• Fisheries and Aquatic Sciences
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• v.5 no.1
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• pp.21-27
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• 2002

Angiotensin I converting enzyme inhibitory activities of shelled krill (Euphausia superba) hydrolysates by autolysis and by hydrolysis with commercial proteases were analyzed. Among the proteases, Alcalase was the most effective protease for the hydrolysis of krill considering the degree of hydrolysis $(87.5\%)$ and the ACE inhibitory activity $(60\%)$. Four hour hydrolysis suggested as the most suitable and economic. In order to establish the optimum hydrolysis condition of krill, degree of hydrolysis and ACE inhibitory activity as affected by Alcalase concentration and water amount added were statistically analyzed by response surface methodology (RSM). The optimum hydrolysis condition was $2.0\%$ Alcalase hydrolysis in 2 volumes (v/w) of water at $55\% for 4 hr. The hydrolysate prepared from the optimum hydrolysis condition was fractionated by molecular weight. The lower molecular weight fraction showed the higher ACE inhibitory activity. $IC_{50}$ of the fraction under 500 Da was 0.57mg protein/mL.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.4
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• pp.67-75
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• 2011

Sulfuric acid hydrolysis is a typical approach for producing cellulose nanocrystals. The method has been widely used, but it has a disadvantage of low yield of cellulose nanocrystals compared to mechanical method. To expand the application of cellulose nanocrystals in practical, we should be able to produce them with higher yield and the controlled properties. In this study, therefore, we intended to investigate the effect of sulfuric acid hydrolysis condition on the characteristics of the prepared cellulose nanocrystals. The concentration of sulfuric acid, temperature and hydrolysis time were varied, and the yield as well as diverse properties including the morphology, size and zeta potential were examined. We could obtain cellulose nanocrystals up to 70% of yield and found that the properties were dependent on the reaction condition. It would be helpful to select an appropriate condition for producing cellulose nanocrystals.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.606-614
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• 2017

Amount of food waste has been increased annually in Korea and re-use of food waste as a fertilizer or soil amendment in agricultural field has been studied. Therefore, main purpose of this research was to determine optimum condition of hydrolysis for food waste management. Three different solvents, HCl, $H_2SO_4$, and KOH, were used and varied concentration at the range of 10~30% and hydrolysis time at the range of 1~3 hours were evaluated. In general, reduction rate of food waste was increased when concentration of solvent and hydrolysis time was increased except when KOH was used. Among different solvents, concentration, and hydrolysis time, the highest reduction rate (97.79%) was observed when 30% of HCl was used with temperature of $140^{\circ}C$ at 2 hours of hydrolysis time. In addition, neutralization effect of alkalic materials, shell waste (SW) and egg shell (ES) was evaluated. Both SW and ES increased pH of finished acid hydrolysis solution up to 7.61 indicating that neutralization effect of SW and ES was sufficient for finished acid hydrolysis solution. Contents of organic matter was also at the range of 10.7~13.04% and 5.53~8.04% respectively when HCl and $H_2SO_4$ were used as solvent. Overall, hydrolysis technique can be used to manage food waste with selected optimum condition in this study and characteristics of finished hydrolysis solution after neutralization might be suitable for soil amendments.

• Food Science and Preservation
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• v.17 no.2
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• pp.261-266
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• 2010

Acidic hydrolysis conditions prior to HPLC analysis of plant flavonoids was investigated by response surface methodology (RSM), using leaves of Ginkgo biloba L. Ten hydrolysis conditions using 0.5-2.5 M HCl and 0.5-2.5 hr hydrolysis time were chosen to form a central composite rotatable design (CCRD), and optimization by RSM was achieved by measuring myricetin, quercetin, and kaempferol levels by HPLC. Optimum hydrolysis condition was 1.5 M HCl for 1.5 hr. The levels of flavonoids obtained under the condition were in good agreement with predicted maximum values, with yields of more than 95%. These optimum hydrolysis condition was applied to analysis of flavonoid content in the leaves of Camellia sinensis, Ficus carica, and Sageretia theezans.

• Journal of Microbiology
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• v.37 no.2
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• pp.59-65
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• 1999

RecA protein can promote strand assimilation, homologous pairing, and strand exchange. All these reactions require DNA-dependent ATP hydrolysis by recA protein, and the activities of recA protein are affected by the ionic environment. In this experiment, DNA-dependent ATPase activity showed different sensitivity to anionic species. ATP hydrolysis and strand exchange were relatively sensitive to salt in the reactions with NaCl, strongly inhibited at 100 mM NaCl. However, the inhibition by sodium acetate or sodium glutamate was not observed at 50∼100 mM concentration. Addition of sodium glutamate to the standard reaction condition increased the apparent efficiency of ATP hydrolysis during strand exchange. The condition including 50∼100 mM sodium-glutamate might be similar to the physiological condition.

