• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.1
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• pp.81-88
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• 2010

Characteristic of hydrogen production was investigated to find the optimum heat pretreatment conditions for the anaerobic fermentation of food waste. The heat pretreatment of food waste enhanced the hydrogen yield due to the increase of soluble chemical oxygen demand (SCOD) and carbohydrate content. This result revealed that the maximum degrees of disintegration of SCOD and carbohydrate content were 55.1% and 223.6%, respectively. On the other hand, the improvement of hydrogen yield was insignificantly affected by heating reaction time at longer than 20 min; the increase of hydrogen yield was only about 7% between 20min and 1 hour. Therefore, the increase of reaction time more than 20min was not necessary.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.2
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• pp.142-150
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• 2009

This paper presents bio-ethanol production from fruit wastes as it possibly alternate fossil fuel in the future. To illustrate the component ratio in exocarps of fruit wastes such as pears, apples, and persimmons, the amount of moisture, lignin, $\alpha$, $\beta$, $\gamma$-cellulose, and ash content were respectively examined by the ingredient analysis. Also, the amount of the glucose obtained from the enzyme hydrolysis using the axocarps was investigated. It was found in our results that the energy efficient process requires different temperature conditions for the saccharification step($50^{\circ}C$ and the fermentation step($30^{\circ}C$ in ethanol synthesis.

• 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.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.6-11
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• 1990

Hydrogen evolution from biomass-derived carbohydrates by some Clostridia and optimal culture conditions for hydrogen evolution were investigated. Among the organisms tested, Clostridium butyricum was efficient hydrogen producer with starch, xylan, pectin, cellobiose and xylose. In batch fermentation of Cl. butyricum, optimal conditions for hydrogen evolution were achieved at pH 7.0-8.5, 10-50 mM phosphate, and 2% (w/v) glucose. Total amount of molecular hydrogen evolved by the organism slightly increased at the presence of acetate (<150 mM) or butyrate (<20 mM) in the initial fermentation medium. Especially, in case of more than the above concentration of butyrate, growth and hydrogen evolution were dramatically inhibited. In the conditions were described here, 70 mmole of molecular hydrogen per mg of DCW was produced with 1%(w/v) glucose by the organism.

• KSBB Journal
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• v.20 no.6
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• pp.401-407
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• 2005

Optimum culture conditions and medium composition for hydrogen production by Clostridium beijerinckii KCTC 1785 were investigated. Initial pH and temperature for growth were 7.0 and $35^{\circ}C$, respectively. Agitation accelerated the hydrogen production. Although C. beijerinckii KCTC 1785 could grow up to 6%(w/v) glucose in the medium, the optimum glucose concentration for hydrogen production was 4% and hydrogen content in the biogas was 37%(v/v). However, the economical glucose concentration for hydrogen production was 1% regarding to the residual glucose which was not used in the medium. During hydrogen fermentation, acetic and butyric acid were produced simultaneously. High concentrations of acetic(>5,000 mg/L) or butyric(>3,000 mg/L) acid inhibited hydrogen production. When pH was maintained at 5.5 in the batch fermentation, 1,728 mL of hydrogen was produced from 0.5% glucose within 15 hr. $H_2$ yield was estimated to be 1.23 mol $H_2/mol$ glucose. It was found that yeast extract or tryptose in the medium was essential for hydrogen production.

• Natural Product Sciences
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• v.17 no.1
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• pp.58-63
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• 2011

Insampaedok-san is a traditional medicine used for the treatment of colds. We investigated several compounds in Insampeadok-san, and tested their neuroprotective and anti-oxidative activities after fermentation with Lactobacillus. The amounts of four marker compounds (ferulic acid, hesperidin, 6-gingerol and glycyrrhizin) and unidentified compounds in Insampaedok-san (IS) and fermented Insampaedok-san (FIS) were measured and compared by an established HPLC-DAD method. Neuroprotective activity of IS and FIS extracts was evaluated and compared after glutamate-induced neurotoxicity in HT22 cells. Anti-oxidative activity of IS and FIS was also compared in DPPH free radical, hydroxyl radical and hydrogen peroxide scavenging activity assays. Contents of two compounds, ferulic acid and glycyrrhizin were decreased while 6-gingerol was increased by fermentation. FIS showed more potent neuroprotective activity than IS. DPPH, hydroxyl radical and hydrogen peroxide scavenging was slightly increased by FIS when compared to IS. In conclusion, fermentation with Lactobacillus can vary the amounts of the marker compounds in IS and improve neuroprotective and anti-oxidative activities of IS.

