• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.171-174
• /
• 2000

The effect of the dissolved oxygen (DO) concentration on the production of manganese peroxidase by Phaenerochaete chrysosporium was studied in the immobilized reactor system. The oxygen levels significantly affected the production of manganese peroxidase (MnP) as well as that of $H_2O_2$. It is known that a high oxygen level is required to produce this enzyme. In this study, however, higher DO concentrations above a critical DO concentration inhibited MnP production. It is thought that a greater $H_2O_2$ production seen with higher DO concentrations caused adverse effects on the MnP production. On the other hand, with lower DO concentrations, $H_2O_2$ did not accumulate enough to stimulate MnP production.

• Proceedings of the Microbiological Society of Korea Conference
• /
• 2004.05a
• /
• pp.101-104
• /
• 2004

Among biological hydrogen production processes, fermentative processes have some advantages. In this research, the hydrogen producing bacterium was isolated from domestic landfill area and identified as Enterobacter sp. The strain was named Enterobacter sp. SNU-1453. Important parameters for the hydrogen process include pH, temperature, concentration of initial glucose, and kind of sugars. The pH of the culture medium significantly decreased as fermentation proceeded due to the accumulation of various organic acids, and this inhibited the $H_2$ production seriously. When pH was controlled at pH 7.0, hydrogen production was 2614.5 m1/1 in 17 hours. The increase of glucose concentration resulted in higher $H_2$ production. The productivity of this strain was 6.87 mmol $H_2/l$ per hi on concentration of 25g glucose/l. Enterobacter sp. SNU-1453 could utilize various sugars. These results indicate that Enterobacter sp. SNU-1453 has a high potential as a fermentative $H_2$ producer.

• Journal of Aquaculture
• /
• v.10 no.1
• /
• pp.69-76
• /
• 1997

Chromatium sp., densely populated on the bacterial plate of Lake Kaiike throughout the seasons, possibly fix N2 and concurrently produce H2 N2 Fixation and H2 production by Chromatium sp. were performed under photoautotrophic growth condition, and of which rates were much higher and showed expontial growth phase. Bacterial plater samples from Lake Kaiike collected on July 27, 1994 were used to know the effect of the light or H2S on N2 fixation and H2 productin by the bacteria. At low light intensity (250 lux), low rates of N2 fixation and H2 production were detected after 18 hours. However, high rates of the production were observed under the condition of high light intensity (1000 lux). On the other hand, a very low rate of N2 fixation was observed without an addition of H2S, while the bacterial rapilly increased N2 fixation and H2 production after adding H2S and the highest rate was observed in case of adding 20mg H2S-S/$m\ell$ to the bacterial plates.

• Journal of Microbiology and Biotechnology
• /
• v.22 no.2
• /
• pp.220-225
• /
• 2012

In batch culture for Poly(vinyl alcohol) (PVA)-degrading enzyme (PVAase) production by a mixed culture, higher pH (pH 7.5) was favorable for PVAase production at the prophase of cultivation, but lower pH (pH 7.0) was favorable at the anaphase. This situation was caused by the fact that the optimum pH for different key enzymes [PVA dehydrogenase (PVADH) and oxidized PVA hydrolase (OPH)] production is various. The activity and average specific production rate of PVADH reached the highest values at constant pH 7.5, whereas those of OPH appeared at pH 7.0. A two-stage pH control strategy was therefore developed and compared for its potential in improving PVAase production. By using this strategy, the maximal PVAase activity reached 2.05 U/ml, which increased by 15.2% and 24.2% over the fermentation at constant pH 7.5 and 7.0.

• Applied Chemistry for Engineering
• /
• v.29 no.2
• /
• pp.209-214
• /
• 2018

In this paper, the techno-economic analysis of glycerol steam reforming for $H_2$ production capacity of $300m^3\;h^{-1}$ was carried out. The process of glycerol steam reforming was constructed by using Aspen $HYSYS^{(R)}$, a commercial process simulator, and parametric studies for the effect of the operating temperature on $H_2$ production was performed. Moreover, the economic analysis was conducted through an itemized cost estimation, sensitivity analysis (SA) and cash flow diagram (CFD), and the unit $H_2$ production cost was 5.10 $ ${kgH_2}^{-1}$ through the itemized cost estimation of glycerol steam reforming for $H_2$ production capacity of $300m^3\;h^{-1}$. SA was employed to identify key economic factors and various economic indicators such as net present value (NPV), discounted payback period (DPBP), and present value ratio (PVR) were found according to $H_2$ selling price using CFD.

