• Asian-Australasian Journal of Animal Sciences
• /
• v.21 no.1
• /
• pp.97-102
• /
• 2008

Four hundred and forty 1-day-old Arbor Acre broilers were fed commercial starter diets with 0, 250, 750 and 2,250 mg/kg of an alpha-amylase preparation from 1 to 21 days of age to investigate the effects of an exogenous enzyme on growth performance, activities of digestive enzymes in the pancreas and anterior intestinal contents and pancreatic amylase mRNA expression. Body weight gain (BWG) and average daily gain (ADG) increased linearly (p<0.01) with increasing levels of supplementary amylase but feed conversion ratio (FCR) was not affected. There was a negative quadratic change of protease and amylase in the small intestinal contents with the increase of supplementary amylase level. The activity of intestinal trypsin was also increased (p<0.05). Lipase was unaffected by amylase supplementation (p>0.05). The pancreatic protease, trypsin, and lipase were not affected by exogenous amylase levels. Consistent with the tendency for a linear depression of amylase activity, pancreatic ${\alpha}$-amylase mRNA was down-regulated by dietary amylase supplementation. The present study suggested that oral administration of exogenous amylase affected activities of intestinal enzymes and the production of pancreatic digestive enzymes in a dose-dependent manner.

• Applied Chemistry for Engineering
• /
• v.17 no.6
• /
• pp.658-664
• /
• 2006

$\rho$, $\alpha$-dimethyl benzyl alcohol was resolved by the biphasic dynamic kinetic resolution (DKR). Acidic zeolite was used as a racemization catalyst while immobilized enzyme was employed for kinetic resolution. The effects of the process variables including nature of acyl donor, reaction temperature, substrate concentration, ratio of the two catalysts and stirring rate on the conversion and enantiomeric purity of the product were investigated. In DKR of $\rho$, $\alpha$-dimethyl benzyl alcohol, the product of 99% ee was obtained with a maximum yield of 88%. The high performance of the catalyst system was maintained in the condition of higher TON and under repeated use.

• KSBB Journal
• /
• v.5 no.2
• /
• pp.141-149
• /
• 1990

$\beta$-glucosidase derived from Aspergillus niger was immobilized by (1) covalent linkage on chitin and chitosan with glutaraldehyde, (2) adsorption on DEAE-cellulose and Amberite IRA93 after succinylation, and (3) entrapment on alginate and polyacrylamide gels with various cross linking agents. The retention yield of $\beta$-glucosidase immobilized on chitosan was 31.5% and operational stability was 69% after continuous operation at column reactor(5$0^{\circ}C$ at pH 4.8) for 15 days. The retention yield and operational stability were 24.7% and 60% respectively, in adsorption on Amberite IRA 93. On the other hand, the entrapment method by alginate and polyacrylamide gel was identified to be not appropriate due to the continuous elution of inlmobilized $\beta$-glucosidase. Optimum conditions for the immobilization on chitosan were also studied with optimum pH of 4.8 and glutaraldehyde concentration of 0.4%(w/v). The properties and stability of immobilized $\beta$-glucosidase are also investigted. The conversion yield of cellobiose to glucose was also analyzed using the column type enzyme reactor to evaluate the effectiveness of immobilized enzyme.

• Korean Journal of Food Science and Technology
• /
• v.21 no.5
• /
• pp.639-648
• /
• 1989

The possibility of the use of soy sauce koji and commercial proteolytic enzyme for the acceleration of fish fermentation without affecting its characteristic flavor and nutritional quality inherent to the final products was investigated. Fish sauces were prepared experimentally from small horse mackerel under sixteen kinds of conditions and the chemical composition of those were examined, individually. The amino type nitrogen content, ration of amino type nitrogen to total nitrogen and protein conversion ratio were the highest in the fish sauce product treated with soy sauce koji, of which 10% salt was added to the minced raw fish at the start and additional 10% salt was added to the mixture after 48hrs, incubation.

