• Journal of Mushroom
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• v.12 no.4
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• pp.244-250
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• 2014

Phylogenic relationships and morphological characteristics were classified and investigated among the 233 collected strains of Agaricus spp. The 38 strains were differently identified as different characteristic group using analysis of ITS regions in rDNA. A. bitorquis was showed close relationship in groupA whereas A. campestris was in groupC as different characteristic group among with A. bisporus. There was no phylogentic difference with strains collected by country and different pileus colored Agaricus bisporus. Also the strains were cultivated twice to investigate morphological characteristics of fruiting bodies. The characteristics and yield of collected strains were compared with molecular varieties and seasons by the cultivation. In this result, A. campestirs showed good yield and quality in terms of hardness off-white mushroom was more harder than other number of A. bisporus. Also earliness and color of pileus was influenced by external environment all conditions.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.504-511
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• 2016

Lactulose, a synthetic disaccharide, has received increasing interest because of its role as a prebiotic that can increase the proliferation of Bifidobacterium and Lactobacillus spp. and enhance the absorption of calcium and magnesium. While the industrial production of lactulose is still mainly achieved by the chemical isomerization of lactose in alkaline media, this process has drawbacks including the need to remove catalysts and by-products, as well as high energy requirements. Recently, the use of cellobiose 2-epimerase (CE) has been considered an interesting alternative for industrial lactulose production. In this study, to develop a process for enzymatic lactulose production using CE, we screened improved mutant enzymes ($CS-H^RC^E$) from a library generated by an error-prone PCR technique. The thermostability of one mutant was enhanced, conferring stability up to $75^{\circ}C$, and its lactulose conversion yield was increased by 1.3-fold compared with that of wild-type CE. Using a recombinant Escherichia coli strain harboring a CS35 $H^RC^E$-expressing plasmid, we prepared cell beads immobilized on a Ca-alginate substrate and optimized their reaction conditions. In a batch reaction with 200 g/l lactose solution and the immobilized cell beads, lactose was converted into lactulose with a conversion yield of 43% in 2 h. In a repeated 38-plex batch reaction, the immobilized cell beads were relatively stable, and 80% of the original enzyme activity was retained after 4 cycles. In conclusion, we developed a reasonable method for lactulose production by immobilizing cells expressing thermostable CE. Further development is required to apply this approach at an industrial scale.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.232-237
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• 1998

This study was carried out to find the optimal operating conditions for separation of residual uranium from the simulated radwaste solution containing 19 elements, and to evaluate the validity of the process. The selected process was based on the solvent extraction with TBP(tributyl phosphate). As an extractor, two miniature mixer-settlers with a total of 18 stages were used. Extraction yield of U, Np and Tc was about 99.2%. 32.1%, and 99.9%, respectively. The other elements were coextracted in the range of 1~4%. Extraction yield of U exceeded those of the previous work performed with batch system, which resulted in the low extractability of U (about 80%) according to the coexisting element such as Nd and Fe. It was due to the characteristics of multi-stage extractor. On the other hand, low extractability of Np was caused by various oxidation states in the nitric acid medium. In the case of Tc, its high extractability may be attributed to the complex formation with Zr and U, which is not well proved yet. All elements extracted with TBP were stripped into aqueous phase more than 99% by 0.01M $HNO_3$. From the results, this process has no problem with respect to in the same step was required, because Np was distributed in the raffinate and U product, respectively.

• Microbiology and Biotechnology Letters
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• v.37 no.4
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• pp.365-370
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• 2009

