• 한국버섯학회지
• /
• 제12권2호
• /
• pp.88-95
• /
• 2014

Auricularia auricula-judae is an edible mushroom, which is known as wood ear, free ear, black ear mushroom, and free jelly fish. This study was carried out to obtain the basic information for mycelial culture conditions of Auricularia auriculajudae. According to colony diameter and mycelial density, the media for suitable mycelial growth were PDA and MCM. The optimum temperature for mycelial growth was $25{\sim}30^{\circ}C$. Carbon and nitrogen sources were mannose and malt extract, respectively. The optimum C/N ratio was in the range of 10 to 1 with 2% glucose. Other minor components for the optimal growth were thiamine-HCl and biotin as vitamins, succinic acid and lactic acid as organic acids, and $MgSO_4{\cdot}7H_2O$ and $KH_2PO_4$ as mineral salts.

• Environmental Engineering Research
• /
• 제25권1호
• /
• pp.80-87
• /
• 2020

Landfill waste decomposition generates a dark effluent named, leachate which is characterized by high organic matter content. To minimize these polluting effects, it becomes necessary to develop an effective landfill leachate treatment process. The objective of this study was to evaluate the performance of an innovative approach based on air stripping, anaerobic digestion (AD) and aerobic activated sludge treatment. A reduction of 80% of ammonia and an increase of carbon to nitrogen ratio to 25 were obtained, which is a suitable ratio for AD. This latter AD was performed in fixed bed reactor with progressive loading rate that reached 2 and 3.2 g COD/L/d for the raw and diluted leachate (1:2), respectively. The anaerobic treatment led to significant removal of chemical oxygen demand (COD) and biogas production, especially for the diluted leachate. The COD removal was of 78% for the raw leachate and a biogas production of 4 L/d with 70% methane content. The use of the diluted leachate led to 81% of COD removal and 7 L/d biogas with 75% methane content. It allowed a removal of 77% COD and more than 97% of the organic compounds present in the initial leachate sample.

• 한국재료학회지
• /
• 제33권12호
• /
• pp.530-536
• /
• 2023

The theoretical capacity of silicon-based anode materials is more than 10 times higher than the capacity of graphite, so silicon can be used as an alternative to graphite anode materials. However, silicon has a much higher contraction and expansion rate due to lithiation of the anode material during the charge and discharge processes, compared to graphite anode materials, resulting in the pulverization of silicon particles during repeated charge and discharge. To compensate for the above issues, there is a growing interest in SiO_x materials with a silica or carbon coating to minimize the expansion of the silicon. In this study, spherical silica (SiO₂) was synthesized using TEOS as a starting material for the fabrication of such SiO_x through heating in a reduction atmosphere. SiO_x powder was produced by adding PVA as a carbon source and inducing the reduction of silica by the carbothermal reduction method. The ratio of TEOS to distilled water, the stirring time, and the amount of PVA added were adjusted to induce size and morphology, resulting in uniform nanosized spherical silica particles. For the reduction of the spherical monodisperse silica particles, a nitrogen gas atmosphere mixed with 5 % hydrogen was applied, and oxygen atoms in the silica were selectively removed by the carbothermal reduction method. The produced SiO_x powder was characterized by FE-SEM to examine the morphology and size changes of the particles, and XPS and FT-IR were used to examine the x value (O/Si ratio) of the synthesized SiO_x.

• Korean Chemical Engineering Research
• /
• 제53권3호
• /
• pp.327-332
• /
• 2015

A large amount of dye wastewater poses a threat to environmental safety. Disperse blue, an anthraquinone dye that is widely used in textile dyes, is difficult to degrade in wastewater. In this work, one fungus was screened according to the decolorization rate of disperse blue. The fungus was identified and named Aspergillus XJ-2 on the basis of its morphological characteristics and 18s rDNA. Response surface method was used to optimize culture conditions for A. XJ-2. The optimum values of obtained responses were as follows: temperature, $35^{\circ}C$; pH, 5.2; carbon-to-nitrogen ratio, 30:5.5; and rotation ratio, $175r{\cdot}min^{-1}$. Under optimized conditions, the decolorization rate of A. XJ-2 was up to 94.8% in 48 h.

• KSBB Journal
• /
• 제10권4호
• /
• pp.349-356
• /
• 1995

하수처리장의 활생오니를 분리원으로 하여 수십종의 PHA 생산균을 분리하였다. 일반적으로 hy­d droxyvalerate monomer unit의 전구물질로 알려져 있지않은 glucose로부터 비교적 많은 PHA를 생산 하는 균주를 공시균으로 선정하여 형태학척, 배양적, 생리학적 제 특성을 검토한 결과 Pseudomonas 속으 로 통정되었다. 균체 생육을 위한 최적 배양온도 벚 배양 pH는 각각 $37^{\circ}C$와 7.0이었으며, 최적 탄소원 으로셔 glucose 1 %, 최적 질소원으로서 $(NH_4)_2SO_4$ 0.2%, K1HPO. 0.3%, $KH_2PO_4$ 0.45% 였다. 최적 P PHA 생산조건을 조사하기 위하여 2단계 배양법을 이용하였다 PHA 생산은 배지성분중 $NH_4, O_4$, Mg가 결핍되 였을 때 향상되었고, 그중 $NH_4$, 의 결핍시 PHA 축적률과 HV monomer의 함량이 가장 높았다. C/N molar ratio 95.2에서 PHA 축적률이 가장 높았다. 공시균주 Pseudomonas sp. HJ는 alkane, alkanoic acid, alcohol을 탄소원으로 하여 P PHB/HV를 생산하였다. PHA의 생산량과 HV monomer의 함량은 이용된 기질에 따라 다양하였으며, 특히 hexadecane와 propiOnate를 탄소원으로 하였을 때 PHA중의 HV monomer의 함량이 49~74mol %로 매우 높았다. IH-NMR로셔 공시균으로 부터 분리정제된 PHA의 조성을 분석한 결과 PHB/ H HV copolymer임을 알 수 였였다

