• Journal of the Korea Organic Resources Recycling Association
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• v.4 no.1
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• pp.1-11
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• 1996

The effect of seeding on the thermophilic composting of food waste was investigated with selected strains of yeast, thermophilic bacteria and the mixed strains of yeast and bacteria in the lab-scale composter at $50^{\circ}C$. The results demonstrated that in all case the growth of yeasts preceded the growth of thermophilic bacteria by one or two days. The seeding of bacteria alone was ineffective for thermophilic bacterial development and the rapid increase of total thermophilic bacterial count was obtained by mixed seeding of yeasts and bacteria. Moreover, the bacterial growth was accelerated by the addition of yeasts alone. It was revealed that the yeasts removed organic acids from the food waste at the initial period and consequently induced the growth of thermophilic bacteria. The results presented in this paper indicate the indispensable role of yeasts for thermophilic process of food waste composting.

• Food Science and Preservation
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• v.10 no.1
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• pp.70-74
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• 2003

The distribution of mesophilic and thermophilic bacteria in milled rice was not different according to growing land and variety of rice. However, The number of these bacteria were abundant in milled rice of lower milling degree or longer storage period. The growth of thermophilic bacteria in cooked rice of electric rice cooker was rapidly increased during storage of lower temperature below 75 $^{\circ}C$. Thermophilic bacteria were not appeared just after cooking. After cooked rice was stored far 18∼24 hon thermophilic bacterial growth was rapidly increased by changing spore to vegetative cell. The positive relation between cell number of thermophilic bacteria and occurrence of off-odor was slightly observed. The number of thermophilic bacteria in upper cooked rice of oven and was higher than those in inner and lower cooked rice. Major volatile compound of milled rice cooked and stored in electric rice cooker was hexanal oriented from rice. After long storage, it was confirmed that furan was major volatile compound as off-odor.

• Microbiology and Biotechnology Letters
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• v.25 no.6
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• pp.623-629
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• 1997

The studies of isolation and physiological characteristics of mesophilic or thermophilic bacteria from thermophilic oxic process (TOP) treating Chinese restaurant wastes were conducted. Chinese restaurant wastes were consist of moisture; 75.8%, solids; 24.2% and ash; 0.49%. The volatile solid was about 99% of total dry solids. In wastes used in this experiment, there was content of crude protein; 4.47%, crude lipid; 3.56%, free sugar, 0.4% , crude starch; 10.34% and crude fiber 3.14%, respectively. And then it has about 4,970 kcal/kg-dry solid of Chinese restaurant wastes. From TOP treating the chinese restaurant wastes, 37 strains of mesophilic or thermophilic bacteria were primarily isolated using medium used for the isolation and among them 6 strains of thermophilic and 7 strains of mesophilic bacteria were selected by testing the activities of amylase, cellulase, protease and lipase. TB-1, TB-9 as thermophilic bacteria and MB-15-1, 15-2, MB23 as mesophilic bacteria having strong enzyme activity were selected among isolated strains. All selected strains reduced nitrate to nitrite and they utilized glucose, manose, manitol, and maltose as carbon source. From these MB15-2 was identified as Bacillus cereus, TB1, Bacillus licheniformis and TB9; Bacillus schlegelii.

• Journal of Environmental Health Sciences
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• v.27 no.1
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• pp.14-19
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• 2001

The physical and chemical transformation and reduction degree of food waste were investigated in a food waste reduction machine using thermophilic bacteria. The first operation of the reduction machine for grain, vegetables, fishes and flesh wastes proceeded during three weeks. The first and second reduction percentages of the wastes were 98.3% and 93.2%, respectively. The residue of food waste was composed of fruits, fish, and vegetables. The temperature distribution of the reduction machine ranged between 30 and 6$0^{\circ}C$ appropriate for growth of thermophilic bacteria. At initial stage the pH in the reduction machine decreased with organic acids produced, but increased as the organic acids decomposed by different thermophilic bacteria. In the reduction machine, the moisture content of the food waste was reduced from 80-90% to 10-20% after 24 hours, and the salinity of residue was 0.29% after the second operation. The degree of odor was most high between 2 and 4 hours.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.280-286
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• 2014

Four thermophilic bacterial species, including the iron-reducing bacterium Geobacillus sp. G2 and the sulfate-reducing bacterium Desulfotomaculum sp. SRB-M, were employed to integrate a bacterial consortium. A second consortium was integrated with the same bacteria, except for Geobacillus sp. G2. Carbon steel coupons were subjected to batch cultures of both consortia. The corrosion induced by the complete consortium was 10 times higher than that induced by the second consortium, and the ferrous ion concentration was consistently higher in iron-reducing consortia. Scanning electronic microscopy analysis of the carbon steel surface showed mineral films colonized by bacteria. The complete consortium caused profuse fracturing of the mineral film, whereas the non-iron-reducing consortium did not generate fractures. These data show that the iron-reducing activity of Geobacillus sp. G2 promotes fracturing of mineral films, thereby increasing steel corrosion.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.1976-1982
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• 2007

