• 한국미생물·생명공학회지
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• 제21권5호
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• pp.511-512
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• 1993

The production of vinegar containing high acetic acid concentration was carried in a single stage fed-batch culture. The initial and residual ethanol concentration were 50.0g/l and 5.0g/l, respectively, and the ethanol concentration was maintained from 5.0g/l to 10.0g/l during fedbatch culture. The fermentation temperature was decreased by 1C for every increase of 2.0% in acidity. The maximum productivity was 2.53g/l-hr and the acidity was 16.08% after 40 hours of acetic acid fermentation.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.603-606
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• 2005

Ralstonia eutropha NCIMB 11599 and ATCC 17699 were grown, and their productions of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] compared. In flask cultures of R. eutropha NCIMB 11599, cell concentration, P(3HB-co-4HB) concentration and polymer content decreased considerably with increases in the ${\gamma}-butyrolactone$ concentration, and the 4HB fraction was also very low (maximum 1.74 mol%). In fed-batch cultures of R. eutropha NCIMB 11599, glucose and ${\gamma}-butyrolactone$ were fed as the carbon sources, under a phosphate limitation strategy. When glucose was fed as the sole carbon source, with its concentration controlled using an on-line glucose analyzer, 86% of the P(3HB) homopolymer was obtained from 201g/L of cells. In a two-stage fed-batch culture, where the cell concentration was increased to 104g/L, with glucose fed in the first step and constant feeding of ${\gamma}-butyrolactone$, at 6g/h, in the second, final cell concentration at 67h was 106g/L, with a polymer content of 82%, while the 4HB fraction was only 0.7mol%. When the same feeding strategy was applied to the fedbatch culture of R. eutropha ATCC 17699, where the cell concentration was increased to 42 g/L, by feeding fructose in the first step and ${\gamma}-butyrolactone$ (1.5g/h) in the second, the final cell concentration, polymer content and 4HB fraction at 74h were 51g/L, 35% and 32 mol%, respectively. In summary, R. eutropha ATCC 17699 was better than R. eutropha NCIMB 11599 in terms of P(3HB-co-4HB) production with various 4HB fractions.

• 상하수도학회지
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• 제16권6호
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• pp.670-678
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• 2002

Since Korean government imposed a stricter regulation on effluent T-N and T-P concentrations from wastewater treatment plant, a new process has to be developed to meet these rules and this process should remove T-N and T-P, economically, from weak wastewater that is typical for Korea's combined sewer system sewage. In this study, a computer simulator, BioWin from EnviroSim, Inc. was used. Three processes - A2/O, Modified Johannesburg, UCT- had been simulated under same operational conditions and a new process - Parallel BNR Process - had been developed based on these simulation results. The Parallel BNR process consists of two rows of reactors: One row has anaerobic and aerobic reactors in series, and the other row has RAS anoxic1 and RAS anoxic2 reactors in series. In order to ensure anaerobic state in anaerobic tank, a part of influent is fed to RAS anoxic1 tank in second row. This process had been simulated under same conditions of other three processes and the simulation results were compared. The results showed that three existing processes could not perform biological phosphorus removal when the average influent was fed at any operation temperatures. However, the Parallel BNR process was found that biological phosphorus removal could be performed when both design and average influent were fed at any operation temperatures. This process showed the T-N concentration in effluent had a maximum value of 15mg/L when design influent was fed at $13^{\circ}C$ and a minimum value of 14mg/L when average influent was fed at $20^{\circ}C$. Also, T-P concentrations had a maximum value of 1.3mg/L when average influent was fed at $20^{\circ}C$ and a minimum value of 1.1mg/L when design influent was fed at $13^{\circ}C$. Based on these results, we found that this process can remove nitrogen and phosphorus biologically under any operational conditions.