For the production of diglyceride (DG) containing medium chain fatty acid, which could be utilized as a substrate to structured lipid production, monoglyceride (MG) and caprylic acid were reacted in the presence of lipase. The reaction system was well mixed homogeneously without using any organic solvent. Among the lipases investigated, Lipozyme RM IM and Novozym 435 were selected on the basis of equilibrium DG yields from the medium chain fatty acid and MG. And reaction conditions such as addition of molecular sieve, water content of immobilized lipase, reaction temperature, and mole ratio of MG/caprylic acid are optimized to increase DG production by using Lipozyme RM IM. DG content of reaction mixture showed 8% increase by adding molecular sieve to reaction mixture. Removal of water from the immobilized lipase could affect seriously equilibrium content of DG. More than 2.8%(w/w) removal of water from the support could make 44% of DG. Optimum temperature was found to $60^{\circ}C$. Temperature shift from $60^{\circ}C$ to $25^{\circ}C$ resulted in increase of free fatty acid (FFA) content. The equilibrium DG yield was not seriously affected by on MG/caprylic acid molar ratio. However, at the stoichiometric ratio of 1:1 the highest DG yield was obtained. Increasing MG/caprylic acid ratio from 0.3 to 1.8 decreased FFA content from 34% to 13%, while MG content increased from 27% to 50%.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.137-141
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• 1979

A study on the processing of soy curd powder with soybean milk and kril autolasate has been carried out to prolong tile self life and to improve the taste and colour of soy curd. The soy curd was manufactured by coagulation of the soybean milk prepared from soybean through a series of processes of soaking, grinding, heating at $500^{\circ}C$ for 5 minutes and filtration. Ten hours was reasonable as the soaking time of the soybean for the high yield of soybean milk. The use of $3\%$ $glucono-\delta-lactone$ to the weight of the raw soybean showed the best coagulation of the soybean milk at $90^{\circ}C$ in relation to the yield and content of crude protein of the soy curd. The soy curd powder prepared by spray drying of soyben milk could be coagulated at $90^{\circ}C$ by the addition of $glucono-\delta-lactone$ after suspending in water. The powder manufactured by spray drying of the mixture of soybean milk and drill autolasate could also be coagulated under the same conditions to produce the soft soy curd. Another powder prepared by spray drying of the mixture of soybean milk, krill autolysate and $glucono-\delta-lactone$ could be coagulated by standing at room temperature after 2 minutes boiling.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.8
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• pp.1140-1150
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• 2009

Forage diets provide good quality carcasses in sheep but very little is known in tropical goats. An experiment was designed with Creole male goats using grass-based systems to assess carcass yield, scores, cuts and composition. After weaning (84 d, 9.2 kg LW) two modes of forage feeding were compared with two replicates of each. Feeding groups were: PF for animals reared at pasture (n = 62) and IF when reared indoors (n = 60). Given that forage finishing will result in low ADG it appeared necessary to study different fattening lengths. The kids were equally divided into 4 groups: group A (n = 32), 4mo after weaning; group B (n = 32), 4mo after A; group C (n = 30), 3mo after B and group D (n = 28), 2mo after C. The animals grazed (in two sub-flocks) on irrigated tropical pastures managed in a rotational system (28 d of re-growth) at a mean stocking rate of 1,200 kg/ha/yr LW. The IF groups were reared in collective pens on a slatted floor (2 replicates of 7 or 8 kids each). They were fed the same stand of tropical grass (25% DM, 12% CP) as that of pasture that was cut daily and provided ad libitum. The ADG (-10%), the weights of omental fat (-60%) and fat in shoulder (-18%), the ultimate pH of carcass (-12%), the meat colour score (-24%), the ""parameter accounting for redness (12%) and the DM and lipid contents (-4%) were significantly lower (p<0.05) in PF than in IF, while the liver was heavier (+23%, p<0.05). Feeding conditions seemed to be similar, thus, differences could be related to gastrointestinal parasitism in the PF system and hypotheses are discussed. Increasing the fattening duration, resulted in significant difference (p<0.01) in many traits: the weights at slaughter and of carcass increased by 40% and 60% from groups A to D and consequently the weights of body compartments and carcass cuts (1.5 to 2.0 fold more). When the results were presented as percentage of empty body weight and carcass weight, these preliminary results (carcass weight 9kg and yield 53%, muscle proportion 70%) and qualitative parameters (low fat score 2/5, fat proportion 5%), seem to be a good incentive for the sector to develop a niche market to meet consumer lean meat expectations. The indoors system could be implemented where there was low availability of grazing areas or problems of dog attacks.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.1-6
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• 1995

