occurs in upland cereals growing in the paddy field due to oxygen deficiency in the rhizosphere caused by excessive water in the soil. Under hypoxia, energy metabolism is diminished causing non­reversible damage to root cells. This study was conducted to investigate effects of hypoxia on root growth and enzymes involved in the fermentative energy metabolism in upland cereals including barley, wheat, rye and triticale. Young seedlings were subject to hypoxia for up to 7 days. Root fresh weight and dry weight were decreased significantly by hypoxia for 5 to 7 days in all cereal seedlings. Root growth retardation under hypoxia was lowest in barley. Hypoxia-induced increases in activity and isozyme expression of alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH) were commonly observed in roots of all cereal seedlings. The inherent ADH activity levels were higher in barley but the hypoxia-induced increases in ADH activities were lowest in barley than other cereals. The inherent LDH activity levels were lower in barley and the hypoxia-induced increases in LDH activities were lower in barley than other cereals. The results suggest the importance of the rapid enhancement of fermentative enzyme systems for increased tolerance to hypoxia.

• Journal of Microbiology and Biotechnology
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• v.29 no.11
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• pp.1749-1759
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• 2019

Aspergillus ochraceus biofilm, developed on an inert support, can produce tannase in Khanna medium containing 1.5% (w/v) tannic acid as the carbon source, at an initial pH of 5.0, for 72 h at 28℃. Addition of 0.1% (w/v) yeast extract increased enzyme production. The enzyme in the crude filtrate exhibited the highest activity at 30℃ and pH 6.0. At 50℃, the half-life (T50) was 60 min and it was 260 min at pH 6.0. In general, addition of detergents and surfactants did not affect tannase activity significantly. Tannase has potential applications in various biotechnological processes such as the production of propyl gallate and in the treatment of tannin-rich effluents. The content of tannins and total phenolic compounds in effluents from leather treatment was reduced by 56-83% and 47-64%, respectively, after 2 h of enzyme treatment. The content of tannins and total phenolic compounds in the sorghum flour treated for 120 h with tannase were reduced by 61% and 17%, respectively. Interestingly, the same A. ochraceus biofilm was able to produce tannase for three sequential fermentative process. In conclusion, fungal biofilm is an interesting alternative to produce high levels of tannase with biotechnological potential to be applied in different industrial sectors.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.189-195
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• 2002

Using Streptomyces sp. YU100 isolated from Korean soil, the fermentative production of phospholipase D was attempted along with its purification and characterization studies. When different carbon and nitrogen sources were supplemented in the culture medium, glucose and yeast extract were found to be the best. By varying the concentration of nutrients and calcium carbonate, the optimal culture medium was determined as 2.0% glucose, 1.5% yeast extract, 0.5% tryptone 0.3% calcium carbonate. During cultivation, the strain secreted most of the phospholipase D in the early stage of growth within 24 h. The phospholipase D produced in the culture broth exhibited hydrolytic activity as well as transphosphatidylation activity on lecithin (phosphatidylcholine). In particular, the culture broth showed 8.7 units/ml of hydrolytic activity when cultivated at $28^{\circ}C$ for 1.5 days. The phospholipase D was purified using 80% ammonium sulfate precipitation and DEAE-Sepharose CL-6B column chromatography, which produced a major band of 57 kDa on a 10% SDS-polyacrylamide gel with purity higher than 80%. The enzyme showed an optimal pH of 7 in hydrolytic reaction, and at pH 4 in a transphosphatidylation reaction. The enzyme activity increased until the reaction temperature was elevated to $60^{\circ}C$. The enzyme was relatively stable at high temperatures and neutral pH, but significantly unstable in the alkaline range. Among the detergents tested as emulsifiers of phospholipids, the highest enzyme activity was observed when 1.5% Triton X-100 was employed. However, no inhibitory effect by metal ions was detected. Under optimized reaction conditions, the purified enzyme not only completely decomposed PC to phosphatidic acid within 1 h, but also exhibited higher than 80% conversion rate of PC to PS by transphosphatidylation within 4 h.

