• Journal of Microbiology and Biotechnology
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• 제6권5호
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• pp.336-339
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• 1996

Glutaryl 7-aminocephalosporanic acid acylase of Pseudomonas sp. SY-77-1 was immobilized with oxiran acrylic beads for the production of 7-aminocephalosporanic acid (7-ACA) from glutaryl 7-aminocephalosporanic acid (GL 7-ACA). The immobilized enzyme maintained its activity at a constant level for 7 days, but lost 30$%$ of its activity after 20 days. Optimal reaction conditions for the synthesis of 7-ACA were found to be $30^{\circ}C$ and pH 8.0 using the immobilized enzyme. For the economic production of 7-ACA, substrate and enzyme concentrations were optimized to 60 mM and 0.5 g wet weight per 10 $m\ell$ of reaction volume, respectively. Under optimized conditions, 50 mM 7-ACA was produced from 60mM GL 7-ACA within 8 h, resulting in a conversion yield of 83$%$.

• KSBB Journal
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• 제26권4호
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• pp.347-351
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• 2011

In this study, we investigated the effect of reaction factors on enzymatic hydrolysis of Hizikia fusiforme, which is brown algae in marine biomass resource, using commercial enzymes. The composition of H. fusiforme is 38.9% of reducing sugar, 4.8% of moisture, 17.8% of ash, and 38.5% of others. In the condition of 1-5% substrate, the increase of substrate concentration enhanced the increase of reducing sugar formation; however, the hydrolysis yield did not increase after 24 h. After reaction of 75 h, conversion yield of reducing sugar were obtained to 16.45%, 17.99%, and 14.55% at 1, 2.5, and 5% substrate, respectively. As a result of effect of enzyme amount, the formation of reducing sugar did not show considerable change at 1% substrate. However, in the condition of 2.5% substrate, the great change of reducing sugar formation was observed by the increase of enzyme amount. The conversion yields of reducing sugar were obtained to 18.77% and 22.83% at 1% and 2.5% substrate with 30% enzyme, respectively. As a result of heat treatment of biomass, the high yield was obtained in 2.5% substrate and the yields were increased to 0.06-7.2% by the heat treatment. This result will provide the basic information for production process of biofuels and chemicals from marine biomass H. fusiforme.

• 한국미생물·생명공학회지
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• 제47권4호
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• pp.555-564
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• 2019

Biodiesel is produced through the transesterification process in the presence of alcohol and a catalyst that catalyzes the conversion of triglycerides to esters and glycerol compounds. A more optimal product conversion can be achieved using enzymes, such as lipase. Lipase is reported to be produced in osmophilic yeasts due to the low water content in their natural habitats. Wild forest honey is one of the osmophilic natural habitats in Indonesia. However, lipase-producing yeast has not been reported in the Indonesian honey. In this study, we screened the lipase-producing yeasts isolated from wild forest honey collected from Central Sulawesi. The production profile and activity of lipase were determined at different pH values and temperatures. One promising yeast was isolated from the honey, which was identified as Zygosaccharomyces mellis SG 1.2 based on ITS sequence. The maximum lipase production (24.56 ± 1.30 U/mg biomass) was achieved by culturing the strain in a medium containing 2% olive oil as a carbon source at pH 7 and 30℃ for 40 h. The optimum pH and temperature for lipase activity were 6 and 55℃, respectively. The enzyme maintained 80% of its activity upon incubation at 25℃ for 4 h. However, the enzyme activity decreased by more than 50% upon incubation at 35 and 40℃ for 2 h. This is the first study to report the lipase producing capability of Z. mellis. Further studies are needed to optimize the enzyme production.

• Korean Chemical Engineering Research
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• 제57권4호
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• pp.501-506
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• 2019

New technology-driven biocatalysts are revolutionizing the biochemical industries. With maximum utilization of renewable feedstock, biocatalysts have been the basis for a major breakthrough. Lipases are the most widely established catalysts used for hydrolysis, esterification and transesterification reactions. In this research, a biochemical process that combines extraction of lipase enzyme from germinated wheat seeds and its application to valorize glycerol to acetins by esterification is presented. Acetins are among highly rated, value-added products derived from glycerol. The favorable conditions for the enzymatic conversion of glycerol were observed as glycerol to acetic acid molar ratio (1:5), reaction temperature ($40^{\circ}C$) and the amount of enzyme (20% v/v). 65.93% of glycerol conversion was achieved for duration of 15 h with the use of tert-butanol solvent. This method proposes to explore the viability of a biological route to convert glycerol derived from biodiesel industry to acetins with further streamlining.

• Asian-Australasian Journal of Animal Sciences
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• 제21권7호
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• pp.1053-1058
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• 2008

A total of 392 twenty eight week-old laying hens was used to study the effects of dietary inclusion of solvent-extracted palm kernel cake (PKC) (0%, 12.5% and 25%) and enzyme (mixture of mannanase, ${\alpha}$-galactosidase and protease) supplementation (0 kg/t, 1 kg/t and 2 kg/t) on the performance of laying hens. The levels of PKC did not significantly influence nitrogen corrected true metabolizable energy (TMEn) of the diets. Enzyme-supplemented PKC had significantly higher AME and TMEn values than PKC diets with no enzyme supplementation. Dietary inclusion of 12.5% and 25% PKC in the diets of laying hens did not adversely affect mean egg production or daily egg mass. However, layers consumed significantly more PKC-based diets and had significantly poorer feed conversion ratios (FCR) than controls. However, the feed intake and FCR of hens provided the 12.5% PKC-based diets with enzyme supplementation at 1 kg/t did not differ from the controls. Dietary inclusion of PKC or enzyme did not affect eggshell quality, but egg yolk colour was significantly paler when layers were fed the 25% PKC diet.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.567-570
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• 2000

