• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.309-316
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• 2004

Chlamydomonas reinhardtii UTEX 90 was cultivated with continuous supply of 2% $CO_2$ using TAP media at $25^\circ{C}$ and produced biomass 1.18 g of dry cell weight/L for 4 days. C. reinhardtii algal biomass(CAB) was concentrated to 20 times by volume and converted into hydrogen and organic acids by anaerobic fermentation using Clostridium butyricum. Organic acids in the fermentate of CAB were consecutively used to produce hydrogen by Rhodobacter sphaeroides KD 131 under the light condition. Approximately 52% of starch in the concentrated CAB which had 4-5.8, 24-26 and 6-7 g/L of starch, protein and fat, respectively was degraded by Cl. butyricum at $37^\circ{C}$. During this process, hydrogen and some organic acids, such as formate, acetate, propionate, and butyrate, respectively were produced. Further conversion of the organic acids in anaerobic fermentate of CAB by Rb. sphaeroides KD131 produced hydrogen from the anaerobic fermentate under the illumination of 8 klux using halogen lamp at $30^\circ{C}$. The result showed that hydrogen was evolved by the anaerobic conversion using Cl. butyricum and then by the photosynthetic fermentation using Rb. sphaeroides KD131. It indicated that the two-step conversion process produced the maximum amount of hydrogen from algal biomass which contained carbohydrate, protein, and fat via organic acids.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.10-16
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• 2013

Characteristics of biological hydrogen production rate and organic acid under anaerobic fermentation process were investigated with sugar wastewater. Hydrogen production rate was higher with alkaline pre-treatment than acidic pre-treatment, resulting in 70% increment. An adequate supply of the nutrients (N or P) into raw sugar wastewater could increase hydrogen production rate. Carbohydrate degradation of the anaerobic fermentation process was not directly related with hydrogen production. Sugar wastewater with the addition of the nutrients shows 3 times higher B/A ratio than the raw sugar wastewater. B/A ratio of the wastewater with alkaline pre-treatment and nutrients addition was most higher than other samples, showing 4.02 of B/A ratio. Higher B/A ratio shows higher hydrogen production rate at each sample.

• New & Renewable Energy
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• v.5 no.4
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• pp.80-85
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• 2009

The effects of various organic wastes on anaerobic fermentative hydrogen production were studied using enriched mixed microflora in batch tests. Rotten fruit, corn powder and organic wastewater enriched with sulfate (up to 1,000 mg/L) were used for experiments. Maximum hydrogen production (547.1 mL) was observed from rotten apple with initial substrate concentration of 132.2 g COD/L. The experimental result on sulfate enriched organic wastewater indicated that hydrogen production is not adversely influenced by relatively high sulfate concentration. Residual sulfate content remained at 96-98 % after 75 hours of reaction, which showed that no major sulfate reduction was occurred at pH 5.3-5.5 in the reactor. The volatile fatty acid (VFA) fractions produced during the reaction was in the order of butyrate > acetate > propionate in all experiments. The results of this study would be useful for controlling the conditions on fermentative hydrogen production using different feedstocks.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.2
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• pp.49-54
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• 2011

This study was conducted to evaluate the performance of methane fermentation from effluent of hydrogen fermentation reactor in anaerobic baffled reactor (ABR) and anaerobic sequencing batch reactor (ASBR). Two reactors were operated at organic loading rate of $1.0kg\;COD/m^3{\cdot}d$ and hydraulic retention time (HRT) of 20 day. Methane production rates of ABR and ASBR for start-up periods were 0.04 L/L/d and 0.19 L/L/d, respectively, whereas maximum methane production rates of ABR and ASBR were 0.25 L/L/d and 0.31 L/L/d, respectively. Removal rates of chemical oxygen demand (COD) in ABR and ASBR for start-up periods were 89% and 92%, respectively. After startup periods, removal rates of COD and volatile solids (VS) in ABR and ASBR were maintained over 90%. The specific methanogenic activity (SMA) increased as microorganism acclimated to the substrate.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.394-398
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• 2005

This study aimed to develop a novel anaerobic two-stage process converting food waste to $H_2$ and $CH_2$. The anaerobic two-stage process was devised by combining hydrogen fermentation with methane fermentation. At the high loading rate of 12.3 kg $Vs/m^3/d$, it could remove 72.5%of VS and convert $VS_{removed}$ to $H_2$ (28.2%) and $CH_4$ (69.9%) on COD basis in 8 days.