• Korean Journal of Microbiology
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• v.42 no.2
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• pp.160-163
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• 2006

Brown rice contains rice bran and germ with higher nutritional value and dietary fiber content compared with the polished rice. However, brown rice has a limitation of poor digestion. fermented brown rice could be better nutritional source and improve digestibility. Therefore, we tried to select good fermentative microorganisms which have nutritional values with high amylase and protease activities, and probiotic effects. Nineteen micro-organisms, including eight Bacillus strains isolated from Chongkukjang and 11 lactic acid bacteria, were screened for the fermentation ability and enzyme production. The liquid broths containing 2.5%(w/v) of raw brown rice powder as a sole nutritional source were used for culture media. Among the strains tested, all of the Bacillus strains and two lactic acid bacteria (Leuconostoc gelidum and Pediococcus pentosaceus) showed increase in cell population and enzyme activities. The viable cell counts of all the Bacillus strains and two lactic acid bacteria exceeded $10^7 CFU/mL$. The maximal enzyme activities produced by Bacillus sp. Bl, Bacillus sp. B2, Bacillus sp. B11, L. gelidum and P. pentosaceus were 17.85, 17.50, 17.10, 17.10 and 3.24 U/mL for amylase and 22.48, 22.04, 23.76, 12.13, and 3.4 U/mL for pretense, respectively. Therefore, the results of this study demonstrated that the above strains could be potential starters for the fermentation of raw brown rice.

• Journal of Microbiology and Biotechnology
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• v.33 no.12
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• pp.1625-1634
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• 2023

Leuconostoc lactis strain DMLL10 was isolated from kimchi, a fermented vegetable, as a starter candidate through safety and technological assessments. Strain DMLL10 was susceptible to ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, streptomycin, and tetracycline. It did not show any hemolytic activity. Regarding its phenotypic results related to its safety properties, genomic analysis revealed that strain DMLL10 did not encode for any toxin genes such as hemolysin found in the same genus. It did not acquire antibiotic resistance genes either. Strain DMLL10 showed protease activity on agar containing NaCl up to 3%. The genome of DMLL10 encoded for protease genes and possessed genes associated with hetero- and homo-lactic fermentative pathways for lactate production. Finally, strain DMLL10 showed antibacterial activity against seven common foodborne pathogens, although bacteriocin genes were not identified from its genome. These results indicates that strain DMLL10 is a novel starter candidate with safety, enzyme activity, and bacteriocin activity. The complete genomic sequence of DMLL10 will contribute to our understanding of the genetic basis of probiotic properties and allow for assessment of the effectiveness of this strain as a starter or probiotic for use in the food industry.

• Microbiology and Biotechnology Letters
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• v.13 no.1
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• pp.59-64
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• 1985

In order to utilize Citrus peel as fermentative substrate of microorganisms, enzymatic saccharification of Citrus peel by the crude enzyme of Aspergillus sp. GF 015 isolated and identified from nature was investigated. When the fungus was cultured at $27^{\circ}C$ for 3 days in wheat bran medium containing 0.6% $NH_4NO_3$ and 0.05% $KH_2PO_4$, the maximal production of the enzyme was observed. Optimal conditions for enzymatic reaction of crude enzyme were 15ml(97.5 unit)/g of enzyme solution to Citrus peel powder ratio, pH4.0, $45^{\circ}C$ of temperature and 12 hours of reaction time. As the result of saccharifying Citrus peel under optimum conditions, reducing sugar on the weight of dry matter was formed 60.2% and saccharifying rate was 76.3%. The sugar solution obtained were mainly composed of glucose, xylose and galacturonic acid. Hydrolyzing enzymes produced by Aspergillus sp. GF 015 were pectinase, cellulase and xylanase.

• Microbiology and Biotechnology Letters
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• v.19 no.4
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• pp.331-336
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• 1991

In order to utilize natural cellulosic materials as a fermentative substrate, saccharification of a various kind of native cellulosic materials was performed by using cellulase from the isolated strain, Pseudomonas sp. LBC-505 which potently produced cellulase complex and xylanase. Cellulase complex production was repressed by the low concentration of glucose, induced by cellulosic compounds such as CMC, wheat bran and rice straw et al. and showed to be highest on the PY-CMC medium containing 5% (w/v) wheat bran instead of CMC. Optimal temperature for enzyme reactions of CMCase and xylanase was $50^{\circ}C$, and $55^{\circ}C$ for $\beta$-glucosidase. Optimal pH for these enzyme reaction was 6.6. Rate of saccharification for natural cellulose was low by the treatment of crude enzyme. Among their substrates, rice straw was the most effective substrate of enzymatic reaction in this work. After treating rice straw with 5% (v/v) HC1 and hydrolysing with crude enzyme, rate of saccharification was 18.4% (w/w) on dry substrate. Sugars of cellulosic hydrolyzate mainly contained glucose, xylose and cellobiose.

