• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.856-862
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• 2015

The objective of this study was to optimize the slurry contents and salt concentrations for ethanol production from hydrolysates of the seaweed Eucheuma spinosum. A monosaccharide concentration of 44.2 g/l as 49.6% conversion of total carbohydrate of 89.1 g/l was obtained from 120 g dw/l seaweed slurry. Monosaccharides from E. spinosum slurry were obtained by thermal acid hydrolysis and enzymatic hydrolysis. Addition of activated carbon at 2.5% (w/v) and the adsorption time of 2 min were used in subsequent adsorption treatments to prevent the inhibitory effect of HMF. The adsorption surface area of the activated carbon powder was 1,400-1,600 m²/g and showed selectivity to 5-hydroxymethyl furfural (HMF) from monosaccharides. Candida tropicalis KCTC 7212 was cultured in yeast extract, peptone, glucose, and high-salt medium, and exposed to 80, 90, 100, and 110 practical salinity unit (psu) salt concentrations in the lysates. The 100 psu salt concentration showed maximum cell growth and ethanol production. The ethanol fermentations with activated carbon treatment and use of C. tropicalis acclimated to a high salt concentration of 100 psu produced 17.9 g/l of ethanol with a yield (Y_EtOH) of 0.40 from E. spinosum seaweed.

• 한국수산과학회지
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• 제34권2호
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• pp.84-90
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• 2001

저분자 alginate인 HAG-10, HAG-50, HAG-100 및 alginate를 랫드에 장기간 섭취시켰을 때, 분변의 무게와 수분함량, 단백질과 지방함량, pH, VBN 및 단쇄지방산을 측정하여 소화생리특성에 미치는 영향에 대하여 검토하였으며, 그 결과를 요약하면 다음과 같다. 랫드분변의 무게와 수분함량의 변화는 alginate에서 가장 높은 증가를 보였고, 다음으로 HAG-100, HAG-50이었으며 HAG-10은 투여전과 거의 변화가 없었다. 분변의 단백질과 지방함량은 $5\%$ HAG-50에서 가장 높았고, 그 소화율은 $5\%$와 $10\%$ HAG-50에서 유의적으로 현저히 저하하였다. 분변의 pH는 $5\%$와 $10\%$ HAG-50에서 급격하게 저하하였으나, $10\%$ HAG-100과 alginate에서는 오히려 급격히 증가하는 경향을 나타내었다. VBN은 $10\%$ HAG-10, HAG-50 모두 그리고 $1\%$와 $5\%$ HAG-100에서 뚜렷한 저하를 보였으나, $10\%$ HAG-100 및 $5\%$와 $10\%$ alginate는 반대로 급격히 증가하였다. 단쇄지방산의 변화는 $5\%$와 $10\%$ HAG-50에서 n-butyric acid가 증가하였고, propionic acid와 acetic acid는 반대로 현저히 감소하였다. 이상의 결과로부터, HAG-50은 랫드 분변의 pH와 VBN을 현저히 저하시켰으며, 단쇄지방산중 n-butyric acid를 증가시키고 propionic acid와 acetic acid를 유의적으로 감소시켰으므로, 랫드의 소화생리특성을 개선시키는 데 있어서 효과적인 저분자 alginate라고 사료된다.

• 상하수도학회지
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• 제22권4호
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• pp.449-454
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• 2008

Some pretreatment methods have been proposed to enhance the biodegradability and to shorten the hydrolysis reaction time. By means of efficient pretreatment the suspended solids (SS) can be made of better accessible for the anaerobic bacteria. There are several ways how this can be accomplished, which include biological, mechanical, thermal, and chemical methods. For the sludge solubilization using the cavitation phenomenon, we have tried to develop a pretreatment process consisted of a reactor and pumps. The objectives of this study were to develop a advanced wastewater treatment consisted of IABR and the cavitation with PGA. The most effective removal for organic matter and nutrients were occured when both cavitation pretreatment and ${\gamma}$-PGA were applied at the IABR process. Only small portion of ${\gamma}$-PGA at a rate of 1.38mg/L, was enough to improve sedimentation ability, SS removal efficiencies, and sludge volume reduction. After the sludge solubilization by the cavitation, SCOD increased to 193% and SS decreased to 36%. The removal ratio of BOD was 94.5%, T-N removal ratio was 85.5% and T-P removal ratio was 84.9%. The combination process of the IABR with the cavitation and PGA addition seems to be very effective alternative wastewater treatment process.