DFA IV를 생산하는 levan fructotransferase를 ${\kappa}\;-carrageenan$을 이용하여 고정화한 결과 카라기난의 농도가 2%일 때 가장 높은 활성을 나타내었다. 이 때에 고정화 담체에 포괄되어지는 효소의 활성도는 0.81 units으로서 soluble enzyme 7.7 units에 비해 상대적으로 낮은 활성을 보여주었다. 고정화 및 soluble enzyme의 최고 활성온도와 최적 pH는 동일하게 $55^{\circ}C$, pH6.0 이었다. 가교제를 처리할 경우에 적당한 농도는 0.5%로 생각되어진다. $37^{\circ}C$에서 시간에 따른 고정화 및 soluble enzyme의 DFA IV 생산량을 HPLC로 분석한 결과 60시간 이후의 전환률이 각각 32%, 61%로 나타났다.

• 약학회지
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• 제21권3호
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• pp.167-171
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• 1977

A new assay method for delta-l-dehydrogenated-3-ketoco-rticosteroid in the presence of proteinous material or whole-cell-enzyme and 3-ketocorticosteroid has been developed. This method makes use of the linear relationship between the ratio of absorbances at 265 nm and at 242 nm and the fractional concentration of delta-1-3-ketosteroid. Theoretical values were calculated based on the absorbances of proteinous material at fixed concentrations of the 3-ketosteroid and delta-1-dehydrogenated-3-ketosteroid. The values obtained experimentally showed good agreement with the values obtained experimentally showed good agreement with the values theoretically predicted. The new assay method developed for the steroid mixtiure containing proteinous material is of some practical importance. The use of such assay method enables one to determine the enzyme activity and the rate of enzyme reaction or conversion rather quickly, easily and accurately. By the use of this assay method, the reaction kinetics of whole-cell-enzyme has also been studied. It was found that it followed the simple Michaelis-Menten type enzyme kinetics. Also the reversibility of this reaction with actively metabolizing cell was examined. It was found that delta-l-dehydrogenated-3-ketosteroid could not be hydrogenated reversibly to 3-ketosteroid by this enzyme system.

• 생명과학회지
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• 제8권3호
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• pp.326-332
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• 1998

Cyclodextrin glucanotransferase from B. stearothermophilus KJ16 that can produce both cyclodextrin glucanotransferase and cyclodextrinase was purified by ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-100 chromatography, and FPLC. The molecular weight of the purifice enzyme was about 65,000 dalton by SDS-PAGE. The optimal pH and temperature were 6.0 and $60^{\circ}C$, respectively. The enzyme was stable at $50^{\circ}C$ for 1 hr and in the pH range of 5.5 and 8.5. Mercaptoethanol and dithiothreitol inhibited the enzyme activity strongly. The enzyme produced 60% cyclodextrin(CD) from 5% soluble starch with the $^{\alpha}$, $^{\beta}$, $^{\gamma}$-CD ratio of 42:46:12. Amylopectin was the most suitable substrate with 67% conversion to CD.

• Toxicological Research
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• 제22권1호
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• pp.39-45
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• 2006

As the antioxidant and free radical scavenger, glutathione (GSH) participates in the preservation of cellular redox status and defense against reactive oxygen species and xenobiotics. Glutamate-cysteine ligase (GCL; also known as ${\gamma}$-glutamylcysteine synthetase, EC 6.3.2.2) is the rate limiting enzyme in GSH synthesis. In the present study, the accurate method for determination of GCL activity in crude liver extracts was developed by measuring both ${\gamma}$-glutamylcysteine and GSH from cysteine in the presence of glutamate, glycine and an ATP-generating system. We added glycine to promote the conversion of ${\gamma}$-glutamylcysteine to GSH, and to minimize the possibility of ${\gamma}$-glutamylcysteine metabolism to cysteine and oxoproline by ${\gamma}$-glutamylcyclotransferase. We established optimal conditions and substrate concentrations for the enzyme assay, and verified that inhibition of GCL by GSH did not interfere with this assay. Therefore, this assay of hepatic GCL under optimal conditions could provide a more accurate measurement of this enzyme activity in the crude liver extracts.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 1978년도 추계학술대회
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• pp.206.4-206
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• 1978

By utilizillg whole cell enzyme of the Xantho-monas citri IFO 3835, cephalexin is synthesized directly from 7-amino-deacetoxy cephalosporanic acid (7-ADCA) and phenyl glycine methyl ester (PGM). To date, cephalexin has been manufactu-red by chemical process involving fairly large number of steps to protect the amino group of phenly glycine and carboxyl group of 7-ADCA. However, the enzymatic process involves only a single step with 85％ conversion in 90 minutes. The fermentation variables studied indicate that oxygen transfer is limiting step in the enzyme production. Optimum conditions for enzymatic reaction were 37 C, pH 6.0, and the optimum substrate molar ratio of PGM to 7-ADCA was 2. Other variables that are related to the biochemical properties of whole cell enzyme temperature stability, pH stability, kinetic constants, reusing effect, enzyme loading effect were also evaluated.