본 연구에서는 토마토를 일정한 기간(15일) 동안 저장하여 토마토의 품질인자인 감모율, 색상과 경도를 분석하고 비 파괴적 방법으로 토마토 경도를 측정한 결과로 경도와 감모율 사이의 상관관계를 분석하고 선형회귀모델을 도출하여 토마토 품질을 예측하고자 하였다. 그린하우스에서 재배된 ‘티와이250’품종을 수확한 후 일반 과실 종이 박스에 포장한 후 설정환경이 10℃, 90%RH인 항온항습챔버에 저장하여 3일 간격으로 경도, 무게와 색상 변화를 조사하였다. 15일간 저장 중 감모율은 저장기간이 증가함에 따라 증가하나 1.1% 정도에 머물러 단순히 감모율 인자로만 판단했을 때 토마토의 신선도 품질에 영향 끼치는 수준은 아니다. 색상변화 중 명도와 색조 각은 저장기간의 증가에 따라 감소하는 경향을, a/b와 ΔE는 증가하는 경향을 나타냈었고 일원분산분석결과를 볼 때 유의한 수준이었다(p<0.001). 경도는 저장기간이 증가함에 따라 감소하는 경향을 나타냈으며 저장 15일차에는 경도감소율이 40% 이상인 것으로 나타났다. 그리고 비 파괴방법으로 측정한 경도 값과 감모율 사이의 상관관계를 분석하여 선형회귀모델 WL=-0.0241×F+1.5213을 하였으며 모델의 추정치 오차는 ±0.231이었다. 이러한 결과에 비추어볼 때 수확 후 일정한 저장환경에서 비파괴적인 경도 측정을 통해 감모율을 추정하고 신선도를 판단하는 지표고 사용하는 것이 가능한 것으로 판단되었다.

The present study aimed to investigate the effects of low temperature on the growth, yield, quality, and biologically active compounds of strawberry and obtain basic information for developing a technology for stable growth of strawberry in greenhouses. Growth of strawberry, including leaf number, area, and length, plant height, and dry weight was better at the optimum growth temperature of 20℃ than at a lower temperature of 15°C. At the low temperature of 15°C, the cultivar 'Maehyang' was more tolerant and displayed better growth rate than 'Seolhyang'. At 15°C, the fruit production per week and fruit weight was lower than that at 20°C. In contrast, fruit length and diameter were not significantly different between the two growth temperatures. Growth temperature also did not affect the fruit color index, Hunter L, a, b value, or fruit firmness. However, the sugar content of strawberries grown at 15 was higher by 0.8 and 1.5 Brix for 'Seolhyang' and 'Maehyang', respectively, than of those grown at 20°C. There was no difference in the content of fisetin, a biologically active compound, for 'Seolhyang' at both growth temperatures, however, the fisetin content of 'Maehyang' was higher at 20°C than at 15 . Cinchonine and ellagic acid content of 'Seolhyang' was higher at 20°C than at 15 , whereas that of 'Maehyang' was higher at 15°C than at 20℃ . Quercetin content showed no significant differences with respect to growth temperature, however, it tended to increase at 20°C. The cinnamic acid content of 'Seolhyang' was higher at 15°C than at 20℃ , whereas that of 'Maehyang' increased at 20°C. Collectively, the biologically active compounds of strawberry were affected by growth temperature. Moreover, the content of these compounds tended to increase at 20°C, the optimum growth temperature, rather than at the sub-optimal growth temperature of 15°C.

