• KSBB Journal
• /
• v.10 no.2
• /
• pp.159-165
• /
• 1995

Methyl fructoside was continuously produced in suspended bed enzyme reactor using alginate-enclosed microspheres biocatalyst which was developed for enzymatic synthesis of methyl fructoside. And the continuous operating conditions were optimized with reactor simulation in order to demonstrate a feasibility of commercialization of the continuous enzymatic production process development. The yield and productivity of methyl fructoside were as high as 47.1%o and $2g/\ell$-hr, respectively. The optimum operating conditions were pH 4.8, 30%(v/v) of methanol content and $2U/m\ell$ of enzyme activity when the initial concentration of sucrose is $0.291mo1/\ell$ at the reaction temperature of $25^{\circ}C$.

• KSBB Journal
• /
• v.20 no.6
• /
• pp.443-446
• /
• 2005

Hydrogen fermentation from food waste was attempted at different hydraulic retention time(HRT, 18-42 h). A continuous reactor fed with ground, alkali-treated and diluted food waste(average VS 4.4%) exhibited stable hydrogen production during 126 days. Hydrogen production depended on HRT, resulting in the maximum values of 25.8 mL $H_2/g\;VS_{added}$, 0.36 mol $H_2/mol\;hexose_{added}$ and 0.91 L $H_2/L/d$ at HRT 30 h. n-Butyrate and isopropanol production increased with hydrogen production increased, while acetate production decreased. The fermentation efficiency ranged from 53.3 to 65.7%, which implied that hydrogen fermentation would substitute conventional acidogenesis of food waste.

• Journal of Environmental Health Sciences
• /
• v.29 no.3
• /
• pp.72-78
• /
• 2003

In the process of producing chitosan from crustacean shell, the use of excessive acid and alkli is causing the problems of environmental pollution and of production cost. In this study, one way to solve these problems is to cultivate fungi, then, to extract chitosan from the cell wall. By means of flask incubation and batch cultivation, the optimum cultivation conditions for mass production of continuous cultivation was found. Four strains used for the production of fungal chitosan were Gongronella butleri IF08080, Absidia coerulea IF05301, Rhizopus delemar IF04775, Mucor tuberculisporus IF09256. In flask incubation to select strain of producing much chitosan by means of experiment of the effect of initial pH, Absidia coerulea IFO 5301 had highest yield in FCs, 258.1 $\pm$ 47.3 mg/200 $m\ell$l at pH 6.5. In flask incubation under the optimum cultivation condition, temperature 27$^{\circ}C$, culture time 6days, glucose 2%, peptone 1%, (NH$_4$)$_2$ SO$_4$ 0.5%, $K_2$HPO$_4$ 0.1 %, Nacl 0.1 %, MgSO$_4$ㆍ7$H_2O$ 0.05%, CaCl$_2$ㆍ2$H_2O$ 0.01 %, the yield of DCW brought the highest yields. In batch bioreactor, the optimum cultivation condition was that cell suspended solution was 70 $m\ell$, aeration rate 0.5 l/min, agitation rate 800 rpm, culture time 36 hr. In continuous bioreactor, the optimum substrate flow rate was 4 ι/day.

• Microbiology and Biotechnology Letters
• /
• v.27 no.1
• /
• pp.46-53
• /
• 1999

The purpose of this study was to optimize the conditions of continuous mixed culture of C.butyricum and R. spaeroides K-7, which were able to produce hydrogen using biomass-dreived substrate. To investigate the possibility of continuous culture, semi-continuous culture was carried out for 20 days. In semi-continuous culture using the reactor system, the replacement rate of fresh medium was 30% of total medium volume for the highest hydrogen evolution. In continuous culture, the optimum dilution rate was determined to be 0.05$h^{-1}$. The continuous culture produced 3.1 times as compared with the hydrogen on batch culture. On the other hand, the continuous mixed culture produced 1.3~2.1 times as much as hydrogen of the continuous monoculture of C. butyricum. When 10g of glucose in the media (1l) was supplied as a carbon source on continuous culture, mixed culture of C. butyricum and R. sphaeroides K-7 increased hydrogen evolution rate. Because considerable amount of glutamate was contained in waste water of glutamate fermentation, utilization of glutamate was examined in mixed culture. As a result of examination, production of hydorgen was slightly inhibited by high concentration of glutamate, more than 20mM, on continuous monoculture of R. sphaeroides K-7. On the other hand, both on continuous monoculture of C. butyricum and on mixed culture of C. butyricum and R. sphaeroides K-7, production of hydrogen was not inhibited by high concentration of glutamate such as 100mM. Hence this suggests that high concentration of waste water can be used as good substrate for hydrogen production on monoculture of C. butyricum and mixed culture of C. butyricum and R. sphaeroides K-7.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.11
• /
• pp.1369-1373
• /
• 2009

