• Journal of Microbiology and Biotechnology
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• v.24 no.11
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• pp.1484-1489
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• 2014

A novel esterase gene, est01, was successfully unearthed from a biogas digester microbiota metagenomic library. The 1,194 bp est01 gene encodes a protein of 44,804 Da (designated Est01). The amino acid sequence of Est01 shows only moderate (33%) identity to a lipase/esterase. Phylogenetic analysis and biochemical characterization confirmed that Est01 is a new member of family VIII esterases. The purified Est01 from recombinant Escherichia coli BL21 (DE3) showed high hydrolytic activity against short-chain fatty acid esters, suggesting that it is a typical carboxylesterase rather than a lipase. Furthermore, the Est01 was even active at $10^{\circ}C$ (43% activity remained), with the optimal temperature at $20^{\circ}C$, and had a broad pH range from 5.0 to 10.0, with the optimal pH of 8.0. These properties suggest that Est01 is a cold-adaptive esterase and could have good potential for low-temperature hydrolysis application.

• Journal of Korean Society on Water Environment
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• v.27 no.6
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• pp.769-775
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• 2011

An experimental study of biofilm nitritation system for high-strength ammonium wastewater has been carried out to examine the temperature effect on different organic and solid concentration. Operating temperature varied from $35^{\circ}C$ to $15^{\circ}C$. The influent N concentration of identical three reactors was adjusted to about $300mg\;NH_4-N/L$. A control unit fed with a synthetic wastewater, while the others were fed with reject water which is consisted of the supernatant of both digester and thickener. The results indicated that nitrite accumulation was stable in temperature range of $35^{\circ}C$ to $25^{\circ}C$. However, nitritation was significantly reduced at below $20^{\circ}C$. Free ammonia (FA) and free nitrous acid (FNA) were major inhibitors to the nitrite oxidizer for nitrite accumulation in lower temperature. From the estimation of temperature coefficient (${\Theta}$) of biofilm and suspended nitritation system, biofilm nitritation system could absorb the negative temperature effect compared with suspended nitritation system.

• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.107-117
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• 1984

This study was made to evaluate the temperature effects on anaerobic digestion of swine manure. A laboratory single-stage, high-rate, anaerobic digester was operated at 10, 20 and 30 day's HRT at the temperature of 35$\circ$C or 55$\circ$C. The conclusions from this study are as follows: (1) COD and BOD reductions were similar in both the mesophilic and thermophilic digestions. (2) With thermophilic digestion, volatile reduction increased to 67%, as compared with 60% of mesophilic digestion. With thermophilic digestion, the pH increased to 8.5 as compared with 8.0 of mesophilic digestion. With thermophilic digestion, the concentration of volatile acid increased to 763 mg/l, as compared with 250 mg/l of mesophilic digestion. While the gas was produced by mesophilic digestion at 0.74m$^3$/kg of VS fed, it increased to 0.87 m$^3$/kg VS fed by thermophilic digestion. The refractory VS was about 25% of the infiuent VS.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.1
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• pp.139-145
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• 1993

Biogas created from animal waste is a precious energy source. A practical and successful utilization of the biogas is not easy, because there lie some difficulties in biogas production and facilities investment. In this study, the requisites for a successful biogas utilization were discussed. The production results obtained in the previous operation of anaerobic digestion plant were used for the simulation. When the slurry heating was designed for constant biogas generation, depreciation costs of the facilities amounted 1,175,000 yen per year, and biogas productions at $24.5^{\circ}C$, $30.0^{\circ}C$ and $35.5^{\circ}C$ were $16.8m^3$, $17.6m^3$ and $25.1m^3$, respectively. Removal ratios of organic matters were not so high. At $35.5^{\circ}C$, energy value of the biogas produced was estimated 125.5 Mcal per day, and the following heat loss (y Mcal/day) was brought about by the temperature difference ($X^{\circ}C$) between the digester and atmosphere; y = 0.769X - 5.375. The costs of biogas production per cow were assumed to decrease according to enlargement of feeding scale, especially on scales of more than 30 cows. On recent levels of costs and prices of energy in Japan, they were nearly equal to 2 to 3 fold of the price of municipal mixed gas when a anaerobic digester was compulsorily heated and kept at $30.0^{\circ}C$ or $35.5^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.4
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• pp.325-335
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• 1985

Biogas production from agricultural wastes were summarized as follows: 1. Biogas Generation Characteristics of Various Manures and Residues a. Gas yield from crop residues like rice straw, rice hull, corn stalk and coconut husk can be improved by addition of animal manures. b. Gas yield from coconut husk can be improved through aerobic fermentation for at least one week before loading in the digester. c. Gas yield from fresh rice straw is better than from pre-fermented one, whether alone or in combination with animal manures. d. Initial study has shown that fresh azolla can be substituted for animal manures in manurerice straw combinations and gas yield derived based on unit volatile solids loaded is actually better than for manure-residue combinations. e. Gas production is highly sensitive to substrate pH and becomes almost nil at a pH of below 6. 2. Effect of ambient conditions and other factors on biogas production in a house hold-size digester. a. Results showed that compaction of rice straw in straw-manure combination can reduce gas yield compared with loosely mixed straw. b. The effective gas production period extended to 70 days using freshly threshed rice straw and fresh cattle manure as feed material. c. Underground and above ground digesters with shade have relatively more stable substrate temperature than aboveground exposed digesters. This relative temperature instability may likely be the reason for lower gas yield for the exposed aboveground digester loaded with loose straw-cattle manure substrate, compared with the underground digester with the same substrate. 3. Economic Analysis a. Based on prevailing costs of fuel, materials, and labor in the Philippines, biogas produced from the household size system is cheaper than either LPG or kerosene. b. If other benefits like organic fertilizer, pollution control and convenience are considered, biogas will surely be the best alternative fuel source.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.214-222
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• 2012

