• Journal of Microbiology and Biotechnology
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• v.29 no.2
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• pp.256-267
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• 2019

The use of low-cost substrates represents one key issue to make single cell oil production sustainable. Among low-input crops, Arundo donax L. is a perennial herbaceous rhizomatous grass containing both C5 and C6 carbohydrates. The scope of the present work was to investigate and optimize the production of lipids by the oleaginous yeast Cutaneotrichosporon curvatus from undetoxified lignocellulosic hydrolysates of steam-pretreated A. donax. The growth of C. curvatus was first optimized in synthetic media, similar in terms of sugar concentration to hydrolysates, by applying the response surface methodology (RSM) analysis. Then the bioconversion of undetoxified hydrolysates was investigated. A fed-batch process for the fermentation of A. donax hydrolysates was finally implemented in a 2-L bioreactor. Under optimized conditions, the total lipid content was 64% of the dry cell weight and the lipid yield was 63% of the theoretical. The fatty acid profile of C. curvatus triglycerides contained 27% palmitic acid, 33% oleic acid and 32% linoleic acid. These results proved the potential of lipid production from A. donax, which is particularly important for their consideration as substitutes for vegetable oils in many applications such as biodiesel or bioplastics.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1144-1148
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• 2001

The implications of incorporating deoiled rice bran (DORB) in diet on the utilization of certain nutrients had been examined through balance studies made with 6- and 10- week-old Japanese quails. The stuffs evaluated in this study had their origin from two different types of processes- a batch extraction (DORB-B) and another continuous process (DORB-C), and each included at 10, 20 or 30% level in an iso-nitrogenous and iso-caloric diet. On chemical analyses, the DORB-B was found to contain crude protein, 19.0; ether extract, 0.79; total ash, 17.05; Ca, 0.11; P, 1.92; glucose, 2.35 and starch 11.22 g/100 g day matter. Corresponding values for DORB-C were 15.02, 1.56, 13.0, 0.40, 2.76, 2.16 and 19.0, respectively. The data on nutrient balances with quails fed diets containing the two-types of DORB suggested no significant (p>0.05) differences in per cent retention of diet dry matter (DM), organic matter (OM), ether extract (EE), gross energy (GE), nitrogen (N), crude fiber (CF), calcium (Ca) or phosphorus (P) content attributable to the extraction process. The age of the birds also appeared to have no significant (p>0.05) effect on nutrient utilization by them. However, the level of inclusion of DORB had a significant (p<0.05) effect on nutrient utilization by quails in that the retention of dietary N, EE, CF, Ca and P was better at lower than at higher levels. It is concluded that the DORB, irrespective of extraction process, can safely be employed upto 20% level in diet of adult Japanese quails without noticeable interference in utilizing the major dietary nutrients.

• Applied Chemistry for Engineering
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• v.5 no.2
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• pp.305-312
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• 1994

The fed-batch process which combinded high selectivity of affinity chromatography and membrane process was developed. The mixture of trypsin and chymotrypsin, having almost the same molecular weight and the chemical structure, were used as model enzymes. The water soluble polymer having more affinity for trypsin and celluose acetate membrane gelated in 50vol.% ethanol for removing free enzymes and retentating trypsin-affinity polymer complex simutaneously were used in this system. The membrane pore size was controlled by ethanol concentration in the gellation bath, and the affinity polymer was prepared by polymerization of acrylamide with N-acryloyl-m-aminobenzamidine at $4^{\circ}C$. The trypsin could be effectively concentrated by utilizing an affinity polymer and a prepared UF-50 ultrafiltration membrane. As a result, 86% purity trypsin was recovered by the current purification process.

• Journal of Environmental Health Sciences
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• v.35 no.3
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• pp.214-219
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• 2009

This study examined the removal efficiency of the nitrogen and phosphorus in order to compensate for the combined process of ATAD(Autothermal Thermophilic Aaerobic Digestion) and EGSB(Expended Granular Sludge Bed), which are treatment methods for livestock wastewater, by introducing SBR(Sequencing Batch Reactor) as post-treatment process. The analysis on the treatment efficiency of each operation mode showed that, in the case of T-N, the treatment efficiency were 67.1% and 74.2% for Run-1 and Run-2, respectively, and in the case of T-P, the values were 71.2 and 74.1, respectively, which are indicating that the treatment efficacy is higher in the condition of Run-1, in which the time period of Anoxic and Aerobic segments were increased. In addition, the result of analyzing removal characteristics of nitrogen and phosphorus by Influx load showed that removal efficiency of nitrogen was better in the case of high influx load than in the case of low influx load. Regardless of Influx load, phosphorus showed constant influx concentration, so that removal efficiency of phosphorus was influenced littler by Influx load than that of nitrogen. This study also fed methanol as an external carbon source and performed experiment to induce denitrification under anoxic condition by using nitrate among nitrogen compounds of SBR reactor, and the results showed that intermittent feeding was more effective in Nitrogen Removal than composite feeding.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.165-172
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• 2006