• 한국수산과학회지
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• 제19권1호
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• pp.10-19
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• 1986

A study on the rapid fermentation of fish sauce has been carried out for effective utilization of sardine. The frozen sardine was thawed at room temperature, chopped, homogenized with equal amount of water and then hydrolyzed by addition of commercial proteolytic enzymes such as bromelain, papaya protease, ficin and a enzyme mixture under different conditions of hydrolysis. The effect of wheat gluten for masking fishy odor and color development during thermal treatment were also tested. The reaction mixture was heated for 30 minutes at $100^{\circ}C$ for enzyme inactivation, pasteurization and color development and then centrifuged for 20 minutes at 4,000 rpm. Finally, table salt and benzoic acid were added for bacteriostatic effect. The results were summarized as follows ; 1. The hydrolyzing temperature, time, pH and the concentration of enzymes based on the weight of whole sardine for optimal hydrolysis were as follows: autolysis, $52.5^{\circ}C$, 4 hours, pH 8.0: with $0.25\%$ bromelain, $52.5^{\circ}C$, 4 hours, pH 6.6 :with $0.25\%$ ficin, $52.5^{\circ}C$, 4 hours, pH 6.8: with $0.3\%$ papaya protease, $52.5^{\circ}C$, 4 hours, pH 6.6: with $6\%$ enzyme mixture, $52.5^{\circ}C$, 4 hours, pH 6.9, respectively. But pH control was not much beneficial in increasing yield. 2. The hydrolytic reaction of chopped sardine with proteolytic enzymes could be interpreted as a first order reaction that devided into 2 periods with different reaction rate constsnts. $Q_{10}$ values of the first period prior to 4 hours were 1.23 to 1.31, and those of post 4 hours were 1.25 to 1.55. The corresponding activation energies were $1.81{\times}10^4\;to\;2.34{\times}10^4\;kJ/kmol$ and $1.92{\times}10^4\;to\;3.77{\times}10^4\;kJ/kmol$, respectively. 3. The reasonable amount of $75\%$ vital wheat gluten for addition was $9\%$ of chopped sardine. 4. The dark brown color was mainly developed during the thermal treatment for 30 minutes at $100^{\circ}C$ and not changed during storage.

• Journal of Microbiology and Biotechnology
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• 제22권6호
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• pp.818-825
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• 2012

Keratinases are exciting keratin-degrading enzymes; however, there have been relatively few studies on their immobilization. A keratinolytic protease from Chryseobacterium sp. kr6 was purified and its partial sequence determined using mass spectrometry. No significant homology to other microbial peptides in the NCBI database was observed. Certain parameters for immobilization of the purified keratinase on chitosan beads were investigated. The production of the chitosan beads was optimized using factorial design and surface response techniques. The optimum chitosan bead production for protease immobilization was a 20 g/l chitosan solution in acetic acid [1.5% (v/v)], glutaraldehyde ranging from 34 g to 56 g/l, and an activation time between 6 and 10 h. Under these conditions, above 80% of the enzyme was immobilized on the support. The behavior of the keratinase loading on the chitosan beads surface was well described using the Langmuir model. The maximum capacity of the support ($q_m$) and dissociation constant ($K_d$) were estimated as 58.8 U/g and 0.245 U/ml, respectively. The thermal stability of the immobilized enzyme was also improved around 2-fold, when compared with that of the free enzyme, after 30 min at $65^{\circ}C$. In addition, the activity of the immobilized enzyme remained at 63.4% after it was reused five times. Thus, the immobilized enzyme exhibited an improved thermal stability and remained active after several uses.