• Journal of Microbiology and Biotechnology
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• 제17권1호
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• pp.116-122
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• 2007

An efficient enzyme system for the synthesis of L-tyrosine was developed using a fed-batch reactor with continuous feeding of phenol, pyruvate, and ammonia. A thermo- and chemostable tyrosine phenol-lyase from Symbiobacterium toebii was employed as the biocatalyst in this work. The enzyme was produced using a constitutive expression system in Escherichia coli BL21, and prepared as a soluble extract by rapid clarification, involving treatment with 40% methanol in the presence of excess ammonium chloride. The stability of the enzyme was maintained for at least 18 h under the synthesis conditions, including 75 mM phenol at pH 8.5 and $40^{\circ}C$. The fed-batch system (working volume, 0.51) containing 1.0 kU of the enzyme preparation was continuously fed with two substrate preparations: one containing 2.2 M phenol and 2.4 M sodium pyruvate, and the other containing 0.4 mM pyridoxal-5-phosphate and 4M ammonium chloride (pH 8.5). The system produced 130g/I of L-tyrosine within 30h, mostly as precipitated particles, upon continuous feeding of the substrates for 22 h. The maximum conversion yield of L-tyrosine was 94% on the basis of the supplied phenol.

• KSBB Journal
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• 제13권2호
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• pp.203-208
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• 1998

We investigated the effects of dissolved oxygen (D.O.) and fructose (C-source) on cell growth and biosynthesis of cyclosporin A (CyA) produced as a secondary metabolite by a wild-type filamentous fungus, Tolypocladium inflatum. This was performed by controlling the level of D.O. and the residual C-source, as required, through adjustment of medium flow rate, medium concentration and agitation rate in fed-batch cultures. CyA production was furned out to be maximal, when D.O. level was controlled around 10% saturated D.O. and concentration of the C-source was maintained sufficiently low (below 2 g/L) not to cause carbon catabolite repression. Under this culture condition, we obtained the highest values of CyA concentration (507.14 mg/L), Qp (2.11 mg CyA/L/hr), $Y_x/s$ (0.49 g DCW/g fructose), $Y_p/s$<(22.56 mg CyA/g fructose), and YTEX>$_p/x$ (48.31 mg CyA/g DCW), but relatively lower values of cell concentration (11.98 g DCW/L) and cell productivity (0.043 g DCW/L/hr), in comparison with other parallel fed-batch fermentation conditions. These results implied that, in the carbon-limited culture with 10% saturated D.O. level, the producer microorganism utilized the C-source more efficiently for secondary metabolism.

• Journal of Microbiology and Biotechnology
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• 제20권11호
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• pp.1534-1538
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• 2010

Fed-batch cultures of Hansenula polymorpha were studied to develop an efficient biosystem to produce recombinant human serum albumin (HSA). To comply with this purpose, we used a high-purity oxygen-supplying strategy to increase the viable cell density in a bioreactor and enhance the production of target protein. A mutant strain, H. polymorpha GOT7, was utilized in this study as a host strain in both 5-l and 30-l scale fermentors. To supply high-purity oxygen into a bioreactor, nearly 100% high-purity oxygen from a commercial bomb or higher than 93% oxygen available in situ from a pressure swing adsorption (PSA) oxygen generator was employed. Under the optimal fermentation of H. polymorpha with highpurity oxygen, the final cell densities and produced HSA concentrations were 24.6 g/l and 5.1 g/l in the 5-l fermentor, and 24.8 g/l and 4.5 g/l in the 30-l fermentor, respectively. These were about 2-10 times higher than those obtained in air-based fed-batch fermentations. The discrepancies between the 5-l and 30-l fermentors with air supply were presumably due to the higher contribution of surface aeration over submerged aeration in the 5-l fermentor. This study, therefore, proved the positive effect of high-purity oxygen in enhancing viable cell density as well as target recombinant protein production in microbial fermentations.

• 한국식품영양과학회지
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• 제42권10호
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• pp.1567-1575
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• 2013