• Journal of Energy Engineering
• /
• v.15 no.2 s.46
• /
• pp.118-126
• /
• 2006

This publication provides an overview of the state-of-the-art and perspective of biological $H_2$ production from water and/or organic substances. The biological $H_2$ production processes, being explored in fundamental and applied researches, are direct and indirect biophotolysis from water, photo-fermentation, dark anaerobic fermentation and in vitro $H_2$ production. The development of biological $H_2$ production technology, as an energy carrier, started at the late 1940's in the lab-scale. Now it has a high priority in the world, especially USA, Japan, EU and Korea.

• Transactions of the Korean hydrogen and new energy society
• /
• v.19 no.1
• /
• pp.41-48
• /
• 2008

Fermentative $H_2$ production was studied using microbial consortia isolated from heat-treated ($90{\circ}C$, 20 min) sewage sludge. Important parameters investigated were carbon(C) and nitrogen(N)-sources, C/N ratio, phosphate concentration, pH and temperature during anaerobic cultivation in serum bottles. Starch, ribose, sucrose and glucose were good C-sources for the culture growth and $H_2$ production. Yeast extract was better N-source than $(NH_4)_2SO_4$ or peptone when individually added to the synthetic media, however the combination of above three N-sources exhibited the additional effect for cell growth and $H_2$ evolution. Addition of 100 mM phosphate as a buffering agent prevented the rapid pH drop during the cultivation. The optimum initial pH for the cell growth was at 7.0, whereas $H_2$ production was observed at pH 5.5. Optimum temperature for the cell growth and $H_2$ production was $37{\circ}C$. Initial C/N ratio of 1.22 in the media using glucose and yeast extract as the C- and N-sources, respectively, showed the $H_2$ yield 1.0 mol $H_2$/mol glucose.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.6
• /
• pp.1130-1135
• /
• 2008

The effect of pH on anaerobic hydrogen production was investigated under various pH conditions ranging from pH 3 to 10. When the modified Gompertz equation was applied to the statistical analysis of the experimental data, the hydrogen production potential and specific hydrogen production rate at pH 5 were 1,182 ml and 112.5 ml/g biomass-h, respectively. In this experiment, the maximum theoretical hydrogen conversion ratio was 22.56%. The Haldane equation model was used to find the optimum pH for hydrogen production and the maximum specific hydrogen production rate. The optimum pH predicted by this model is 5.5 and the maximum specific hydrogen production rate is 119.6 ml/g VSS-h. These data fit well with the experimented data($r^2=0.98$).

• KSBB Journal
• /
• v.23 no.3
• /
• pp.199-204
• /
• 2008

Culture conditions for biological hydrogen production were investigated in wastewater of Takju manufacturing factory. Rhodobacter spaeroides KCTC1425, photosynthesis bacteria, and Enterobacter cloacae YJ-1, anaerobic bacteria were used. The hydrogen production were $195.3m{\ell}{\cdot}H_2/{\ell}$ broth for Rhodobacter spaeroides KCTC1425 and $271.8m{\ell}{\cdot}H_2/{\ell}$ broth for Enterobacter cloacae YJ-1 during 36 h. The hydrogen production increased with light intensity, and were highest over 12000Lux. In mixed culture of Rhodobacter spaeroides KCTC1425 and Enterobacter cloacae Y J-1, the optimum mixing ratio of hydrogen production was 20 and 80. Adding volume of yeast extract for maximum hydrogen production was 15 $g/{\ell}$, but there was no effect over that. $Na_2MoO_4$ was most effective among the inorganic salts, and the optimum volume was 0.4 $g/{\ell}$. In semi-continuous culture, total hydrogen production was $13086m{\ell}{\cdot}H_2/{\ell}$ broth for 144 h with operating period of 24 h.

• Journal of Environmental Health Sciences
• /
• v.30 no.2
• /
• pp.149-153
• /
• 2004

The influences of pH on hydrogen production were also investigated over the pH range from 4.1 to 8.0 at HRT 10 hours. The hydrogen content for the produced gas was changed from 41 to 71% with corresponding pHs throughout this experiment. The produced hydrogen/carbon dioxide ratio was not vary significantly up to 6.0, then steepenly increased with increases in the pH. The maximal hydrogen yield was found to be 3.16 $\ell$/g sucrose at pH 5.0. Acetate production yield increased with increased pH, but butyrate production yield decreased with increased pH. Biomass yield increased with increased pH.