• Journal of Life Science
• /
• v.23 no.11
• /
• pp.1365-1370
• /
• 2013

Immobilized cellulase on weak ion exchange resin showed a typical Langmuir adsorption isotherm. Immobilized cellulase had better stability with respect to pH and temperature than free cellulase. Kinetics of thermal inactivation on free and immobilized cellulase followed first order rate, and immobilized cellulase had a longer half-life than free cellulase. The initial rate method was used to characterize the kinetic parameters of free and immobilized enzyme. The Michaelis-Menten constant $K_m$ was higher for the immobilized enzyme than it was for the free enzyme. The effect of the recirculation rate on cellulose degradation was studied in a recycling packed-bed reactor. In a continuous packed-bed reactor, the increasing flow rate of cellulose decreased the conversion efficiency of cellulose at different input lactose concentrations. Continuous operation for five days was conducted to investigate the stability of long term operation. The retained activity of the immobilized enzymes was 48% after seven days of operation.

• Applied Chemistry for Engineering
• /
• v.23 no.2
• /
• pp.164-168
• /
• 2012

We investigated for the production of biological bio-ethanol from Laminaria japonica using the hydrolysis reaction of enzymes and organic acids and the polysaccharide content was also analyzed. The composition of the polysaccharide was characterized as 65.99% alginate, 6.24% laminaran and 27.77% mannitol. The optimum concentration for reducing the sugar conversion by Laminaria japonica was found to be 1.874 g/L at an acetic acid concentration of 1.5%, $121^{\circ}C$ for 60 min, and for an ascorbic acid of 2.0%, 4.291 g/L was produced in the same condition. The enzyme hydrolysis such as alginate lyase and laminarinase contained the maximum 2.219 g/L reducing sugar. In the result of ethanol fermentation using hydrolysate of Laminaria japonica, the organic acid treatment showed a high of reducing sugar yield, but decreased the ethanol yield, and then the maximum ethanol production obtained was 1.26 g/L using the mixed treated of enzyme.

• Microbiology and Biotechnology Letters
• /
• v.48 no.4
• /
• pp.491-505
• /
• 2020

A newly isolated strain, Proteus vulgaris OR34, from olive mill waste was found to secrete an alkaline extracellular lipase at 11 U·ml-1 when cultivated on an optimized liquid medium. This lipase was purified 94.64-fold with a total yield of 9.11% and its maximal specific activity was shown to be 3232.58 and 1777.92 U·mg-1 when evaluated using the pH-stat technique at 55℃ and pH 9 and Tributyrin TC4 or olive oil as the substrate. The molecular mass of the pure OR34 lipase was estimated to be around 31 kDa, as revealed by SDS-PAGE and its substrate specificity was investigated using a variety of triglycerides. This assay revealed that OR34 lipase preferred short and medium chain fatty acids. In addition, this lipase was stable in the presence of high concentrations of bile salt (NaDC) and calcium ions appear not to be necessary for its activity. This lipase was inhibited by THL (Orlistat) which confirmed its identity as a serine enzyme. In addition, the immobilization of OR34 lipase by adsorption onto calcium carbonate increased its stability at higher temperatures and within a larger pH range. The immobilized lipase exhibited a high tolerance to organic solvents and retained 60% of its activity after 10 months of storage at 4℃. Finally, the OR34 lipase was applied in biodiesel synthesis via oleic acid mediated esterification of methanol when using hexane as solvent. The best conversion yield (67%) was obtained at 12 h and 40℃ using the immobilized enzyme and this enzyme could be reused for six cycles with the same efficiency.

