• 한국환경보건학회지
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• 제31권4호
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• pp.294-300
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• 2005

Food waste can be a valuable carbon source in biological nutrient removal (BNR) systems because of high C/N and C/P ratios. However, food waste should be pretreated to promote its hydrolysis rate because hydrolysis reaction would be a rate-limiting step. This study investigates the influence of the enzymatic pretreatment on acid fermentation of food waste. Solubilization of particulate matter in food waste by using commercial enzymes was examined. The acidification efficiency and the volatile fatty acids (VFAs) production potential of enzymatically pretreated food waste were also examined. The highest volatile suspended solids (VSS) reduction was obtained with an enzyme mixture ratio of 1:2:1 of carbohydrase:protease:lipase. An optimum enzyme dosage for solubilization of food waste was $0.1\%$(V/V) with the enzyme mixture ratio of 1:2:1. In the acid fermentation of enzymatically pretreated food waste, $0.1\%$(V/V) enzyme mixture dosage for pretreatment result in the maximum VFAs production and the best VFAs fraction in soluble COD(SCOD). The VFAs production at this addition level was 3.3 times higher than that of no-enzyme added fermenter. The dominant VFAs present was n-butyrate followed by acetate.

• KSBB Journal
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• 제14권4호
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• pp.511-516
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• 1999

유지의 가수분해시, 반응온도, 금속이온, pH, 교반속도, 물-유지의 무게비 및 효소량 등의 환경 및 조성인자가 효소 Lipase-OF의 역가 및 가수분해특성에 미치는 영향을 규명하였다. 융점이 낮은 유지의 경우 Lipase-OF의 활성이 가장 높은 온도는 37$^{\circ}C$ 근방이었으나 융점이 4$0^{\circ}C$ 이상의 온도 범위에서는 유지의 종류에 관계없이 온도가 상승하면 Lipase-OF의 활성이 급격히 감소하여 $65^{\circ}C$ 이상에서는 효소의 활성이 정지되었다. 교반속도를 150, 250, 350, 450, 550 및 650 rmp으로 변화시켜가면서 유지의 가수분해실험을 수행하여 350 rpm 이하에서는 교반속도가 상승하면 가수분해율도 상승하였으나 교반속도 350 rpm 이상에서는 교반속도 상승에 대한 가수분해율의 변화를 찾아볼 수 없었다. 유지와 물의 무게비를 9 : 1에서 1 : 9까지 변화시켜가면서 가수분해실험을 수행하여 일정한 가수분해 시간에서 가수분해율이 가장 높은 무게비가 1 : 1 근방의 값임을 규명하였다. 금속 이온 중 $Ca^{2+}와\;Mg^{2+}$ 이온이 가수분해율 상승에 기여하였다. 금속이온이 없는 경우에 비하여 $Ca^{2+}$또는 $Mg^{2+}$ 이온 농도가 100 ppm 근방의 값일 때 2 내지 3%의 가수분해율 증가효과를 나타내었다. Lipase-OF에 대한 최적 pH는 7근방이었다. pH가 산성쪽으로 감소하면 가수분해율도 감소하였으며 알칼리쪽으로 증가하여도 가수분해율이 감소하였다. 기질의 0.00075 wt% 와 0.1 wt% 범위내에서 Lipase-OF량이 가수분해율에 미치는 영향을 규명하였다. 효소량 0.013 wt% 이하에서는 효소량이 증가하면 가수분해율도 증가하였으나 0.013 wt% 이상에서는 효소량이 증가하여도 가수분해율은 증가하지 않았다. Lipase-OF의 가수분해율에 미치는 환경 및 조성인자의 영향에 대한 실험을 통하여 최적온도는 37$^{\circ}C$, 최적 pH는 7, $Ca^{2+}\;또는\;Mg^{2+}$의 최적농도는 100 ppm, 최적교반속도는 350 rpm, 유지와 물의 최적무게비는 1 : 1 및 최적 효소량은 유지의 0.013 wt%임을 규명하였다.