Succinic acid was produced by continuous fermentation of Actinobacillus succinogenes sp. 130Z in an external membrane cell recycle reactor to improve viable cell concentration and productivity. Using this system, cell concentration increased to 16.4 g/l at the dilution rate $0.2\;h^{-1}$, up to 3 times higher than that of batch culture, and the volumetric productivity of succinic acid increased up to 6.63 g/l/h at the dilution rate $0.5\;h^{-1}$, 5 times higher than that of batch fermentation. However, in the continuous culture using a high dilution rate, operational problems including severe membrane fouling and contamination by lactic acid producer were observed. Another succinic acid producer, Mannheimia succiniciproducens MBEL55E, was also utilized in this system, and the cell concentration and productivity of succinic acid at the dilution rate of $0.3\;h^{-1}$ were found to be above 3 and 2.3 times higher, respectively, compared with those obtained at the dilution rate of $0.1\;h^{-1}$. These observations give a deep insight into the process design for a continuous succinic acid production by microorganisms.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.3
• /
• pp.559-561
• /
• 1992

Three strains each of L. bulgaricus and S. thermophilus isolated from indigenous dahi were examined for their rate of acid production and corresponding pH values in skim milk medium incubated at $40^{\circ}C$. No significant increase in titrable acidity or decrease in pH were recorded from initial period up to 2nd hour in both the strains. Following this period, however, there was a continuous increase in titrable acidity and a decrease in pH value in the milk for all the tested strains. Further it was observed that there was a variation among these strains for their acid production rate. High rate of acid production was recorded for the L. bulgaricus as compared to S. thermophilus. The results further, suggested that efforts should be made to select a proper pair of L. bulgaricus and S. thermophilus according to their rate of acid production, at a particular temperature in order to produce a good quality product.

• Korean journal of applied entomology
• /
• v.4
• /
• pp.19-24
• /
• 1965

In an attempt to find a satisfactory environmental factors which facilitate abundant conidial production of Piriculariaoryzae Cav. on tomato juice media, various environmental factors were studied for their effect on sporulation and mycelial growth of the fungus. Those factors were conditions of irradiation, color of light, age of culture and pH of the media. l) Continuous exposure to fluorescent light (Mitsubish FL-20-35 W) produced more conidia and much mycelial growth than did intermittent photoperiods and darkness. 2) Of 3 cellophane filters and direct exposure to fluorescent light used, conidia were produced best under the direct exposure to the light. Conidial production in color filter conditions sequently decreased with red, yellow and blue. Growth of mycelium was not significantly different within colors. 3) Periodic irradiation of 12-hour unit brought about zones on mycelial growth no matter what the color filter was used. 4) Older cultures responding to the light were more stimulated by light than were the younger one in the conidia production, but maximum production of conidia was 48 hours of age in this case. 5) Color of the mycelial mat and the aerial mycelium seemed to have a close relation to the production of conidia. The more darkness of the mycelial mat was produced the more conidia and the much aerial mycelium was produced the least conidia. The color of mycelium was more dark under the continuous irradiation than continuous darkness, while the periodic irradiation showed intermediate effect. 6) The concentration of hydrogen ion for growth and sporulation of the fungus was investigated the ranges between 5 and 9. The best pH for the fungus was also noted at 7. whereas the below of pH 4 was not occurred any mycelial growth and sporulation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.2 no.3
• /
• pp.477-480
• /
• 1989

• Journal of Electrochemical Science and Technology
• /
• v.12 no.4
• /
• pp.406-414
• /
• 2021

Electrochemical devices are constructed for continuous syngas (CO + H₂) production with controlled selectivity between CO₂ and proton reduction reactions. The ratio of CO to H₂, or the faradaic efficiency toward CO generation, was mechanically manipulated by adjusting the space volume between the cathode and the polymer gas separator in the device. In particular, the area added between the cathode and the ion-conducting polymer using 0.5 M KHCO₃ catholyte regulated the solution acidity and proton reduction kinetics in the flow cell. The faradaic efficiency of CO production was controlled as a function of the distance between the polymer separator and cathode in addition to that manipulated by the electrode potential. Further, the electrochemical CO₂ reduction device using Au NPs presented a stable operation for more than 23 h at different H₂:CO production levels, demonstrating the functional stability of the flow cell utilizing the mechanical variable as an important operational factor.

• KSBB Journal
• /
• v.16 no.5
• /
• pp.474-479
• /
• 2001

Fed-batch culture, single stage and two stage continuous cultures of Corynebacterium glutamicum SH 35 for the production of $_{L}$-Iysine were performed and compared. In the case of fed batch culture, $_{L}$-Iysine concentration, $_{L}$-Iysine yield and $_{L}$-Iysine productivity was 129.2 g/L, 47.0% and 3.08 g/L/h, respectively. In a single-stage continuous culture, optimum dilution rate and pH was 0.1 h$^{-1}$ and 6.9, respectively, and optimum concentration of sugar and ammonium sulfate in a medium reservoir was 108 g/L and 25 g/L, respectively. Under the optimized conditions, 67 of cell concentration($OD_{610}$), 44.2 g/L of lysine concentration, 41% of $_{L}$-Iysine yield and 4.39 g$L^{-1}$ of $_{L}$-Iysine productivity were obtained. In a two-stage continuous culture, optimum dilution rate was 0.075 $h^{-1}$. Under the conditions, 103 of cell concentration($OD_{610}$) 84.0g/L of $_{L}$-Iysine concentration and 46% of $_{L}$-Iysine yield were obtained.