In the current studies, we characterized the degradation of a hot mixture of benzene and toluene (BT) gases by a thermophilic biofilter using polyurethane as a packing material and high-temperature compost as a microbial source. We also examined the effect of supplementing the biofilter with yeast extract (YE). We found that YE substantially enhanced microbial activity in the thermophilic biofilter. The degrading activity of the biofilter supplied with YE was stable during long-term operation (approximately 100 d) without accumulating excess biomass. The maximum elimination capacity ($1,650\;g{\cdot} m^{-3}{\cdot} h^{-1}$) in the biofilter supplemented with YE was 3.5 times higher than that in the biofilter without YE ($470\;g{\cdot} m^{-3}{\cdot} h^{-1}$). At similar retention times, the capacity to eliminate BT for the YE-supplemented biofilter was higher than for previously reported mesophilic biofilters. Thus, thermophilic biofiltration can be used to degrade hydrophobic compounds such as a BT mixture. Finally, 168 rDNA polymerase chain reaction-DGGE (PCR-DGGE) fingerprinting revealed that the thermophilic bacteria in the biofilter included Rubrobacter sp. and Mycobacterium sp.

• Microbiology and Biotechnology Letters
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• v.34 no.4
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• pp.363-367
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• 2006

Food wastes were decomposed into the Mugri (Isung Engineering, Korea), a food waste reduction machine, with adding sawdust of cryptomeria. Degradation effects were better when the machine worked at over 45$^{\circ}C$ than those at the lower temperature. Thermophilic bacteria were isolated from cryptomeria sawdust and the food waste products degraded by the machine. The isolates from cryptomeria sawdust were classified into 3 genera (Acinetobacter baumannii, Enterobacter sp. and Erwinia cypripedii) and almost all the isolates from the degraded products were partially identified as Bacillus sp. by 16S rDNA sequence analysis. The isolated thermophilic bacteria showed degradative enzyme activities. In the case of addition of the 30 thermophilic bacteria into the machine, degradation rate of food wastes was almost twice as high with increasing process temperature up to 6$^{\circ}C$.

• Journal of the Korean Wood Science and Technology
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• v.34 no.1
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• pp.68-78
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• 2006

The purpose of this study was to estimate the identification of thermophilic hacterial with fermentation of pig manure. To identify the characters of thermophilic bacteria related to fermentation at a high temperature condition, we selected 28 different kinds of original settling thermophilic bacteria that were sampled at different 23 areas. They were distributed 1$1{\times}10^5{\sim}10^8CFU$ at medium and the enzyme activity at $55^{\circ}C$ incubation condition, especially cellulase and a-amylase, were higher than those of $30^{\circ}C$. Partial sequencing data for 165 rDNA region were obtained from 28 samples representing 15 different genera. Bacillus subcilis, one of those bacteria, has endodermic spores at high fermented condition.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.31-34
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• 1990

Dibenzothiophene, crude oil and bunker C oil were used in the microbial desulfurization experiments using thermophilic and mesophilic strains of Desulfovibrio and Desulfotomaculum. Mesophilic Desulforvibrio desulfuricans M6 showed the degrees of sulfur removal about 42% and 17% from dibenzothiophene and crude oil, respectively. Thermophilic Desulfovibrio thermophilus showed the degrees of sulfur removal about 68% and 33% from dibenzothiophene and bunker C oil. The strains of Desulfotomaculum were much less efficient than strains of Desulfovibrio. The latter have more complex and stronger gydrogen metabolism. These results showed that desulfurization is closely related to the hydrogen metabolism of the sulfate reducing bacteria.

• Journal of the Mineralogical Society of Korea
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• v.23 no.4
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• pp.315-329
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• 2010

Characteristics of thermophilic bacteria and secondary materials on the pyrrhotite surface were investigated by using scanning electron microscopy (SEM). The thermophilic bacteria from an acid hot spring in Japan were incubated with pyrrhotite at $42^{\circ}C$, $52^{\circ}C$, and $62^{\circ}C$ respectively. SEM analysis of the reacted pyrrhotite showed that indigenous rod-shaped bacteria ranging from $0.4{\times}1.5{\mu}m$ to $0.3{\times}11.9{\mu}m$ in size were attached to the pyrrhotite surface at these temperatures with formation of secondary materials. Extracellular polymer substances were formed on the bacterial surface. We suggest that these polymers functioned as a capsule protecting bacteria from the extreme environment. Secondary materials such as elemental sulfur, Fe-hydroxide, S-Fe and O-P-Fe compounds were found on the pyrrhotite surface.