Several acidogenesis batch tests, and BMP (Biochemical Methane Potential) with food waste leachate was tested at various organic loading rates (OLRs) on the mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) conditions. In acidogenesis batch test, VS removal efficiencies were 27.3% and 30.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. Removal efficiency of VS at $55^{\circ}C$ was higher than that at $35^{\circ}C$. With decrease in VS, SCOD increased as reaction time increased. Solubilization efficiency of VS were 27.4% and 33.4% at each reaction temperature within 4 days acid fermentation. Methane yield were 461 and 413 $mLCH_4/gVS$ at mesophilic and thermophilic BMP test, respectively. SCOD solubilizations in the themophilic acid fermenter showed 8~17% higher than those in the mesophilic fermenter. COD removal efficiency showed higher in the mesophilic acid fermenter at low organic loading rate. While at high organic loading rate, it was higher in the thermophilic acid fermenter. VS removal efficiency was higher at the mesophilic temperature, however, it decreased at OLR higher than 6 kg $COD/m^3{\cdot}day$. On the contrary, VS removal efficiency did not decrease but maintain at thermophilic temperature. The amount of methane gas generated from mesophilic methanogenesis digester was 12.6, 21.6, 27.4 L/day at OLR of 4, 5, 6 $COD/m^3{\cdot}day$, respectively. The amount of methane gas generated from themophilic methanogenesis digester was 14.3, 20.6, 25.2 L/day at each OLR, respectively, which is about 15~20 L/day lower than those generated at mesophilic digester.

• Journal of Microbiology and Biotechnology
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• v.23 no.3
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• pp.382-389
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• 2013

Propionate is an important intermediate product during the methane fermentation of organic matter, and its degradation is crucial for maintaining the performance of an anaerobic digester. In order to understand the effect of temperature on propionate degradation, an upflow anaerobic sludge blanket (UASB) reactor with synthetic wastewater containing propionate as a sole carbon source was introduced. Under the hydraulic retention time (HRT) of 10 h and influent propionate of 2,000 mg/l condition, propionate removal was above 94% at 30-$35^{\circ}C$, whereas propionate conversion was inhibited when temperature was suddenly decreased stepwise from $30^{\circ}C$ to $25^{\circ}C$, to $20^{\circ}C$, and then to $18^{\circ}C$. After a long-term operation, the propionate removal at $25^{\circ}C$ resumed to the value at 30- $35^{\circ}C$, whereas that at $20^{\circ}C$ and $18^{\circ}C$ was still lower than the value at $35^{\circ}C$ by 8.1% and 20.7%, respectively. Microbial community composition analysis showed that Syntrophobacter and Pelotomaculum were the major propionate-oxidizing bacteria (POB), and most POB had not changed with temperature decrease in the UASB. However, two POB were enriched at $18^{\circ}C$, indicating they were low temperature tolerant. Methanosaeta and Methanospirillum were the dominant methanogens in this UASB and remained constant during temperature decrease. Although the POB and methanogenic composition hardly changed with temperature decrease, the specific $COD_{Pro}$ removal rate of anaerobic sludge (SCRR) was reduced by 21.4%-46.4% compared with the control ($35^{\circ}C$) in this system.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.1-8
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• 1997

Carbon monoxide (CO)-utilizing acetogens were enriched and KIST612 isolated from anaerobic digester fluid was selected for its abilities to tolerate high CO and acetate concentration. The isolate KIST612 was identified as Eubacterium limosum based on the morphological and biochemical characteristics, G+C content of DNA and 16S rRNA sequence analysis. E. limosum KIST612 produced acetate and butyrate from CO. The optimum temperature and pH for the growth and acids formations were 37$\cdot $C and 7.0, respectively. The growth rate and acids productivity of E. limosum KIST612 were higher than those of any other known acetogens when CO was used as the sole energy and carbon source.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.4
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• pp.54-62
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• 1997

Disposal of blue crab wastes represents a significant problem to processors, who are limited with respect to acceptable disposal alternatives. Anaerobic bioconversion technology was investigated to determine an environmentally sound and economic disposal method for these wastes. In the study ultimate methane yield for total crab solid waste was $0.180m^3/kg$ VS added and biodegradation rate constant was $0.15day^{-1}$. Methane yield of the bench-scale reactor operated on similar feedstock was $0.189m^3/kg$ VS added and biodegradation rate constant was $0.06day^{-1}$. These results indicate that anaerobic bioconversion of blue crab wastes was technically feasible. Use of anaerobic bioconversion technology can be an attractive option for blue crab processing waste management. The by-product methane gas could be used for maintainign a number of processing operations (i.e., heat for cooking, or keeping temperature of digester constant).

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.1-7
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• 2023

Recently, in the semiconductor industry, memory device market is focusing on producing ultra-thin wafers for high integration. In the wafer manufacturing process, wafers after backgrinding and CMP process must be picked up as individual dies and subjected to be peeled off from the dicing tape. However, ultra-thin dies are vulnerable to the possibility of breakage and failure in their thickness and size. This research studies the mechanism of peeling a die with a high-aspect ratio using a thermopneumatic method instead of a die ejector with physical pins. Setting compressed air and the temperature as main factors, we determine the success of the digester using thermopneumatic system and analyze the good die to find the possibility of making mass-production equipment.