• 자원리싸이클링
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• 제24권2호
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• pp.46-54
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• 2015

본 연구는 하수처리장에서 발생되는 생슬러지와 잉여슬러지를 대상으로 열적가용화 공정의 적용성을 평가하였다. 열적가용화 효율 및 특성평가는 각 슬러지를 대상으로 $100{\sim}220^{\circ}C$ 온도범위에서 30분간 전처리를 수행한 후 실시되었다. 그 결과, 가용화 온도가 상승함에 따라 $SCOD_{Cr}$, $NH_4{^+}$, VFAs 농도가 증가하는 경향을 확인할 수 있었다. 또한 COD 가용화효율 평가 결과, 온도 상승에 비례하는 경향이 나타나 열적가용화에 의해 가수분해 및 산발표 단계를 촉진시킨 것으로 판단된다. BMP (Biochemical Methane Potential) 실험을 통해 생슬러지의 경우 $220^{\circ}C$에서 가장 높은 biogas 생산량을 보여주었으나, 증가율은 5.6%로 열적가용화에 의한 효과가 미미한 것으로 나타났다. 반면 잉여슬러지의 경우 최대 38.8% ( $180^{\circ}C$) 증가하여, 열적가용화 공정은 잉여슬러지에 대한 적용성이 더욱 우수한 것으로 나타났다.

• 한국미생물·생명공학회지
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• 제44권2호
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• pp.145-149
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• 2016

해조류 중 홍조류인 K. alvarezii로부터 동시 당화 발효(SSF)를 위한 효소 당화 및 균 배양 온도를 검토하고, 기존의 동시 당화 발효(SSF) 를 개선하기 위해 2단계 동시 당화 발효(SSF)를 수행하였다. 효소 당화와 균 성장 온도를 고려하였을 때 동시 당화 발효(SSF)에 적용하는 배양 온도는 40°C를 선택하여 실험을 진행하였다. 비순치 효모(wild type)와 고농도 갈락토오스에 순치한 효모(adapted yeast to galactose)를 이용한 동시 당화 발효(SSF)를 실시한 결과 발효 156시간에 9.1 g/l의 에탄올 수율(Y_EtOH) 0.24와 10.2 g/l의 에탄올 수율(Y_EtOH) 0.27을 나타내었다. 이러한 기존의 동시 당화 발효(SSF)를 개선한 2단계 동시 당화 발효(SSF)는 에탄올 생산 수율이 0.27에서 0.35로 27.5% 증가하였으며, 에탄올 발효 시간도 156시간에서 96시간으로 61.5% 감소하였다. 이러한 연구결과는 해양 바이오매스인 해조류로부터 바이오연료 생산과정에 있어 기초적인 정보를 제공할 것이다.

• KSBB Journal
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• 제29권6호
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• pp.414-420
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• 2014

The seaweeds with high carbohydrate ratio Gelidium amansii, Saccharina japonica and Enteromorpha intestinalis were used as red, brown, and green seaweeds, respectively. Thermal acid hydrolysis, enzymatic saccharification and fermentation were carried out using those seaweeds to produce ethanol. The ethanol concentrations from red, brown and green seaweed were 14.8 g/L, 11.6 g/L and 9.9 g/L, respectively. After the production of ethanol, the seaweeds were reused to absorb heavy metal. The maximum biosorption ratio was Cu(II) (89.6%), Cr(III) (82.9%), Ni(II) (66.1%). Cu(II) had the highest affinity with 3 waste seaweeds. Red seaweed was verified the most effective substrates to both process.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 추계 총회 및 학술발표회
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• pp.61-63
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• 2003