In order to analyze the bacterial community structure including P-removal related organisms, PAOs(polyphosphate accumulating organisms) and GAOs(glycogen-accumulating non-poly-P organisms) occurred in biological phosphate removing process, 2 reactors(SBR; sequencing batch reactor) were operated on different carbon sources(sodium acetate, glucose). For the analysis of bacterial community structure, molecular methods(FISH: fluorescent in situ hybridization and DGGE; denaturing gel gradient electrophoresis) were employed. After 100 days reaction, $PO_4-P$ in effluent dropped to 3.92 mg/L in SBR #1(60.8% removal) fed by sodium acetate, and at the same time FISH results showed that ${\beta}$-subclass proteobacteria(39.67%) and PAOs(45.10%) were dominantly present whereas those value in SBR #2 fed by glucose was 8.30 mg/L(17% removal), and ${\gamma}$-subclass proteobacteria were considerably observed(23.89%) and PAOs was 21.42%. Also the result of DGGE indicated that ${\beta}$-subclass proteobacteria was dominantly observed in SBR #1. However as the temperature increased, the proportion of ${\beta}$-subclass proteobacteria and PAOs decreased, but phosphorus removing inhibitors(GAOs) increased. It suggests that the environmental factor like as temperature and types of carbon source had influence on the prevalence of phosphorus removing organism(PAOs) and phosphorus removing inhibitors(GAOs) in biological phosphate removing process.

• Journal of Microbiology and Biotechnology
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• v.27 no.6
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• pp.1112-1119
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• 2017

The aim of this study was to develop a potential process for bioethanol production from Hydrodictyon reticulatum (HR), a filamentous freshwater alga, using Saccharomyces cerevisiae (KCTC7017). From the sugar solutions prepared by the four different hydrolysis methods, bioethanol production ranged from 11.0 g/100 g dried material (acid hydrolysis) to 22.3 g/100 g dried material (enzymatic hydrolysis, EH). Bioethanol was fermented from a highly concentrated sugar solution obtained by a decompression-mediated (vacuum) enrichment method (VE). As the results, ethanol was more efficiently produced from HR when sugar solutions were concentrated by VE following EH (EH/VE). Using multiple feeding of the sugar solution prepared by EH/VE from HR, ethanol reached up to a concentration of 54.3 g/l, corresponding to 24.9 g/100 g dried material, which attained the economic level of product concentration (approximately 5%). The results indicate that by using HR, it is feasible to establish a bioethanol production process, which is effective for using microalgae as the raw material for ethanol production.

• KSBB Journal
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• v.19 no.3
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• pp.192-199
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• 2004

In this work the production of glutathione (GSH) by yeast Saccharomyces cerevisiae and the monitoring of the process were studied. In shaking culture the production of GSH was high at initial pH value of 4 and at temperature of 30$^{\circ}C$. But when L-cysteine was added to the culture medium at the beginning of the cultivation, the productivity of GSH was low. In case 0,5% (v/v) of L-cysteine, glycine and glutamic acid were introduced to the culture medium in the exponential cell growth phase, high concentration of GSH (about 90 mg/L) was produced in the bioreactor. A fed-batch operation with stepwise glucose feeding strategy allowed to produce 102 mg/L of GSH. The cultivation processes were on-line monitored by a 2-dimensional fluorescence sensor. A few off-line data such as cell growth, cystein concentration, phosphate concentration and GSH productivity could be well correlated to the fluorescence intensity of some combinations of excitation and emission wavelengths.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1555-1562
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• 2010