Combustion of ethanol (EtOH) at low temperatures has been studied using titania- and silica-supported platinum nanocrystallites with different sizes in a wide range of 1~25 nm, to see if EtOH can be used as a clean, alternative fuel, i.e., one that does not emit sulfur oxides, fine particulates and nitrogen oxides, and if the combustion flue gas can be used for directly heating the interior of greenhouses. The results of H2-N2O titration on the supported Pt catalysts with no calcination indicate a metal dispersion of 0.97±0.1, corresponding to ca. 1.2 nm, while the calcination of 0.65% Pt/SiO2 at 600 and 900℃ gives the respective sizes of 13.7 and 24.6 nm when using X-ray diffraction technique, as expected. A comparison of EtOH combustion using Pt/TiO2 and Pt/SiO2 catalysts with the same metal content, dispersion and nanoparticle size discloses that the former is better at all temperatures up to 200℃, suggesting that some acid sites can play a role for the combustion. There is a noticeable difference in the combustion characteristics of EtOH at 80~200℃ between samples of 0.65% Pt/SiO2 consisting of different metal particle sizes; the catalyst with larger platinum nanoparticles shows higher intrinsic activity. Besides the formation of CO2, low-temperature combustion of EtOH can lead to many other pathways that generate undesired byproducts, such as formaldehyde, acetaldehyde, acetic acid, diethyl ether, and ethylene, depending strongly on the catalyst and reaction conditions. A 0.65% Pt/SiO2 catalyst with a Pt crystallite size of 24.6 nm shows stable performances in EtOH combustion at 120℃ even for 12 h, regardless of the space velocity allowed.

Activity of the noncontacted low temperature atmospheric pressure surface discharged plasma (LASDP) converts stable gas to ionized gas known as discharge or plasma. This ionized gas exhibits the antimicrobial activity. We examined the effects of 3 different storage treatments for 80 days on ‘Setoka’ : ambient storage (AS), low-tempperature storage (LTS), and low-temperature atmospheric pressure plasma+low-tempperature storage (PLTS). Total soluble solids showed no the significant differences between the 3 treatments. Acidity gradually decreased, and was 0.5% under AS after 30 days of storage. Fruit firmness increased by a few percent until 40 days of storage. Weight loss in AS was higher than for other treatments. After 80 days of storage, the decay ratio was significantly low in PLTS treatment: (AS, 50.5%; LTS, 5.6%; PLTS, 1.9%). In AS treatment, 73% of the rotten fruits were infected particularly with green and blue mold; however, only 1% of the rotten fruits were infected in case of PLTS treatment. In conclusion, LASDP treatment can pre

Omija-cheong, concentrated extracts from sugar-treated Omija fruit (Schisandra chinensis Baillon), is produced by traditional manner in Korea. The quality characteristics of Omija-cheong processed at low temperature with a pilot-scale were investigated to optimize the incubation time. With increasing incubation time in processing Omija-cheong, the pH level of Omija-cheong remained constant, while titratable acidity and organic acids increased. Fresh Omija fruits contained citric, malic and succinic acids, most of which were extracted into concentrated extracts after 37 days of incubation and reached to the stable concentration after 47 days of incubation. Titratable acidity in Omija-cheong gradually increased from 1.18% to 2.71%, and also was correlated with total concentration of organic acids. About 80% of supplemented sucrose for manufacturing Omija-cheong was converted into glucose and fructose until 68 days of incubation, and the composition of free sugars was maintained to be stable up to 138 days of incubation. The contents of total flavonoids and phenolic compounds in Omija-cheong were 24.1 mg-GAE/L and 1,635 mg-QE/L at 57 days of incubation, which were more than 9 and 5 times higher than those in Omija fruits, respectively. From the quality characteristics in processing Omija-cheong by low-temperature incubation, more than 60 days of incubation is required for the constant quality and value-added beverage.

This purpose of this study was to determine the best enrichment medium for rejuvenating and recovering Salmonella placed in cold temperature prior to the employment of the gold biosensor combined with a light microscopic imaging system. A mixture of nalidixic-resistant Salmonella Typhimurium and Enteritidis were inoculated onto chicken (1,000 CFU/chicken). After cold injury at 4℃ for 24 hr, Salmonella on chicken was enriched for 6 hr with six non-selective media including buffered peptone water broth, lactose broth, brain heart infusion broth (BHI), universal pre-enrichment broth, nutrient broth, and tryptic soy broth, and five selective media including brilliant green broth (BG), rappaport-vassiliadis R10 broth, selenite cystine broth, selenite broth, and tetrathionate brilliant green broth (TBG) for the comparison of Salmonella growth. Various concentrations of Salmonella (10, 50, 100, 500, and 1,000 CFU/chicken) were then enriched for 6 hr in both BHI and BG media to select the best media. BHI was selected as the most effective non-selective enrichment medium, while BG was selected as the most effective selective enrichment medium. Finally, BHI medium was selected as the most efficient enrichment medium for Salmonella growth injured from cold temperature during processing or storage.