A major research objective related to proton exchange membrane(PEM) for DMFC is to achieve high proton conductivity over 10$^{-2}$ S/cm, high hydrolytic stability and low methanol permeability with low cost base materials. for the purpose, a lot of thermoplastic polymers such as polysulfones, polyethersulfone, polyetherketones, polyimides, polyoxadiazole, polyphosphazene and polybenzimidazol have been investigated. Amongst those polymers, polyimides have been suggested as a potential PEM due to their excellent thermal, chemical stability and good mechanical properties. Generally, polyimides are synthesized by polycondensation with numerious diamines and dianhydriedes. In our study, polyimide was prepared using non-sulfonated diamine, sulfonated diamine directly synthesized by fuming sulfuric acid, and naphthalenic dianhydride to improve the hydrolysis stability under acidic condition. Through monomer sulfonation-subsequent polymerization method, the high proton conducting capability and the desired sulfonation level were effectively controlled at the same time. To reduce severe methanol transport through the membrane, the chemical crosslinking among polymer chains was introduced using various crosslinking agents with different chain lengths. The crosslinked sulfonated polyimide membranes showed high proton conductivity up to 8.09$\times$10$^{-2}$ S/cm and from crosslinking effect methanol transport through the membranes was considerably reduced as compared with unmodified membranes. For increase of chain length of crosslinker, methanol permeability was adversely reduced to 10$^{-8}$ $\textrm{cm}^2$/s due to decrease of IEC and increase of crosslinking desity.

• 한국산림과학회지
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• 제41권1호
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• pp.1-6
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• 1979

1. 본시험(本試驗)은 당화기질(糖化基質)로 산오리나무재(材)를 묽은황산(黃酸)으로 전처리(前處理)한 후(後) Trichoderma viride 16374호균(號菌)에서 얻은 cellulase를 작용(作用)시켜 환원당(還元糖)을 생성(生成)할 수 있는 최적조건(最適條件)을 조사(調査)한 것이다. 즉(卽) 산오리나무(10~15년생(年生))의 톱밥을 전처리(前處理)할 때 황산농도(黃酸濃度) 0.3%, 0.6%, 0.9%, 1.2%, 1.5%로 구분(區分)하고 열압시간(熱壓時間)은 $1.5kg/cm^2$에서 15분(分), 30분(分), 45분(分), 60분(分)으로 각각(各各) 구분(區分) 처리(處理)하여 건조(乾燥)시킨것을 다시 $190^{\circ}C$에서 30분간(分間) 열처리후(熱處理後) 60mesh로 분쇄(粉碎)한 것을 당화기질(糖化基質)로 사용(使用)하였다. 그리고 cellulase 반응조건(反應條件)은 0.1M황산완충액(黃酸緩衝液)(pH 5.0) 50ml, 기질량(基質量) 0.5g, 고근효소액(盬析酵素液) 0.5ml를 100ml용(用) 삼각(三角) flask에 넣고 잘 혼합(混合)한 후(後) $40^{\circ}C$에서 96시간(時間) 반응(反應)시켜 이때 생성(生成)된 환원당량(還元糖量)을 조사(調査)하였다. 2. 고근효소액(盬析酵素液)의 조제(調製)는 밀기울액체진탕배양법(液體振盪培養法)에 의(依에) 하여 생성(生成)된 조효소액(粗酵素液)을 유안절포도(硫安飽和度)에 의(依)한 고근효소액(盬析酵素液)을 만들었다. 3. 환원당정량(還元糖定量)은 DNS법(法)에 의(依)하였다. 4. 묽은황산(黃酸)으로 처리(處理)한 톱밥의 환원당(還元糖) 생성량(生成量)은 황산농도(黃酸濃度) 1.5%, $1.5kg/cm^2$에서 열압시간(熱壓時間)은 45분(分)으로 처리(處理)한 것이 16.0%로 최대량(最大量)을 나타냈으나 작용(作用)함으로서 생성(生成)된 환원당량(還元糖量)은 황산농도(黃酸濃度) 0.9%, 열압시간(熱壓時間) 60분(分) 처리(處理)한 것이 23.6%로(본시험(本試驗) 범위(範圍)에서는 47.5% 증가(增加)) 나타났다.