본 연구에서는 유황오리의 우수성을 확인하기 위하여 유황오리, 일반오리, 닭을 열수추출 하여 유황오리의 대장염 염증에 대한 억제 효과를 알아보고자 하였다. Balb/c 수컷 마우스에 2.5% DSS로 궤양성 대장염을 유도하였고 이에 대한 대장염의 염증 억제효과를 검토하였다. 모든 실험군 중에서 정상군의 대장 길이가 가장 길었고, 대조군의 대장 길이가 가장 짧았다. 유황오리 고농도군, 저농도군의 대장의 길이는 일반오리 고농도군 저농도군의 대장 길이보다 길었으며, 닭고농도군, 저농도군의 대장의 길이는 일반오리 추출물보다 짧았다. 유황오리 저농도군에서 대장 길이가 시료처리군 중에서 가장 길었고, 대장염 증상의 개선 효과를 나타내었다. 대장의 조직학적 관찰에서 대장의 길이의 축소 정도가 증가함에 따라 대장조직의 점막층의 선와부의 손실이 증가되었다. 대장염 염증 초기에 증가하는 염증성 biomarker인 혈청 IL-$1{\beta}$, IL-6, TNF-${\alpha}$, IL-17A, IL-12의 생성은 유황오리 저농도군에서만 대조군보다 유의적으로 감소하였고, 정상군과 비슷한 수준을 보였다(P<0.05). 대장염을 일으킨 대장조직에서의 염증성인자인 IL-6, TNF-${\alpha}$, COX-2, iNOS의 mRNA 발현에서도 유황오리 추출액이 일반오리 추출액보다 더 많이 감소하였고, 유황오리 저농도군에서 가장 많이 감소되었다. 이상의 결과로 DSS로 대장염이 유도된 마우스에서 유황오리 추출액이 일반오리와 닭 추출액보다 더 높은 항염증 효과를 나타내었고 처리 농도에 따른 차이가 있었으며, 유황오리 추출액을 1 mL/kg으로 투여하였을 때 대장의 염증을 억제하는 효과가 가장 우수하였다.

• 한국수산과학회지
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• 제35권4호
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• pp.336-341
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• 2002

본 연구는 치어기 잉어에 있어서 어분 (fish meal, FM) 대체 단백질원으로서 lysine 부산물 (lysine cell mass, LCM)이 사료내 이용 가능성과 대체 수준을 결정하기 위해 수행하였다. 실험사료의 조단백질 함량은 $38\%$, 가용에너지는 15.2kJ/g (protein, carbohydrate and lipid: 16.7, 16.7 and 37.7kJ/g)으로 동일하게 맞추어 실험사료를 제조하였으며, 사료의 조성을 요약하면 다음과 같다: $100\%$ $FM; LCM_20$, $80\%$ $FM+20\%$ $LCM; LCM_40$, $60\%$ $FM+40\%$ $LCM; LCM_60$, $40\%$ $FM+60\%$ $LCM; LCM_100$, $100\%$ $LCM; LCM_20$l, $80\%$ $FM+20\%$ $LCM+0.07\%$ $Lysine; LCM_40$l, $60\%$ $FM+40\%$ $LCM+0.14\%$ $Lysine; LCM_60$l $40\%$ $FM+60\%$ $LCM+0.22\%$ $Lysine; LCM_100$l, $100\%$ $LCM+0.35\% Lysine. 6주 동안의 실험 결과, 증체율, 사료효율, 일간성장률, 간중량지수 및 단백질전환효율에 있어서 LCM_0와 비교하석 LCM_20는 유의적인 차이가 없는 반면에 (P>0.05), $LCM_40,\;LCM_60$ 및 $LCM_100,\;LCM_40l,\;LCM_60$l 및 $LCM_100$l는 유의적으로 낮게 나타났다 (P<0.05). $LCM_0$와 $LCM_20$l은 증체율, 일간성장률, 간중량지수 및 단백질 전환효율에 있어서는 유의적인 차이를 보이지 않는 반면에 (P>0.05), 사료효율에 있어서는 $LCM_0$에 비해 $LCM_20$l이 유의적으로 낮게 나타났다 (P<0.05). 헤마토그리트과 비만도는 모든 사료구에서 유의적인 차이가 없었다 (P<0.05). 따라서, 치어기 잉어에 있어서 Iysine 부산물은 어분단백질의 $100\%$ $FM; LCM_20$, $80\%$ $FM+20\%$ $LCM; LCM_40$, $60\%$ $FM+40\%$ $LCM; LCM_60$, $40\%$ $FM+60\%$ $LCM; LCM_100$, $100\%$ $LCM; LCM_20$l, $80\%$ $FM+20\%$ $LCM+0.07\%$ $Lysine; LCM_40$l, $60\%$ $FM+40\%$ $LCM+0.14\%$ $Lysine; LCM_60$l $40\%$ $FM+60\%$ $LCM+0.22\%$ $Lysine; LCM_100$l, $100\%$ $LCM+20\%까지 대체 가능하며, lysine 부산물에 결핍된 필수아미노산인 lysine을 첨가한 사료구에서는 첨가 효과가 나타나지 않았다.