The objective of this study was to evaluate the effects of low temperature-adapted Saccharomyces cerevisiae Y297 and fermentation temperatures on the quality of Yakju brewed. Physicochemical properties of Yakju brewed were compared pH, total acidity, ethanol, free amino acid, organic acid contents, and volatile flavor compounds in S. cerevisiae Y297 with control treatment. Cooked non-glutinous rice and saccharogenic amylase in koji were mixed with ethanol-producing yeasts and then fermented at 15℃, 20℃, and 25℃ for 20 days. Yakju brewed using the Y297 treatment showed the highest ethanol yield (17.9%) at 20℃. Expression of heat shock protein (HSP) 104 was evaluated by immunoblotting as an indication of adaptation to low temperatures (15℃); levels of the HSP104 protein were higher in the Y297 treatment than in the control. Organic acid analysis showed that the lactic acid content of Yakju brewed using the control was the highest at 25℃. Finally, free amino acid analysis showed that the Y297 treatment had a higher proportion of essential amino acids than the control. Overall, these results indicate that S. cerevisiae Y297 could be used as a suitable yeast for Yakju brewed under low temperature (15℃) condition.

Background : Plants live in restricted spaces that are constantly exposed to various environmental stresses. Under these stressful conditions, plants lead to biosynthesize specialized metabolites to adapt to environmental stresses. Here we investigate the effects of cold on the metabolome of tartaty buckwheat, focusing the flavonoid biosynthetic pathway. Methods and Results : From the metabolic profiling based on the GC-TOF-MS analysis, we identified the effect of cold on forty-four metabolites, including sugars, amino acids, and organic acids. Most of sugars and sugar derivatives remain nearly unchanged or slightly decreased in the plants grown at 25 ºC, whereas sugar and sugar derivative contents of cold-treated plants significantly increased, excepting galactose. Some of amino acid and amino acid derivatives contents decrease in cold-treated plants, whereas organic acid derived from tricarboxylic acid (TCA) cycle were increased the cold-treated plants compared with the plants grown at 25 ºC. Particularly, the contents of two anthocyanins, cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside, were significantly increased by cold treatment. Proanthocyanidins such as epicatechin and catechin were also significantly affected by cold. The expression of most flavonoid biosynthetic genes were significantly upregulated in cold-treated buckwheat seedling. Among the flavonoid biosynthetic genes, the expression of FtANS was notably upregulated in response to cold. Conclusion : By analyzing both primary metabolites and secondary metabolites of tartary buchwheat without or with cold, we showed that cold play a critical role in the modulation of the primary metabolites and flavonoid synthesis pathway in tartary buchwheat. Particularly, anthocyanin and proanthocyanidin biosynthetic pathways are strongly up-regulated in response to cold.

‘Jonathan’ apples are relatively small size which contributes to enhancing fruit consumption and gaining popularity. Thus, this study was carried out to evaluate the effects of AVG (aminoethoxyvinylglycine, ReTain®), sprayable 1-MCP (1-methylcyclopropene, HarvistaTM), and fumigation 1-MCP (SmartFreshTM) applications on fruit quality attributes and storability in ‘Jonathan’ apple fruits during cold-stored. The Jonathan fruits were dipped with either ReTain (75 mg/L) or Harvista (125 mg/L) solutions for 5 min, or fumigated with SmartFresh (1 mg/L) for 18 hr before storage at 0±1℃ for 75 days. Flesh firmness and titratable acidity remained higher in all pre-treated apples than control ones during cold storage period. Flesh firmness was higher for apples treated with ReTain and SmartFresh than samples treated with Harvista, while soluble solid content and respiration rate were not affected by sample pretreatment. Internal ethylene concentration (IEC) of all pretreated apples remained below about 4.5 μL/L during the entire storage period while that of control sample greatly increased to 10.29 μL/L. Ethylene production was much higher in control fruits than in treated ones during cold storage. These results indicated that ReTain and 1-MCP treatments would be considerably effective in retention of fruit quality attributes of ‘Jonathan’ apple during cold-stored.

