• Microbiology and Biotechnology Letters
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• v.45 no.1
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• pp.57-62
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• 2017

Recently, we isolated the mutant Kluyveromyces marxianus 36907-FMEL1, which demonstrated improved xylose reductase activity as compared to the parental strain, K. marxianus ATCC 36907. Effects of agitation conditions on xylitol production were verified using a bioreactor system. Under an agitation speed of 400 rpm, K. marxianus 36907-FMEL1 exhibited the highest xylitol yield (0.57 g/g) and productivity ($0.64g{\cdot}l^{-1}{\cdot}h^{-1}$) at $30^{\circ}C$. When the fermentation temperature was increased to $40^{\circ}C$, interestingly, xylitol yield and productivity were found to be increased to 21% (0.64 g/g) and 58% ($0.90g{\cdot}l^{-1}{\cdot}h^{-1}$), respectively, under the optimized agitation conditions.

• Journal of Life Science
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• v.13 no.2
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• pp.214-222
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• 2003

The microorganism isolated from soil was identified as Bacillus coagulans by morphological and biochemical analyses and API-50CH/B kit, which was an identification kit for Bacillus species, and named as B. coagulans DL-1. It produced an extracellular biopolymer. Maximum production of biopolymer was 5.00 $\pm$0.15 g/$\ell$ in a $7\ell$bioreactor with an aeration rate of 1.0 vvm and an agitation speed of 500 rpm when concentrations of glucose and yeast as the optimal carbon and nitrogen sources were 2.0% (w/v) and 0.25% (w/v), which were optimized with a flask scale. Gas chromatographic analysis showed that the biopolymer producded by B. coagulans DL-1 consisted of glucose and rhanmose and their molar ratios was about 9 : 1. Its average molecular weight was 2.80$\times$$10^5$ with gel permeation chromatographic (GPC) analysis.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.34-39
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• 2005

In order to product the furofuranoid lignans, (+)-eudesmin which is one of the secondary products from Magnolia sieboldii. through cell suspension cultures; various culture media, initial sucrose concentration, elicitations, shaking speeds, and inoculum sizes. Among the culture media tested, MS medium had a pronounced effect on suspension cell growth and (+)-eudesmin contents. The maximum dry cell weight (DCW) of 3.71 g per flask was obtained at inoculum size of 0.5 g and in MS medium supplemented with $3\%$ sucrose plus 0.5 mg/L 2,4-D after 8 weeks. (+)-Eudesmin biosynthesis was stimulated with high initial sucrose concentration ,and the maximum (+)-eudesmin production of $3.2{\mu}g/g$ DCW was achieved at 200mg/L chitosan and $5\%$ initial medium sucrose. The optimal shaking speeds for dry biomass accumulation and (+)-eudesmin contents was 130 rpm. This work is considered to be helpful for large-scale bioprocessing of Magnolia sieboldii suspension cell cultures in bioreactor.

• KSBB Journal
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• v.15 no.5
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• pp.507-513
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• 2000

The biosynthesis of lovastatin, a cholesterol lowering agent formed by the filamentous fungus Aspergillus terreus, was examined in a 2.5 L jar fermenter. In batch bioreactor cultures conducted at various agitation rates, 400 rpm showed the best result in terms of lovastatin production. Notably, the effect of pH on lovastatin biosynthesis was found to be significant: when the pH was controlled at around 5.8 during the whole fermentation period, lovastatin concentration reached 598 mg/L, which is much hihger than the amounts obtained by pH-uncontrolled and pH 7.4-controlled fermentations. In addition, both L-histidine and L-tryptophan were observed to be favorable amino acids for the enhancement of lovastatin production when 6 g/L of the respective amino acids were supplemented at the beginning of the fermentation period. By further optimization of the production media and the physical environment, lovastatin production was increased to 836 mg/L (3.5 mg/L/hr) which is approximately 10 times higher than the productivity of the basic control culture.

• Journal of Life Science
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• v.23 no.4
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• pp.542-553
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• 2013

The aim of this work was to establish the optimal conditions for the production of cellobiase by a marine bacterium, Cellulophaga lytica LBH-14, using response-surface methodology (RSM). The optimal conditions of rice bran, ammonium chloride, and the initial pH of the medium for cell growth were 100.0 g/l, 5.00 g/l, and 7.0, respectively, whereas those for the production of cellobiase were 91.1 g/l, 9.02 g/l, and 6.6, respectively. The optimal concentrations of $K_2HPO_4$, NaCl, $MgSO_4{\cdot}_{7H2}O$, and $(NH_4)_2SO_4$ for cell growth were 6.25, 0.62, 0.28, and 0.42 g/l, respectively, whereas those for the production of cellobiase were 4.46, 0.36, 0.27, and 0.73 g/l, respectively. The optimal temperatures for cell growth and for the production of cellobiase by C. lytica LBH-14 were 35 and $25^{\circ}C$, respectively. The maximal production of cellobiase in a 100 L bioreactor under optimized conditions in this study was 92.3 U/ml, which was 5.4 times higher than that before optimization. In this study, rice bran and ammonium chloride were developed as carbon and nitrogen sources for the production of cellobiase by C. lytica LBH-14. The time for the production of cellobiase by the marine bacterium with submerged fermentations was reduced from 7 to 3 days, which resulted in enhanced productivity of cellobiase and a decrease in its production cost. This study found that the optimal conditions for the production of cellobiase were different from those of CMCase by C. lytica LBH-14.