• 한국의류학회지
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• 제20권3호
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• pp.550-559
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• 1996

The Effect of protease (subtilisin Carlsberg) on the removal of hemoglobin as protein soil was studied. The hydrolysis characteristics of subtilisin Carlsberg was examined by electrophoretic techniques. The fragmentation patterns of hemoglobin were analyzed by SDS-PAGE. The hydrolysis efficiency was evaluated by analysis of protein bands shown on gels before and after hydrolysis by using densitometer. 1. The hydrolysis of hemoglobin by subtilisin Carlsberg was increased markedly with the increase of the enzyme concentration. 2. The hydrolysis of hemoglobin by subtilisin Carlsberg was effectively increased in proportion to increasing of the hemoglobin concentration up to a certain point, but it began to decrease above the point. 3. The hydrolysis of hemoglobin by subtilisin Carlsberg followed the first order kinetics, yielding a rate constant of $4.05\time10^{-4}S^{-1}s$. 4. The hydrolysis of hemoglobin by subtilisin Carlsberg was highest at $50^{\circ}C$ and was decreased markedly at $80^{\circ}C$. 5. The hydrolysis of hemoglobin was comparatively low at pH 7.0~8.0, and highest at pH 11.0.

• Bulletin of the Korean Chemical Society
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• 제24권1호
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• pp.65-69
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• 2003

The kinetic and chemical mechanisms of AChE-catalyzed hydrolysis of short-chain thiocholine esters are relatively well documented. Up to propanoylthiocholine (PrTCh) the chemical mechanism is general acid-base catalysis by the active site catalytic triad. The chemical mechanism for the enzyme-catalyzed butyrylthiocholine(BuTCh) hydrolysis shifts to a parallel mechanism in which general base catalysis by E199 of direct water attack to the carbonyl carbon of the substrate. [Selwood, T., et al. J. Am. Chem. Soc. 1993, 115, 10477- 10482] The long chain thiocholine esters such as hexanoylthiocholine (HexTCh), heptanoylthiocholine (HepTCh), and octanoylthiocholine (OcTCh) are hydrolyzed by electric eel acetylcholinesterase (AChE). The kinetic parameters are determined to show that these compounds have a lower Michaelis constant than BuTCh and the pH-rate profile showed that the mechanism is similar to that of BuTCh hydrolysis. The solvent isotope effect and proton inventory of AChE-catalyzed hydrolysis of HexTCh showed that one proton transfer is involved in the transition state of the acylation stage. The relationship between the dipole moment and the Michaelis constant of the long chain thiocholine esters showed that the dipole moment is the most important factor for the binding of a substrate to the enzyme active site.

• Journal of Microbiology and Biotechnology
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• 제16권8호
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• pp.1255-1261
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• 2006

An alkaliphilic bacterium, Bacillus sp. strain BK, was found to produce extracellular cellulase-free xylanolytic enzymes with xylan-binding activity. Since the pellet-bound xylanase is eluted with 2% TEA from the pellet of the culture, they contain a xylan-binding region that is stronger than the xylan-binding xylanase of the extracellular enzyme. The xylanases had a different molecular weight and xylan-binding ability. The enzyme activity of xylanase in the extracellular fraction was 6 times higher than in the pellet-bound enzyme. Among the enzymes, xylanase had the highest enzyme activity. When Bacillus sp. strain BK was grown in pH 10.5 alkaline medium containing xylan as the sole carbon source, the bacterium produced xylanase, arabinofuranosidase, acetyl esterase, and $\beta$-xylosidase with specific activities of 1.23, 0.11, 0.06, and 0.04 unit per mg of protein, respectively. However, there was no cellulase activity detected in the crude enzyme preparation. The hydrolysis of agricultural residues and kraft pulps by the xylanolytic enzymes was examined at 50$^{\circ}C$ and pH 7.0. The rate of xylan hydrolysis in com hull was higher than those of sugarcane bagasse, rice straw, com cop, rice husk, and rice bran. In contrast, the rate of xylan hydrolysis in sugarcane pulp was 2.01 and 3.52 times higher than those of eucalyptus and pine pulp, respectively. In conclusion, this enzyme can be used to hydrolyze xylan in agricultural residues and kraft pulps to breach and regenerate paper from recycled environmental resources.