Background: This study represents the first report that the anti-obesity activity of ethanol extracts of Aronia melanocarpa can be enhanced through ultrasonification at a frequency of 120 ㎑ at 60℃ (UE). Methods and Results: The amounts of cyanidin-3-O-galactose (cya-gal), a major anthocyanin in A. melanocarpa were higher by up to 402.4 ㎎/100 g, as compared with 221.4 ㎎/100 g and 322.1 ㎎/100 g, for hot water at 100℃ and 70% ethanol at 80℃ respectively. This result should cause the higher antioxidant activities of the UE than extract of hot water and ethanol in DPPH free radical scavenging. It was confirmed that the high antioxidant activity of UE could play an important role in inhibiting the production of proteins related to adipocyte differentiation, such as peroxisome proliferator activated receptor-γ (PPAR-γ) and sterol regulatory element binding protein 1 (SREBP1). Conclusions: Ultrasonification at a frequency of 120 ㎑ at 60℃ should result in better anti-obesity activity than that observed using other processes. It was also observed for the first time that the anti-obesity activity of A. melanocarpa was associated with its antioxidant activity, possibly due to the higher elution of intact cya-gal, owing to efficient low temperature ultrasonification extraction. These results could also be applied to improve other biological activities of medicinal herbs that contain many types of heat-labile bioactive substances.

Flower bud differentiation by temperature and photoperiod was investigated in early-, medium-, and late-maturing cultivars of radish (Raphanus sativus L.). Flower bud differentiation was induced by only day-length extension treatment (18 hr light/day) in early - and medium-maturing cultivars. Therefore, the early- and medium-maturing cultivars of radish were advanced the time of the flowering by the 2 weeks low temperature duration with day-length extension (18 hr light/day). The vegetative growth of early- and medium-maturing cultivar was the best by only day-length extension (18 hr light/day). However, late-maturing cultivar was needed for the flower bud differentiation and optimal vegetative growth not only long-day but also low temperature during 4~6 weeks at least. Our results suggest the optimal condition for flower bud differentiation in the each early-, medium-, and late-maturing cultivars of radish, which will be useful to develop breeding materials of radish.

The objectives of this study were to isolate and characterize low temperature adaptation yeast and to obtain suitable yeasts strains for manufacturing Yakju. In this study, we isolated 482 wild yeasts from fermented foods. Out of these, 5 yeast strains were selected based on increased growth at low temperature (15℃) and high β-glucosidase activity. To screen the aromatic level of isolates, media containing cerulenin and 5,5,5-trifluor-DL-leucine (TFL) were used. Y297 strain demonstrated tolerance against TFL and produced more than 13% alcohol. Y297 strain was identified a Saccharomyces cerevisiae based on the 26S rDNA gene sequences. Maximum cell growth was observed after 19 hr and 38 hr of incubation at 25℃ and 15℃, respectively. The exponential phase was followed by a lengthy stationary phase, at 15℃, when the cells remained high viable. Y297 strain demonstrated tolerance against alcohol (10%), glucose (60%) and salt(NaCl, 8%). β-glucosidase and esterase activity in Y297 were higher than those of controls at 15℃. Overall, these results indicated that using wild yeast strain, isolated from fermented food, affects the chemical characteristics of the brewed Yakju.

The efficacy of an experimentally designed cold chain container and a currently used styrofoam container was investigated with respect to important factors affecting the quality of fresh beef during storage under different conditions. The temperature in the TEPP-1 container was maintained at 5℃ using a phase change material (PCM) during transport and delivery. During storage in the TEPP-1 container, no significant difference was observed in pH of beef, but color decreased slightly, which does not affect the desire to purchase. After storage for 7 days, the rate of VBN and TBA in the TEPP-1 container, was lower than that in the TEPP-2 container. Drip loss was lower in the TEPP-1 container (0.87%) than in the TEPP-2 container (1.78%). No significant changes were observed in microbal count until 4 days in either of the containers, but after storage for 7 days, the count increased significantly. Microbial count in TEPP-1 was 6.65 log CFU/mL and that in TEPP-2 was 7.62 log CFU/mL. The results of sensory evaluations indicated that the overall acceptability of beef after storage for 7 days was better in the TEPP-1 container than in the TEPP-2 container. The EPS container was inferior in comparison with TEPP-1 and TEPP-2. It was impossible to continue the experiment using the EPS container after 3 days. These results suggest that the experimentally designed TEPP-1 container can be used for beef transport and delivery for 7 days without significantly affecting the quality of beef.