• KSBB Journal
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• v.18 no.2
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• pp.149-154
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• 2003

The hydrogen-producing bacterium was isolated from fresh water and identified as Enterobacter cloacae. The isolated was named Enterobacter cloacae YJ-1. In batch culture, The optimum cultivation temperature and pH of strain YJ-1 was 35℃ and 7.5, respectively. All of the added glucose was consumed completely during fermentation even though pH was not controlled. Amount of hydrogen produced on each condition of 2% glucose, 4% sucrose and 5% fructose was 950, 1000 and 948 mL/L, respectively and resulted in increasing hydrogen production approximately 2.5-times more than controlled condition. The maximum hydrogen production was obtained when 50 mM phosphate was added. In repeated-batch culture, hydrogen gas of 1920 mL/L was totally produced for 48. The maximum hydrogen was produced on the condition of 0.5% yeast extract, but the production amount was not changed on the condition of over 0.5%. Most of the organic acids produced during the fermentation were formic and acetic acid, and propionic acid was moiety also generated.

• Journal of the Korea Organic Resources Recycling Association
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• v.19 no.1
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• pp.102-108
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• 2011

Characteristics of hydrogen production from various food wastes in anaerobic batch reactors were evaluated to assess the energy potential of organic wastes. Organic wastes which were used in this study were scallion as vegetable, apple as fruit, rice as grain and pork as meat. Ultimate hydrogen yield of scallion, apple, rice and pork were 0.46, 0.47, 0.62 and $0.05mol\;H_2/mol\;hexose$, respectively. On the other hand, hydrogen production rates of scallion, apple, rice and pork were 0.013, 0.021, 0.014 and $0.005mol\;H_2/mol\;hexose/h$, respectively. These results indicated that anaerobic hydrogen fermentation from food waste except for meat was effective in removing organic material as well as producing renewable energy. Volatile fatty acids increased as hydraulic retention time was increased. In the hydrogen fermentation, acidification degree of rice was measured as the highest rate of 75.8% whereas pork was found as the lowest rate of 35.2%.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.672-678
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• 2014

In this study, variations of fermentative hydrogen production and microbial community were investigated with different nitrogen concentration of food waste. Optimum hydrogen production rate was acquired at 200 mg/L nitrogen concentration of the food waste. Which was eqivalent to 83.43 mL/g dry biomass/hr. However, bio-hydrogen production was inhibitedly reduced at over 600 mg/L of nitrogen concentration whereas proportional relation between hydrogen production and B/A ratio were not observed. Most dominant specie of the microbial community analyzed was Clostridium sp. throughout PCR-DGGE analysis of 16S rDNA. It revealed that most contributing microorganism producing hydrogen were Enterococcus faecium partial, Klebsiella pneumoniae strain ND6, Enterobacter sp. NCCP-231, and Clostridium algidicarnis strain E107 in this experiment.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.465-469
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• 2006

Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and tested for hydrogen production via anaerobic fermentation of sucrose. Each reactor consisted of a column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed with changing flow rate into the capped reactor, hydraulic retention time and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% for all conditions tested. Hydrogen production rates increased up to $10.5 L{\cdot};h^{-1}{\cdot}L^{-1}$ of reactor when influent sucrose concentrations and recycle rates were varied. Hydrophobic media provided higher value of hydrogen production rate than hydrophilic media at the same operation conditions. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate and butyrate. The reactor filled with hydrophilic media became clogged with biomass and bio gas, requiring manual cleaning of the system, while no clogging occurred in the reactor with hydrophobic media. In order to make long-term operation of the reactor filled with hydrophilic media feasible, biofilm accumulation inside the media in the reactor with hydrophilic media and biogas produced from the reactor will need to be controlled through some process such as periodical backwashing or gas-purging. These tests using trickling bed biofilter with hydrophobic media demonstrate the feasibility of the process to produce hydrogen gas in a trickle-bed type of reactor. A likely application of this reactor technology could be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.