• Korean Chemical Engineering Research
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• v.44 no.1
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• pp.16-22
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• 2006

Biological hydrogen production processes are more environment-friendly and less energy intensive than thermochemical and electrochemical processes. The biological process can be divided into two categories: photosynthetic hydrogen production and hydrogen production by dark fermentation. Photosynthetic process produces hydrogen mainly from water and reduces $CO_2$ simultaneously. Dark fermentation is a dark and anaerobic process that produces hydrogen by fermentative bacteria from organic carbon. The article presents a survey of biological hydrogen production processes.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.5
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• pp.641-647
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• 2007

This study aims to find out optimum condition for hydrogen production and organic removal when treating food and swine wastewater together. For this purpose, various batch tests were conducted by changing mixture ratio from 6:4 (food wastewater:swine wastewater) to 1:9 without pretreatment process. For hydrogen production through anaerobic fermentation, the mixture ratios of R-1 (6:4), R-2 (5:5) and R-6 (1:9) were out of pH range appropriate for hydrogen production and mixture ratios of R-3 (4:6), R-4 (3:7), and R-5(2:8) showed appropriate hydrogen production where their pH ranges were 5.1~5.5. Especially in case of R-3, it consistently maintained appropriate pH range for hydrogen production for 72hr and produced maximum hydrogen. The characteristics of hydrogen production and cumulative hydrogen production according to each mixture ratio showed that R-1, R-2 and R-6 did not produce any hydrogen, and maximum hydrogen productions of R-3, R-4 and R-5 were 593ml, 419ml and 90ml, respectively. Total cumulative hydrogen productions of R-3, R-4 and R-5 were 1690ml, 425ml and 96ml, respectively. Based on previous results, it was concluded that, the most appropriate mixture ratio of food wastewater and swine wastewate rwas 4:6 (R-3). The experiment for COD removal rate to evaluate organic removal efficiency revealed that R-3, R-4 and R-5 showed high removal efficiencies during the highest hydrogen production amount and the highest efficiency was 41% with R-3.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.510-516
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• 2016

This study examines the effects of linear alkylbenzene sulfonate on hydrogen fermentation of food waste. The hydrogen production rate was similar with different linear alkylbenzen sulfonate (LAS) concentrations. The maximum hydrogen yield increased with increasing LAS concentration. The highest maximum hydrogen yield was $0.550{\pm}0.005mol$ H2/mol hexose at LAS for 5.52 mg/L. But the maximum hydrogen yield decreased above LAS for 11.05 mg/L. The concentration of acetate in control reactor was increased, but it decreased with increasing LAS concentration in other reactors.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.1
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• pp.131-138
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• 2006

In this study, the optimum condition of pH was investigated on the hydrogen gas production under anaerobic fermentation process. The results of the experiment showed that the optimum condition was observed at pH 6, resulting in 1175.87 mL/L of hydrogen gas production rate and 22.51% theoretical hydrogen conversion ratio. Hydrogen gas production rate and theoretical hydrogen conversion ratio were 901.77 mL/L and 17.48 % respectively at pH 5. At pH 7 and 8, the production rate of hydrogen gas was little low as 82.15 mL/L. Among the organic acids from the sucrose fermentation, propionate was observed as the dominant acid at pH 7 and 8 but butyrate was the dominant at pH 5 and 6.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.144-154
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• 2008

The rumen microbial ecosystem produces methane as a result of anaerobic fermentation. Methanogenesis in the rumen is thought to represent a 2-12% loss of energy intake and is estimated to be about 15% of total atmospheric methane emissions. While methanogenesis in the rumen is conducted by methanogens, PCR-based techniques have recently detected many uncultured methanogens which have a broader phylogenetic range than cultured strains isolated from the rumen. Strategies for reduction of methane emissions from the rumen have been proposed. These include 1) control of components in feed, 2) application of feed additives and 3) biological control of rumen fermentation. In any case, although it could be possible that repression of hydrogen-producing reactions leads to abatement of methane production, repression of hydrogen-producing reactions means repression of the activity of rumen fermentation and leads to restrained digestibility of carbohydrates and suppression of microbial growth. Thus, in order to reduce the flow of hydrogen into methane production, hydrogen should be diverted into propionate production via lactate or fumarate.