Background : Aruncus dioicus var. kamtschaticus, functional wild vegetable, is perennial herb and young leaves with soft texture are generally used as edible food. So the demand for the vegetable has increased recently. This study was carried out to determine the effects of temperature and shading on germination characteristics of A. dioicus. Methods and Results : The experiment was performed by temperature and shading treatments. Seed pre-treatment before the germination experiment was carried out by the storage in low temperature (4℃) under wet condition (LTW) for 0, 15, 30, 45 and 60 days and shading treatment were 35%, 50%, and 75% under control, BA (6-benzyladenine) and GA3 (gibberellic acid) condition for 24 hours. Increasing the length of the storage periods led to increases seed germination percent in low temperature (4℃) under wet condition (LTW), germination rate of A. dioicus seed was the highest at 15℃ with 60 days of seed pre-treatment. In the case of seeds pre-treatment with LTW, the more temperature went up, the more days to 50% of Germination of Final Germination Rate (T50) went down. As a result of surveying shading treatment, germination rate was the highest in control of 35% shading and the next higher was in control of 50% shading. Conclusions : It is concluded that the temperature and shading are important factors to produce A. dioicus. Also, We suggest these results as basic data of A. dioicus for sexual propagation.

미나리의 종자번식을 위해 각 기간에 따라 층적처리 한 후 세척 방법에 따른 발아율을 조사하였다. 층적처리 유무에 따른 발아율을 조사한 결과 층적처리를 하였을 때 69.3%로 층적처리를 하지 않았을 때 보다 약 1.4배 높게 발아 되었다. 층적처리 전, 수확한 종자를 음건 처리한 후 발아율을 비교한 결과, 음건처리를 하지 않은 종자의 발아율이 더 높게 조사되었다. 음건처리 하지 않은 종자를 저온저장고와 노지에 각각 2, 4, 8, 12주 동안 층적처리하여 저장한 결과, 노지에서 8주 동안 처리하였을 때 발아율이 평균 88%로 가장 높았다. 개화 후 40일 된 종자를 수확하여 모래층적처리 한 후 증류수와 농도 수준이 다른 sodium hypochlorite, vital oxide로 세척시간을 달리하여 발아율을 조사한 결과 증류수는 세척시간에 따른 발아율을 차이를 보이지 않았으나, sodium hypochlorite의 경우 0.5∼1.0% 용액으로 약 3∼5분 동안 세척하였을 때 발아율이 향상되었고, 2.0% 용액으로 세척하였을 때는 발아율이 저하되는 경향을 나타내었다. 또한 vital oxide 0.0005%의 농도로 60분 동안 세척하였을 때 발아율이 향상되었다. 본 연구 결과 기존의 열악한 환경에서 악성노동이 요구되는 영양번식에서 종자번식으로 전환하여 악성노동을 탈피하고, 기계화를 통한 노동력 감소 및 청정재배를 가능하게 하는 기초자료로 사용 가능할 것이며, 또한 종자발아가 어려워 재배화가 불가능한 많은 식물의 재배법 연구에 도움이 될 것으로 기대된다.