• 동아시아식생활학회지
• /
• 제23권1호
• /
• pp.44-52
• /
• 2013

This study investigated hepatic functional improvement and anti-fibrotic effects of water extracts of black tea. Male Sprague-Dawley rats were divided into four groups (normal, control, and two experimental subgroups: Ba, Bb) and observed for 3 weeks. Liver fibrosis in rats developed from carbon tetrachloride ($CCl_4$) administration, except for the normal group. Except for the normal and control group, the two experimental subgroups were fed water extracts of black tea. The food efficiency ratio significantly increased in the experimental group compared to the control group. The experimental group had a significantly lower liver weight compared to the control group. The ratio of liver weight to body weight was significantly lower in the experimental group than the control group. The levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, blood urea nitrogen, and low-density lipoprotein-cholesterol in serum significantly decreased in the experimental group compared to the control group. The values of hydroxyproline and malondialdehyde in liver were even lower in the experimental group than the control group. In observations on liver histology, weaker inflammation and fibrosis were observed in the experimental group compared to the control group. In conclusion, water extracts of black tea help hepatic cells keep their functions, restraining and protecting the liver from impairments caused by $CCl_4$ administration, and can be effective as anti-fibrotic agents.

• 한국분무공학회지
• /
• 제26권1호
• /
• pp.40-48
• /
• 2021

Lean combustion was applied to improve the thermal efficiency and emission in a single-cylinder, spark-ignition engine fueled with syngas. Under naturally aspirated conditions, the lean combustion significantly improved the thermal efficiency compared to the stoichiometric combustion, mainly due to the reduction in heat transfer loss. Intake air boost was applied to compensate the low power output of the lean combustion. The gross indicated power of 24.8 kW was achieved by increasing the intake pressure up to 1.6 bar at excess air ratio of 2.2. The nitrogen oxides showed near zero level, but the carbon monoxide emission was significant.

• Journal of Microbiology and Biotechnology
• /
• 제21권7호
• /
• pp.739-745
• /
• 2011

During the production of grape wine, the formation of thick leathery pellicle/bacterial cellulose (BC) at the airliquid interface was due to the bacterium, which was isolated and identified as Gluconacetobacter hansenii UAC09. Cultural conditions for bacterial cellulose production from G. hansenii UAC09 were optimized by central composite rotatable experimental design. To economize the BC production, coffee cherry husk (CCH) extract and corn steep liquor (CSL) were used as less expensive sources of carbon and nitrogen, respectively. CCH and CSL are byproducts from the coffee processing and starch processing industry, respectively. The interactions between pH (4.5-8.5), CSL (2-10%), alcohol (0.5-2%), acetic acid (0.5-2%), and water dilution rate to CCH ratio (1:1 to 1:5) were studied using response surface methodology. The optimum conditions for maximum BC production were pH (6.64), CSL (10%), alcohol (0.5%), acetic acid (1.13%), and water to CCH ratio (1:1). After 2 weeks of fermentation, the amount of BC produced was 6.24 g/l. This yield was comparable to the predicted value of 6.09 g/l. This is the first report on the optimization of the fermentation medium by RSM using CCH extract as the carbon source for BC production by G. hansenii UAC09.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
• /
• pp.300-303
• /
• 2012

에너지 소비 증가에 따른 이산화탄소 배출로 인한 지구 온난화가 심각하다. 이산화탄소와 산화질소를 배출하지 않으며, 수소로부터 에너지를 생성하는 메커니즘의 개념에 대한 연구를 수행하였다. 수소를 포함하고 있는 수소화물의 한 종류인 소듐 보로하이드라이드($NaBH_4$)와 과산화수소를 반응시켜 수소와 산소 간의 연소 반응을 통한 열에너지 생성 메커니즘에 대한 개념을 도출하였다. 수소화물을 물에 용해시켜 액체 상태로 과산화수소와 반응시킬 경우, 연료에 해당하는 수소화물 수용액과 과산화수소의 질량대비가 0.89일 때 최대 단열 반응 온도가 1795 K까지 상승할 수 있음을 예측하였다.

• 한국유기농업학회지
• /
• 제5권1호
• /
• pp.111-124
• /
• 1996

Composting of animal residues with weeds and waste papers as bulking agents was tested. Coorperative form of work with farmers, students, cleaning women and members of citizens' movement was attempted. The responses of participants for composting, through it's laboriousness and dirtiness, were favorable with feeling of doing good for social services. The temperature of compost was raised up to 83 $^{\circ}C$. in spite of cold winter weather after turning. The pH, water content, total carbon, total nitrogen and C/N ratio showed the similarity to stability steps of other usual composts. The contents of heavy metals were low except Cu in comparison with standard levels. The uses of waste papers as a bulking agent for composting of animal residues, especially for organic farming, would need more diverse investigations.