An optimal condition for the continuous production of ${\delta}-aminolevulinate$(ALA) was investigated using high concentrated resting cells of Rhodocyclus gelatinosus KUP-74. The increase of the amount of extracellular ALA versus the concentration of resting cells showed rectangular hyperbolic pattern until 20 mg cells/ml, but no further increase in the ALA amount by increasing its concentration was occurred. The highest yield of the extracellular ALA was observed after 3 hr of incubation of 1 ml reaction system containing 20 mg cells, 4 mM levulinate and 5 mM L-glutamate. On the other hand, the immobilized cells prepared by Ca-alginate inclusive method needed to incubate for 6 hr with 6 mM levulinate and 10 mM L-glutamate to give maximal yield of the extracellular ALA. In addition, under these conditions the resulted continuous productivities of the ALA by immobilized cells and highly concentrated resting cells were appeared 50 percent decreases after incubations for 185 hr and 100 hr, respectively, and the method of the cells to be immobilized was more efficient to recover the extracellular ALA produced.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.210-215
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• 2017

This study examined the mechanical design and the structural strength analysis of the rake used in a rotary screener. For the case of the mid-water part, an additional load condition was given by calculating the underwater frictional force generated by the water. For the upper-water part, the analysis was done by dividing the 500kg additional load into the left-concentrated load, center-concentrated load, and right-concentrated load depending on the location of the attached narrow material, and it was determined that all 3 additional load conditions were free from plastic deformation and were secure. The additional load that can occur from the weight of the attached narrow material was divided into three, 1,000kg, 1,300kg, and 1,500kg, and then analyzed. The results of the analysis show that in the case of 1,000kg and 1,300kg, an equivalent strength of 143.6MPa and 186.6MPa occurred, respectively. These figures are lower than the yield strength of the STS304 used in the rotary screener. Therefore, plastic deformation does not occur and is considered to be secure. In the case of 1500kg, however, the equivalent strength that occurred was 215.41MPa, which is greater than the yield strength of STS304, and was judged to be unsafe.

• Microbiology and Biotechnology Letters
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• v.17 no.6
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• pp.568-573
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• 1989

As a way to determine the optimal culture conditions for the production of ${\gamma}$-linolenic acid by Mucor sp. KCTC 8405P, the influence of different carbon and nitrogen sources, initial pH, and C/N ratio of medium was investigated. Glucose was found to be the best carbon source in terms of lipid content and ${\gamma}$-linolenic acid yield. Ammonium sulfate and organic nitrogen sources such as urea and peptone resulted in relatively increased lipid and ${\gamma}$-linolenic acid production. The highest accumulation of lipid was obtained at a C/N ratio of 56.6 using glucose and (NH$_4$)$_2$SO$_4$ as carbon and nitrogen source, respectively. It was found that the lipid content increased significantly with increasing initial pH of medium up to pH 9.0. The influence of mixed carbon source on the ${\gamma}$-linolenic acid yield was also investigated. High accumulation of lipids, 315 mg/100 ml medium, and 13-14% of ${\gamma}$-linolenic acid content in the cellular lipid were obtained in a shaking culture containing 3% of glucose and 2% sodium acetate as carbon source and 0.1% of (NH$_4$)$_2$SO$_4$ as nitrogen source at pH 8.0.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.21-24
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• 1974

Present experiments were conducted to determine the possibility of cultivation of tropical and subtropical saprophytic fungus, Volvariella volvacea (Bull. ex Fr.) Sing. under Korean climatic conditions and the-possibility of applying the method of indoor cultivation which was modified from the cultivation method of the common mushroom, Agaricus bisporus (Lange) Sing.. The results obtained were as follows: 1. In conventional outdoor cultivation, the adequate cultivation period of this fungus was from around the end of June to the end of August. 2. When rice straws submerged in water for 5 days were peak-heated for 6 days in a mush room house, the yield of the fungus was higher than that obtained from the rice straws peak-heated immediately after outdoor composting. 3. The highest yield, 20.49kg per 100kg rice straws, was obtained from the water-soaked and peak-heated rice straws which were cased with a 2 cm layer of loam at 7 days after spawning.