초롱꽃과 더덕속 식물인 더덕과 만삼의 종자 발아 특성 조사로 종자입모율 향상을 위한 재배기술 개발의 기초 자료로 활용하고자 온도별 종자발아실험, 식물생장조정제 처리 효과구명, 종자 보관에 따른 발아율 등을 조사하였다. 실험에 사용한 재료중 더덕 종자는 강원도 농업기술원 산채연구소에서 2013년 가을에 채종한 종자를 분양 받아 사용하였고, 만삼 종자는 강원도 정선 재배농가에서 2013년 가을에 채종한 종자를 분양 받아 풍선법으로 정선한 후 종자봉투에 봉입 후 실험실(20℃)에 두어 실험할 때마다 꺼내어 사용하였다. 저온처리 온도는 5℃의 냉장고를 사용하여 1주, 2주, 4주간 저온처리 후 각각 20, 25, 30℃의 항온조건으로 옮겨 매일 발아 상태를 조사하였다. 발아 촉진 목적으로 사용된 식물생장조정제는 3종으로 GA3는 정량 후 증류수에 넣어 교반하여 사용하였고, BAP와 키네틴은 용액 상태로 구입하여 시험 농도로 희석하여 사용하였다. 온도별 발아시험 결과 더덕은 20℃에서, 만삼은 15℃에서 각각 89%의 높은 발아율을 보였으며 30℃에서 더덕은 27%, 만삼은 2%의 낮은 발아율을 보였다. 5℃의 조건에서 더덕은 2주간, 만삼은 4주간 처리 후에 20, 25, 30℃에서 평균 발아율이 향상되었다. 더덕은 저온처리 기간에 배의 발달이 있었고 저온처리기간과 배의 발달과는 고도로 유의한 정의 상관관계가 있었다. 더덕과 만삼은 고온일수록 발아율이 저하되는 경향이 있었다. 만삼에서 GA3 처리농도와 발아율은 고도로 유의한 정의 상관관계를 보였다. 2주간 저온 처리 후 500ppm 복합처리에서 95%의 높은 발아율을 나타내었다. 그러나 더덕은 GA3 처리 후 발아율이 증가되지 않았다. 더덕, 만삼 종자에 사이토키닌 처리에서 처리농도와 발아율과는 고도로 유의한 부의 상관관계를 보였고 발아가 전혀 되지 않는 경우도 있었다. 더덕과 만삼 종자는 상온에서 1년간 보관 후 발아율이 크게 하락하였으나 저온냉장고에서 1년간 보관 후 더덕과 만삼의 발아율은 각각 75%, 79%로 높았다.

Skin anti-wrinkle activities of the stems and leaves of Abeliophyllum distichum Nakai were evaluated by theextracts obtained from various extraction processes such as using hot water at 100oC, 70% ethanol at 85oC, and 70% etha-nol with ultrasonication at 60oC The ultrasonicated extract showed 95.62% of the highest cell viability in addition of0.3㎎/㎖ of the extracts into the normal human fibroblast cell, CCD-986sk. For antioxidant activities, the extracts usingultrasonicated extract showed the highest DPPH free radical scavenging as 80.27%, followed by 75.88% and 62.44% for theextracts using ethanol extract and water extract. The ultrasonicated extract also showed the highest elastase inhibition activ-ity as 25.32%, compared to ethanol extract and water extract based method at 22.01% and 12.88%, respectively. MMP-1production was most effectively decreased down to 2908.1pg/㎖ with ultrasonicated extract while 6640.8pg/㎖ with waterextract and 3609.3pg/㎖ with ethanol extract, in addition of 0.3㎎/㎖. Collagen production was increased up to 154.7ng/㎖in addition of ultrasonicated extract, and followed by 121.4ng/㎖ and 31.2ng/㎖ for ethanol extract and water extract,respectively. These results indicate that the ethanol extract should have skin anti-wrinkling activities and can be improvedby the ultrasonication process that high energy input elute more amounts of bioactive substances eluting more amounts ofbioactive substances from the high energy input of ultrasonication.

A new lettuce cultivar ‘Misun’ (Lactuca sativa L.) with wrinkled traverse narrow elliptic and deep red leaf, which has late bolting and high yield. It was developed from a cross between ‘Yeoreum Jeocgchima’ (deep red leaf color) and ‘Yeoreumdukseomjeokchukmyeon’ (high yield). The cross and selection for advanced lines had been done by the pedigree method from 2001 to 2008. The advanced lines were evaluated for yield and adaptability at several locations in Korea (Gangwon-do, Gyeonggi-do, Chungcheongbuk-do, Jeollabuk-do, Gyeongnam-do, and Jeju-do) from 2009 to 2011 year. The ‘Misun’ has gray seed color and traverse narrow elliptic leaves. The shelf-life of ‘Misun’ was four weeks longer than ‘Dukseomjeokchukmyeon’at 4℃. The anthocyanin content of ‘Misun’ (88.32 mg/100 g) was higher than that of ‘Dukseomjeokchukmyeon’(74.78 mg/100g). The BSL (latucin+8-deoxylactucin+lactucopicrin) content of ‘Misun’ (5.0 ug/g, DW) is lower than that of ‘Dukseomjeokchukmyeon’(12.0 ug/g, DW). Compared to ‘Dukseomjeokchukmyeon’, marketable yield of ‘Misun’(289 g per plant) was 11% higher than that of it, showed good yield in fall season cultivation and has particularly improved expression of red leaf color at high temperature cultivation in the field. Furthermore, its taste is better, more crispy, and sweeter than those of ‘Dukseomjeokchukmyeon’. Thus, this new cultivar ‘Misun’ can be suitable for cultivation in low temperature during spring and fall season season.

