• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.581-584
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• 2019

In this study, the carbon monoxide (CO)-fermenting acetogen, Clostridium sp. AWRP was subjected to chemical mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine (NTG) to generate a CO-resistant mutant. Among the 26 colonies obtained, the highest alcohol production was observed in one isolate, named C1. Compared to the wild-type strain, the C1 strain exhibited 1.5- and 3.4-fold higher CO consumption rate and alcohol selectivity, respectively. The total CO consumption of strain C1 could be further enhanced by increasing the content of metal ions, such as nickel and iron. The highest ethanol titer (5.7 g/l) was achieved by 5-fold increase in the iron concentration.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.447-452
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• 2011

Depletion of petroleum increased the need of alternative energy and chemical resources. Biomass, a renewable resource, can be transformed to bioenergy and biomaterials, and the materials from biomass will ultimately substitute petroleum based energy and chemical compounds. In this perspective, production of C4-C6 compounds for bioenergy and biomaterials are described for understating of current research progress. n-Butanol and n-butyric acid, the major C4 compounds, are produced by Clostridium tyrobutyricum, Clostridium beijerinckii, and Clostridium acetobutylicum. n-Hexanoic acid, a typical C6 compound, is produced by Clostridium kluyveri and Megasphaera elsdenii. Reported maximum amount of n-butanol, n-butyric acid and n-hexanoic acid was 21, 55, and 19 g/L, respectively, and extraction of these C4-C6 compounds are induced increase production by those anaerobic bacteria. In addition, a new bacterium Clostridium sp. BS-1 produced 5 g/L of n-hexanoic acid using galactitol.

• Korean Journal of Microbiology
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• v.34 no.3
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• pp.91-95
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• 1998

Cellulase producing microorganisms, GPC-1, GPC-2, GNR-1 GNR-2, and GNR-3, were screened from the Rumen fluid of Korean Native Cattle. Isolated GPC-1 and GPC-2 were identified as Ruminococcus sp. according to results of the Gram stain and anaerobic characteristics. Based on morphological and physicochemical identification, the isolate GPC-1 and GPC-2 were identified as strains of Ruminococcus albus and Ruminococcus flavefaciens, respectively. Isolated GNR-1 GNR-2 and GNR-3 were identified as Bacteroides sp., Butyrivibrio sp. and Clostridium sp. according to results of the Gram stain, $H_2S$ producition and spore formation, respectively. Based on morphological and physicochemical identification, the isolate GNR-1 GNR-2 and GNR-3 were identified as strains of Bacteroides succinogenes, Butyrivibrio fibrisolvens and Clostridium cellobioparum, respectively.

• Microbiology and Biotechnology Letters
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• v.21 no.1
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• pp.41-46
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• 1993

A strain showing antibiotic activities against various bacteria and fungi was selected from approximately 2,000 microorganisms obtained from soil samples. This strain, designated as KH-431, was identified as a Clostridium sp. by its morphological, physiological and biochemical characteristics. The highest production of the antibiotics was achieved in a fermentation medium containing sorbitol, yeast extract, d-biotin and $CaCl_2$ The antibiotics were isolated from the culture broth by solvent extraction using ethyl acetate, silica gel column chromatography and recrystallization. Two kinds of antibiotics, KG-431A and KG-431B were obtained after the purification procedure, and only KG-431B was successful to recrystallize.

• 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.

• Korean Journal of Microbiology
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• v.48 no.4
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• pp.254-261
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• 2012

The purpose of this research was to optimize electric current production of sediment microbial fuel cells by injecting glucose and to investigate its impact on microbial communities involved. It was shown that injection of proper concentration of glucose could increase electric current generated from sediment microbial fuel cells. When 1,000 mg/L of glucose, as opposed to higher concentrations, was injected, electric current increased up to 3 times. This increase is mainly attributed to the mutual relationship between fermenting bacteria and exoelectrogenic bacteria. Here the organic acids generated by fermenting bacteria could be utilized by exoelectrogenic bacteria, removing feedback inhibition caused by the organic acids. When glucose was injected, the population of Clostridium increased as to ferment injected glucose. Glucose fermentation can have either a positive or negative effect on electric current generation. When exoelectrogenic bacteria may readily utilize the end-product, electric current could increase. However, when the end-product was not readily removed, then detrimental chemical reactions (pH decrease, methane generation, organic acids accumulation) occurred: exoelctrogenic bacteria population declined and non-microbial fuel cell related microorganisms prospered. By injecting a proper concentration of glucose, a mutual relationship between fermenting bacteria, such as Clostridium, and exoelectrogenic bacteria, such as Geobacter, should be fulfilled in order to increase electricity production in mixed cultures of microorganisms collected from the aquatic sediments.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.2
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• pp.97-103
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• 2017

In this study, variations of hydrogen production were investigated with food waste fermentation in the presence of heavy metals. Hydrogen production was 79.48 mL/g COD with fermentation of food waste. In the presence of 1 mg/L of zinc, the hydrogen production was decreased about 60%. When the copper is present, the production of hydrogen is severely inhibited, while the coexistence of copper with zinc relaxes the inhibition of copper and restores hydrogen production. Butyric acid or acetic acid was observed as the main species during hydrogen production. Klebsiella sp., Clostridium sp., and Dysgonomonas sp. were mainly appeared in the samples not containing heavy metals. However, Enterococcus sp. extremely influenced the hydrogen production activities of samples containing zinc or copper.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.184.1-184
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• 2005

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.3
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• pp.41-51
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• 2012

Biohydrogen production and analysis of microbial community were attempted from the sugar manufacturing wastewater with anaerobic fermentation process. Addtion of nutrients ($N{\cdot}P$) into sugar manufacturing wastewater stimulates hydrogen production from 9.53 to $26.67m{\ell}$ $H_2/g$ COD. Butyric acid, acetic acid, lactic acid, and propionic acid were detected in the sample of the anaerobic fermentation process. Butyric acid/Acetic acid(B/A) ratio was increased 0.50 to 0.92 according to the nutrients addtion into the wastewater. Microbial community was analyzed as Clostridium sp. in the phylum of Firmicutes and Klebsiella sp., Erwinia sp., and enterobacter sp. of the class of $\gamma$-Proteobacteria. As the improvement of hydrogen production, Erwinia sp. was decreased and Klebsiella sp. was increased.

• Current Research on Agriculture and Life Sciences
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• v.20
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• pp.49-54
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• 2002

This study was conducted to investigate physicochemical and microbiological properties on waste composts of mushroom. The waste compost of mushroom consisted of 43.29% organic matter(O.M.), 27.0 O.M./Nitrogen, 1.60% total nitrogen, 46.48% water content, 0.64% salt content, 1.32% $P_2O_5$ 1.18% $K_2O$ and dry base. The microorganisms in the waste compost of mushroom were counted $1.6{\times}10^{10}cfu/g$. The main population of aerobic bacteria were Bacillus lentimobus, B. coagulans, B. brevis, Clostridium thermocellum, Escherichia coli, Streptomyces thermovulgaris, S. thermofuscus, Micropolyspora faeni, Aspergillus sp. and Penicillum sp..