Development of the strain and the fermentation process of Hansenula polymorpha was implemented for the production of ${\gamma}$-linolenic acid ($GLA,\;C18:3{\Delta}^{6,9,12}$), an n-6 polyunsaturated fatty acid (PUFA) that has been reported to possess a number of health benefits. The mutated ${\Delta}^6$-desaturase (S213A) gene of Mucor rouxii was expressed in H. polymorpha under the control of the methanol oxidase (MOX) promoter. Without the utilization of methanol, a high-cell-density culture of the yeast recombinant carrying the ${\Delta}^6$-desaturase gene was then achieved by fed-batch fermentation under glycerol-limited conditions. As a result, high levels of the ${\Delta}^6$-desaturated products, octadecadienoic acid ($C18:2{\Delta}^{6,9}$), GLA, and stearidonic acid ($C18:4{\Delta}^{6,9,12,15}$), were accumulated under the derepression conditions. The GLA production was also optimized by adjusting the specific growth rate. The results show that the specific growth rate affected both the lipid content and the fatty acid composition of the GLA-producing recombinant. Among the various specific growth rates tested, the highest GLA concentration of 697 mg/l was obtained in the culture with a specific growth rate of 0.08 /h. Interestingly, the fatty acid profile of the yeast recombinant bearing the Mucor ${\Delta}^6$-desaturase gene was similar to that of blackcurrant oil, with both containing similar proportions of n-3 and n-6 essential fatty acids.

• Journal of Microbiology and Biotechnology
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• v.27 no.7
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• pp.1281-1287
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• 2017

Bone morphogenetic protein-4 (BMP-4) is considered to have therapeutic potential for various diseases, including cancers; however, the high expression of biologically active recombinant human BMP-4 (rhBMP-4) needed for its manufacture for therapeutic purposes has yet to be established. In the current study, we established a recombinant Chinese hamster ovary (rCHO) cell line overexpressing rhBMP-4 as well as a production process using 7.5-l bioreactor (5 L working volume). The expression of the mature rhBMP-4 was significantly enhanced by recombinant furin expression. The combination of a chemically defined medium and a nutrient supplement solution for high expression of rhBMP-4 was selected and used for bioreactor cultures. The 11-day fed-batch cultures of the established rhBMP-4-expressing rCHO cells in the 7.5-L bioreactor produced approximately 32 mg/l of rhBMP-4. The mature rhBMP-4 was purified to homogeneity from the culture supernatant using a two-step chromatographic procedure, resulting in a recovery rate of approximately 55% and a protein purity greater than 95%. The N-terminal amino acid sequences and N-linked glycosylation of the purified rhBMP-4 were confirmed by N-terminal sequencing and de-N-glycosylation analysis, respectively. The mature purified rhBMP-4 has been proved to be functionally active, with an effective dose concentration of $EC_{50}$ of 2.93 ng/ml.

• Microbiology and Biotechnology Letters
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• v.26 no.6
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• pp.537-544
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• 1998

The cultivation conditions of transformant Alcaligenes eutrophus AER5 harboring cloned phbC gene for mass production of poly (3-hydroxybutyrate-3-hydroxyvalerate)[P(3HB-3HV)] containing high molar fraction of 3-hydroxyvalerate (3-HV) were investigated. In two-stage batch cultivation, transformant accumulated P(3HB-3HV) containing 52.2 mol% of 3HV compared to 30 mol% of parent strain A. eutrophus H16. The increased 3-HV molar fraction was due to the amplified activity of PHB synthase participating in condensation of 3-HB and 3-HV. To increase efficiency of P(3HB-3HV) accumulation, fructose was added along with precursor compound valerate, and total cell mass and P(3HB-3HV) concentrations remarkably increased, but not 3-HV molar fraction. The effect of magnesium ion showed that P(3HB-3HV) concentration and 3-HV molar fraction were significantly increased upto 6.1 g/L and 71.3 mol% at 0.01 g/L of MgSO$_4$, respectively. The efficiency of several pH adjuster, NaOH, NaOH and (NH$_4$)$_2$SO$_4$, and NH$_4$OH, on total cell mass, p(3HB-3HV) concentration, and 3-HV molar fraction was also compared. To overcome the disadvantage of two-stage cultivation, one-stage intermittent fed-batch cultivation was attempted, such a way 10.0 g/L of fructose was supplied for cell growth at initial 36 hr and then 10.0 g/L of valerate and 5.0 g/L of fructose were applied to induce the accumulation of P(3HB-3HV), consequently, 10.4 g/L of P(3HB-3HV) with 38 mol% of 3-HV fraction could be obtained after 72 hr. These results can be used for elucidating cultivation strategy for mass production of P(3HB-3HV) containing high 3-HV molar fraction using transformant A. eutrophus AER5 harboring cloned phbC gene.