유기성폐기물을 안정화시키는 동시에 바이오가스를 회수하는 혐기성소화기술은 지난 백여년 이상동안 많은 연구자들에 의하여 연구되어 온 전통기술로서 최근 지구온난화 문제가 전 세계적인 이슈로 부상하면서 새롭게 조명 받고 있다. 그러나, 혐기성소화기술은 여전히 메탄생성균의 느린 성장속도와 환경변화에 대한 민감성에 기인하여 20일 이상의 긴 체류시간을 필요로 하고 유기물 감량율과 메탄생성율이 높지 않다는 단점이 있다. 또한, 혐기성소화조는 성능을 유지시키기 위하여 중온(35℃) 또는 고온(55℃) 조건에서 운전하게 되는데, 소화조의 온도를 일정하게 유지시키기 위하여 가온하는데 많은 에너지를 필요로 한다. 그러나, 혐기성소화조를 저온에서 운전하게 될 경우 가온에 필요한 에너지를 절약할 수 있지만 생화학반응속도가 감소하여 소화성능이 크게 저하하는 결과로 이어지게 된다. 한편, 생물전기화학 혐기성소화(bioelectrochemical anaerobic digestion)는 재래식 혐기성소화가 가진 단점들을 극복하기 위하여 기존의 혐기성소화조에 산화전극과 환원전극으로 이루어진 생물전기화학장치를 설치하고 전극들에 일정한 전위를 인가함으로서 유기물의 혐기성분해 반응을 촉진시키는 기술이다. 본 연구에서는 하수슬러지를 대상으로 25℃의 저온조건에서 생물전기화학 혐기성소화성능을 평가하고, 중온조건에서의 결과와 비교하였다. 또한, 저온소화 성능에 대한 철염의 영향을 조사하였다. 본 연구는 교반기가 설치된 유효용량 12L의 재래식 혐기성소화조에 산화전극과 환원전극을 설치한 생물전기화학 혐기성소화조를 이용하여 수행하였다. 이때 산화전극은 흑연직물섬유의 표면에 탄소나노튜브를 전기영동전착법으로 고정시킨 것을 사용하였으며, 환원전극은 흑연직물섬유의 표면에 탄소나노튜브와 니켈을 동시에 고정시킨 것을 사용하였다. 준비된 생물전기화학 혐기성소화조의 산화전극과 환원전극 사이에는 외부의 직류전원을 이용하여 0.3V의 전압을 인가하였다. 초기운전을 위하여 S 하수처리장 혐기성소화조로부터 채취한 혐기성슬러지를 식종하였으며, Y 하수종말처리장에서 채취한 하수슬러지를 1일 1회 정량 주입하여 수리학적 체류시간은 20일로 유지하였다. 생물전기화학 혐기성소화조를 운전하는 동안 pH, VFA, COD 및 VS 그리고 바이오가스발생량 및 메탄함량과 전류의 변화 등을 관측하였다. 생물전기화학 혐기성소화조를 35℃의 중온에서 운전한 경우 초기운전기간 이후 정상상태에 도달하였을 때 비메탄발생율과 VS 감량은 각각 0.412L CH4/L/d 및 72.5%로서 대단히 우수한 소화성능을 보였다. 그러나, 생물전기화학 혐기성소화조를 저온에서 운전하였을 때 메탄발생량과 유기물 감량율은 전차감소하였으며, 정상상태에서 비메탄발생율과 VS 감량은 각각 0.354 L CH4/L/d 및 61.3%로서 중온조건의 85% 정도 소화성능을 보였다. 그러나, 유입슬러지에 철염을 첨가하여 생물전기화학 혐기성소화조를 운전하였을 때 메탄발생량과 VS 감량율은 빠르게 회복하였으며, 비메탄발생량과 VS 감량은 각각 403L CH4/L/d 및 69.8%로서 중온성능의 98% 가량의 성능을 보였다.