• Journal of Microbiology and Biotechnology
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• 제7권2호
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• pp.151-156
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• 1997

Two commercially available lipases, Lipase OF (non-specific lipase from Candida rugosa) and Lipolase 100T (1, 3-specific lipase from Aspergillus niger), were immobilized on insoluble hydrophobic support HDPE (high density polyethylene) by the physical adsorption method. Hydrolysis performance was enhanced by mixing a non-specific Lipase OF and a 1, 3-specific Lipolase 100T at a 2 : 1 ratio. The results also showed that the immobilized lipase maintained its activity at broader temperature ($25~55^{\circ}C$) and pH (4-8) ranges than soluble lipases. In the presence of organic solvent (isooctane), the immobilized lipase retained most of its activity in upto 12 runs of hydrolysis experiment. However, without organic solvent in the reaction mixture, the immobilized lipase maintained most of its activity even after 20 runs of hydrolysis experiment.

• Archives of Pharmacal Research
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• 제11권4호
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• pp.285-291
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• 1988

2-mercaptoethanol, thioglycolic acid, glutathione, 3-mercapto-1, 2-propanediol and 3-mercapto-2-butanol showed catalytic activities on the hydrolysis of $\alpha$-amino-phenylacetonitrile to phenylglycineamide at the rate of 12.19 $\times$ $10^{-2}$, 8.03 $\times$ $10^[-2}$, 6.83 $\times$ $10^{-2}$, 8.60 $\times$ $10^{-2}$ and 6.04 $\times$ $10^{-2}$ mM $min^{-1}$, respectively. hte hydrolysis rate was faster in buffer than in water. The hydrolysis of the nitrile compound to phenylglycine was limited.

• 한국토양비료학회지
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• 제44권1호
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• pp.84-90
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• 2011

It is imperative to study the hydrolysis of urea in high saline-sodic condition of a newly reclaimed tidal land in order to overcome the problems associated with use of urea fertilizer. The methodology adopted in this study tried to get a convenient way of estimating rate for N transformation needed in N fate and transport studies by reviewing pH and salt contents which can affect the microbial activity which is closely related to the rate of urea hydrolysis. The hydrolysis of urea over time follows first-order kinetics and soil urease activity in reclaimed soils will be represented by Michaelis-Menten-type kinetics. However, high pH and less microorganisms may delay the hydrolysis of urea due to decrease in urease activity with increasing pH. Therefore, the rate of urea hydrolysis should adopt $V_{max}$ referring enzyme activity ($E_0$) accounting for urease concentration which is indicative for urea hydrolysis, especially in a high saline and sodic soils.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2003년도 제39회 학술심포지움
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• pp.130-130
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• 2003

• 한국수산과학회지
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• 제32권2호
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• pp.127-133
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• 1999

참치 자숙액 중에 함유되어 단백질을 효율적으로 이용하고자 막반응기에서 연속적으로 효소적 가수분해를 수행하기 위한 최적 조건을 검토하였다. 회분식에서 TPCCE를 이용한 자숙액의 최적 가수분해조건은 pH 9.0, 반응온도는 $40^{\circ}C$, 기질인 자숙액에 대한 효소비 50(w/w) 및 기질농도 $1\%$ (w/v)였으며, 이 때 6시간의 반응시간에 의해 약$70\%$의 가수분해도를 나타내었다. 그리고 TPCCE를 이용하는 것이 시판 단백질 분해효소보다 효과적이었다. 막반응기에서 자숙액을 연속적으로 효소적 가수분해를 수행하기 위한 막반응기의 작동조건의 검토에서, 기질용액을 pH 9 및 $40^{\circ}C$로 조절한 후 자숙액의 반응시간에 따른 가수분해도는 3시간, $1\%$ (w/v) 자숙액에 대한 효소농도는 0,1 g/$\ell$, 자숙액 대 효소비는 100 (w/w), 그리고 기질농도는 $5\%$ (w/v)였으며, 이 때 가수분해도는 약 $60\%$를 나타내었다.