• Microbiology and Biotechnology Letters
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• v.22 no.5
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• pp.499-506
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• 1994

In order to convert starch to the fermentative sugar, the effect of pullulanase on the saccharification of starch and pullulanase was investigated. The optimum pH and temperature for the enzyme activity of the glucoamylase and the crude pullulanase from Klebsiella pneumoniae NFB-320 were shown to be identical as pH 6.0 and 60$\circC, respectively. The crude pullulanase was stable between pH 5.0~6.5, and up to 40$\circC, whereas the glucoamylase was stable between pH 4.0~6.5, and up to 40$\circC. When pullulanase and glucoamylase were engaged together in the sacchrification of starch, saccharification yield was increased by 3.2% than the yield obtained by glucoamylase, alone. And the two enzymes produced sugar from pulltulan 18 times much higher than the single use of pullulanase.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.7
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• pp.998-1003
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• 2016

Although exogenous protease enzymes have been used in poultry diets quite extensively, this has not been the case for pig diets. In general, due to their better gut fermentative capacity and longer transit time, pigs have greater capacity to digest dietary proteins than poultry. However, in early-weaned piglets, the stress brought about by weaning adversely affects the digestion of dietary proteins. Therefore, a study was conducted to determine the effects of a commercial protease enzyme in weanling pigs. Indices of growth, nutrient digestibility, blood profiles, fecal microflora, fecal gas emission and fecal scores were measured during the study. A total of 50 weanling pigs ($6.42{\pm}0.12kg$) at 28 d of age were randomly assigned to receive 1 of 2 dietary treatments: i) control diet (corn-soy based) with no supplemental protease (CON), and ii) control diet+200 g/ton protease (PROT) for 42 d. A completely randomized design consisting of 2 treatments, 5 replicates, and 5 pigs in each replicate was used. Growth performance in terms of body weight ($27.04{\pm}0.38kg$ vs $25.75{\pm}0.39kg$; p<0.05) and average daily gain ($491{\pm}7.40g$ vs $460{\pm}7.46g$; p<0.05) in PROT fed pigs were increased significantly, but gain per feed ($0.700{\pm}0.01$ vs $0.678{\pm}0.01$; p>0.05) was similar between treatments at d 42. Relative to CON pigs, PROT fed pigs had increased (p<0.05) apparent total tract digestibility ($84.66%{\pm}0.65%$ vs $81.21%{\pm}1.13%$ dry matter and $84.02%{\pm}0.52%$ vs $80.47%{\pm}1.22%$ nitrogen) and decreased (p<0.05) $NH_3$ emission ($2.0{\pm}0.16ppm$ vs $1.2{\pm}0.12ppm$) in the feces at d 42. Except for a decreased (p<0.05) in blood creatinine level, no differences were observed in red blood cell, white blood cell, lymphocyte, urea nitrogen, and IgG concentrations between treatments. Fecal score and fecal microflora (Lactobacillus and E. coli) were also similar between CON and PROT groups. Overall, the supplementation of protease enzyme in weanling pigs resulted in improved growth rate and nutrient digestibility. Exogenous protease enzyme reduced fecal $NH_3$ emission, thus, potentially serving as a tool in lowering noxious gas contribution of livestock production in the environment.

• Journal of Veterinary Clinics
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• v.15 no.1
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• pp.156-161
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• 1998

This study investigated the microbiological changes and distribution of bacteria producing enzyme in order to change food wastes to animal feed during 6 days at room temperature. Food wastes were divided as follows: one is untreated food wastes containing 80% water content and another wastes containing 40% water content adiusted by wheat bran. During the fermentation of food wastes, Lactobacillus sp. and Streptococcus sp. were grown the top position among investigated microorganisms in both of food wastes. Numbers of total microorganisms were much more than untreated wastes during fermentation of flood wastes with 40% water content. But, Streptococcus sp. and Enterobacteriaceae from 4 to 6 days were not detected in treated wastes with 40% water contents. This fact indicated that the adiustment of water content in food waste was effective in fermentation. However, the numbers of microorganisms producing pretense were low in both treated and untreated food wastes. These results suggested that flood wastes should be treated as food wastes with 40% water content to maintain a lot of fermentative microorganisms such as Lactobacillus sp., Streptococcus sp. and yeasts together with pretense to make final animal feed.