• Journal of Life Science
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• v.21 no.8
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• pp.1083-1093
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• 2011

A microorganism utilizing rice hulls as a substrate for the production of carboxymethylcellulase (CMCase) was isolated from seawater and identified as Bacillus lincheniformis by analyses of its 16S rDNA sequences. The optimal carbon and nitrogen sources for production of CMCase were found to be rice hulls and ammonium nitrate. The optimal conditions for cell growth and the production of CMCase by B. lincheniformis LBH-52 were investigated using the response surface method (RSM). The analysis of variance (ANOVA) of results from central composite design (CCD) indicated that a highly significant factor ("probe>F" less than 0.0001) for cell growth was rice hulls, whereas those for production of CMCase were rice hulls and initial pH of the medium. The optimal conditions of rice hulls, ammonium nitrate, initial pH, and temperature for cell growth extracted by Design Expert Software were 48.7 g/l, 1.8 g/l, 6.6, and 35.7$^{\circ}C$, respectively, whereas those for the production of CMCase were 43.2 g/l, 1.1 g/l, 6.8, and 35.7$^{\circ}C$. The maximal production of CMCase by B. lincheniformis LBH-52 from rice hulls under optimized conditions was 79.6 U/ml in a 7 l bioreactor. In this study, rice hulls and ammonium nitrate were developed to be substrates for the production of CMCase by a newly isolated marine microorganism, and the time for production of CMCase was reduced to 3 days using a bacterial strain with submerged fermentation.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.630-637
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• 2022

The objective of this study was to optimize industrial-grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K₂HPO₄, potassium citrate, ⳑ-cysteine phosphate, MgSO₄, and MnSO₄) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K₂HPO₄, 5.0 g/l sodium acetate, 0.1 g/l MgSO₄·7H₂O, 0.05 g/l MnSO₄·H₂O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37℃ with or without a pH control at 6.0 ± 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two-thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

• The Korean Journal of Food And Nutrition
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• v.25 no.3
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• pp.570-578
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• 2012

Compound K(ginsenoside M1) is one of saponin metabolites and has many benefits for human health. This study was to investigate Compound K produced from ginseng crude saponin extract with commercial cellulolytic complex enzyme(cellulase, ${\beta}$-glucanase, and hemicellulase) obtained from Trichoderma reesei. The effect factors(temperature, pH, ginseng crude saponin extract and enzyme concentration, and reaction time) on production of Compound K from ginseng crude saponin extract were determined by one factor at a time method. The selected major factor variables were ginseng crude saponin extract of 2%(w/v), enzyme of 7%(v/v), reaction time of 48 hr. Based on the effect factors, response surface method was proceeded to optimize the enzymatic bioconversion conditions for the desirable Compound K production under the fixed condition of pH 5.0 and $50^{\circ}C$. The optimal reaction condition from RSM was ginseng crude saponin extract of 2.38%, enzyme of 6.06%, and reaction time of 64.04 hr. The expected concentration of Compound K produced from that reaction was 840.77 mg/100 g. Production of Compound K was 1,017.93 mg/100 g and 862.31 mg/100 g, by flask and bench-scale bioreactor($2.5{\ell}$) system, respectively.

• KSBB Journal
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• v.17 no.1
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• pp.73-79
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• 2002

The method to optimize the microbial production of ethanol from CO using Clostridium ljungdahlii was developed. The kinetic parameter study on CO conversion with Clostridium ljungdahlii was carried out and maximum CO conversion rate of 37.14 mmol/L-hr-O.D. and $K_{m}$ / of 0.9516 atm were obtained. It was observed that method of two stage fermentation, which consists of cell growth stage and ethanol production stage, was effective to produce ethanol. When pH was shifted from 5.5 to 4.5 and ammonium solution was supplied to culture media as nitrogen source at ethanol production stage, the concentration of ethanol produced was increased 20 times higher than that without shift. Ethanol production from CO in a fermenter with Clostridium ljungdahlii was optimized and the concentration of ethanol produced was 45 g/L and maximun ethanol productivity was 0.75 g ethanol/L-hr.