• Asian-Australasian Journal of Animal Sciences
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• 제22권5호
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• pp.681-685
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• 2009

L-carnitine promotes mitochondrial ${\beta}$-oxidation of long chain fatty acids and their subsequent transport across the inner mitochondrial membrane. Although the role of L-carnitine in fatty acid metabolism has been extensively studied, its role in live performance and carcass responses of commercial broilers is less understood. The objective of this research was to determine if Lcarnitine fed at various levels in diets differing in CP and amino acids impacted on live performance and carcass characteristics of commercial broilers. Two floor pen experiments were conducted to assess the effect of dietary L-carnitine in grower diets. In Exp. 1, Ross${\times}$Hubbard Ultra Yield broilers were placed in 48 floor pens (12 birds/pen) and fed common diets to d 14. A two (0 or 50 ppm Lcarnitine) by three (173, 187, and 202 g/kg CP) factorial arrangement of treatments was employed from 15 to 35 d of age (8 replications/treatment). An interaction (p<0.05) in carcass yield indicated that increasing CP (187 g/kg) resulted in improved yield in the presence of L-carnitine. Increasing CP from 173 to 202 g/kg increased (p<0.05) BW gain and decreased (p<0.05) feed conversion and percentage abdominal fat. Feeding dietary L-carnitine increased back-half carcass yield which was attributable to an increase (p<0.05) in thigh, but not drumstick, yield relative to carcass. In Exp. 2, $Ross{\times}Ross$ 708 broilers were fed common diets until 29 d. From 30 to 42 d of age, birds were fed one of seven diets: i) 200 g/kg CP, 0 ppm L-carnitine; ii) 200 g/kg CP, 40 ppm L-carnitine; iii) 180 g/kg CP, 0 ppm L-carnitine; iv) 180 g/kg CP, 10 ppm L-carnitine; v) 180 g/kg CP, 20 ppm L-carnitine; vi) 180 g/kg CP, 30 ppm L-carnitine; and vii) 180 g/kg CP, 40 ppm L-carnitine (6 replications of 12 birds each). BW gain, feed conversion, mortality (30 to 42 d), and carcass traits (42 d) were measured on all birds by pen. There were no treatment differences (p<0.05). However, the addition of 40 ppm L-carnitine in the 200 g CP/kg diet increased (p = 0.06) thigh yields relative to BW in comparison to birds fed diets without L-carnitine, which was further confirmed via a contrast analysis (0 vs. 40 ppm L-carnitine in the 200 and 180 g CP/kg diets; p<0.05). These results indicated that dietary L-carnitine may heighten metabolism in dark meat of commercial broilers resulting in increased relative thigh tissue accretion without compromising breast accretion.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.149-154
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• 2005

Secretion of the expressed heterologous proteins can reduce the stress to the host cells and is beneficial to their recovery and purification. In this study, fed-batch cultures of Escherichia coli YK537 (pAET-8) were conducted in a 5-L fermentor for the secretory production of human epidermal growth factor (hEGF) whose expression was under the control of alkaline phosphatase promoter. The effects of feeding of glucose and complex nitrogen sources on hEGF production were investigated. When the fed-batch culture was conducted in a chemically de-fined medium, the cell density was 9.68 g/L and the secreted hEGF was 44.7 mg/L in a period of 60 h. When a complex medium was used and glucose was added in pH-stat mode, the secreted hEGF was improved to 345 mg/L. When the culture was fed with glucose at a constant specific rate of $0.25\;gg^{-1}h^{-1}$, hEGF reached 514 mg/L. The effects of adding a solution containing yeast extract and tryptone were further studied. Different rate of the nitrogen source feeding resulted in different levels of phosphate and acetic acid formation, thus affected hEGF expression. At the optimal feeding rate, hEGF production achieved 686 mg/L.