• Microbiology and Biotechnology Letters
• /
• v.37 no.2
• /
• pp.118-124
• /
• 2009

Esterase EM2L8 gene isolated from deep sea sediment was expressed in Escherichia coli BL21 (DE3) and the esterase activity of the cell-free extract was assayed using p-nitrophenyl butyrate-spectrophotometric method. Its optimum temperature was $40-45^{\circ}C$ and 45% activity of the maximum activity was retained at $15^{\circ}C$. The activation energy at $15-45^{\circ}C$ was calculated to be 4.9 kcal/mol showing that esterase EM2L8 was a typical cold-adapted enzyme. Enzyme activity was maintained for 6 h and 4 weeks at $30^{\circ}C$ and $4^{\circ}C$, respectively. When each ethanol, methanol, and acetone was added to the reaction mixture to 15% concentration, enzyme activity was maintained. In the case of DMSO, enzyme activity was kept up to 40% concentration. (S)-4-Chloro-3-hydroxy butyric acid is a chiral intermediate for the synthesis of Atorvastatin, a hyperlipemia drug. When esterase EM2L8 (40 U) was added to buffer solution (1.2 mL, pH 9.0) containing ethyl-(R,S)-4-chloro-3-hydroxybutyrate (38 mM), it was hydrolyzed into 4-chloro-3-hydroxy butyric acid with a rate of $6.8\;{\mu}mole/h$. The enzyme hydrolyzed (S)-substrate more rapidly than (R)-substrate. When conversion yield was 80%, e.e.s value was 40%. When DMSO was added, hydrolysis rate increased to $10.4\;{\mu}mole/h$. The plots of conversion yield vs e.e.s in the presence or absence of DMSO were almost same, implying that the reaction enantioselectivity was not changed by the addition of DMSO. Taken together, esterase EM2L8 had high activity and stability at low temperatures as well as in various organic solvents/aqueous solutions. These properties suggested that it could be used as a biocatalyst in the synthesis of useful pharmaceuticals.

• Microbiology and Biotechnology Letters
• /
• v.26 no.4
• /
• pp.323-330
• /
• 1998

Cyclodextrin glucanotransferase (CGTase) was purified from the culture broth of the Bacillus firmus var. alkalophilus, using ultrafiltration, starch adsorption/desorption, ion-exchange chromatography on DEAE-cellulose and gel filtration on Sephacryl HR-100. The molecular weight of the purified enzyme was determined as 77,000 by SDS-PAGE. The optimum pH and temperature for the CD synthesis were 6.0 and 5$0^{\circ}C$, respectively. The activity of this enzyme was stably kept at the range of pH 6.0～9.5 and up to 5$0^{\circ}C$. However, in the presence of $Ca^{2+}$, the optimum temperature for CD synthesis was shifted 55~6$0^{\circ}C$ and this enzyme was stable up to 6$0^{\circ}C$ because of the stabilizing effect of $Ca^{2+}$. The purified CGTase produced CDs with high conversion yields of 45~51% from sweet potato starch, com starch and amylopectin as substrate, especially, and the product ratio of $\beta$-CD to ${\gamma}$-CD was obtained at range of from 5.8:1 to 8.4:1 according to the kind of substrate. The purified enzyme produced mainly $\beta$-CD without accumulation of $\alpha$-CD during enzyme reaction using various starches as the substrate, indicating that the purified enzyme is the typical $\beta$-CGTase. The purified CGTase produced 25 g/l of CDs from 5.0% (w/v) liquefied com starch and the conversion yield of CDs was 50%, and the content of $\beta$-CD was 84% of total CDs after 8 hours under the optimum reaction condition.ion.

• Applied Biological Chemistry
• /
• v.51 no.3
• /
• pp.177-182
• /
• 2008

This study was carried out to investigate the reaction of lipase-catalyst transesterification using animal fat recovered from fleshing scrap generated during leather making process. Transesterification reaction between fat and primary or secondary alcohol was carried out under the condition of immobilized enzyme catalyst. The conversion rate was the highest when 1.5 mole of methanol was injected by 4 times. As for lipase, Candida antarctica showed the highest conversion rate of 82.2% among the 4 different lipases. It was found that water contained in the fat causes lower conversion rate. The condition of 1.2wt. % of water in the fat decreased the conversion rate by 40%. It was considered that the resulted reactant, fatty acid ester could be used as raw material for biodiesel with the characteristics of not generating SOx and diminishing smoke.