• Journal of the Korean Wood Science and Technology
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• v.43 no.5
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• pp.672-681
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• 2015

As a part of abating the formaldehyde emission of amino resin-bonded wood-based composite panels, this study was conducted to investigate hydrolytic stability of urea-melamine-formaldehyde (UMF) resin depending on various hydrolysis conditions and hardener types. Commercial UMF resin was cured and ground into a powdered form, and then hydrolyzed with hydrochloric acid. After the acid hydrolysis, the concentration of liberated formaldehyde in the hydrolyzed solution and mass loss of the cured UMF resins were determined to compare their hydrolytic stability. The hydrolysis of cured UMF resin increased with an increase in the acid concentration, time, and temperature and with a decrease in the smaller particle size. An optimum hydrolysis condition for the cured UMF resins was determined as $50^{\circ}C$, 90 minutes, 1.0 M hydrochloric acid and $250{\mu}m$ particle size. Hydrolysis of the UMF resin cured with different hardener types showed different degrees of the hydrolytic stability of cured UMF resins with a descending order of aluminum sulfate, ammonium chloride, and ammonium sulfate. The hydrolytic stability also decreased as the addition level of ammonium chloride increased. These results indicated that hardener types and level also had an impact on the hydrolytic stability of cured UMF resins.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.519-526
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• 2005

Hydrolysis of soda-lime waste glass was investigated to test the feasibility for use of waste glass as feed material in the production of foamed glass. The soda-lime glass, such as plate glass and various bottle glasses, was effectively hydrolyzed by steam and water under high pressure. The proper condition for the hydrolysis was found to be reaction temperature of $250^{\circ}C$ and reaction time of 2 h. Under this condition, the water content of hydrated glass through hydrolysis was 7.85~10.04%, allowing successful foaming process for production of foamed glass. Using Na as the modifying agent of glass was effective in the hydrolysis by water. The highest water content of hydrated glass was obtained when weight ratio of NaOH to the glass was 0.04.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.773-777
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• 1999

Scale-up experiments for hydrolysis of beef tallow, fat, and palm kernel with lipase derived from Candida cylindracea were carried out in 1-1, 100-1, and 10,000-1 reactors. The optimum agitation speed for the hydrolysis of the 1-1 reactor was investigated and found to be 350rpm, and this was a basis for the scale-up of agitation speed. The hydrolysis system in this work was the oil-water system in which the hydrolysis seems to process a heterogeneous reaction. An emulsion condition was the most important factor for determining the reaction rate of hydrolysis. Therefore, the scale-up of agitation speed was performed by using the power n = 1/3 in an equation of the rules of thumb method. The geometrical similarity for scaling-up turned out to be unsatisfactory in this study. Thus, the working volume per one agitator was used for the scale-up. In the case of scale-up from a 1-1 reactor to a 100-1 reactor, the hydrolysis of palm kernel was very much scaled-up by initiating the rules of thumb method. However, the hydrolysis of fat and beef tallow in a 100-1 reactor was a little higher than that of the 1-1 reactor because of the difference of geometrical similarity. The scale-up of hydrolysis from the 100-1 reactor to the 10,000-1 reactor was improved compared to that of the 1-1 to 100-1 reactor. The present results indicated that the scale-up of hydrolysis in the oil-water system by the rules of thumb method was more satisfactory under the condition of geometrical similarity. Even in the case where geometrical similarity was not satisfactory, the working volume per one agitator could be used for the scale-up of a heterogeneous enzyme reaction.

• Journal of the Korean Ceramic Society
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• v.28 no.2
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• pp.167-175
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• 1991

In synthesizing hydrated zirconia powder by hydrolysis of Zr-alkoxides using ethanol as mutual solvent, three experimental parameters, namely, concentration of alkoxides and hydrolysis water and addition rate of hydrolysis water were varied systematically. Spherical, monodispersed, nonagglomerated and submicrometer sized powders were prepared at 0.3 M of Zr(n-OPr)4 and 0.05M of Zr(n-OBu)4 with wide ranges of hydrolysis water conditions i.e. 0.5-2.0M concentration and 1-20ml/min addition rate. During the hydrolsis, careful attention have to be paid to maintain homogeneous reaction by controlling the agitation of the reactant and the addition of the hydrolysis water. For more improved condition of monodispersity it was found that the key point is to shorten the self-nucleation time within several seconds as rapid as possible. In both alkoxides system, with higher concentration of alkoxide and hydrolysis water and with slow addition rate of hydrolysis water, hydrated zirconia powders synthesized showed tendency to fall in worse powder conditions.

• KSBB Journal
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• v.30 no.2
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• pp.53-57
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• 2015

In this study, the production of total reducing sugar from macro green-algae Enteromorpha intestinalis by enzymatic hydrolysis was investigated. As a result of enzymatic hydrolysis using 13 kind commercial enzymes, the highest yield of 8.75% was obtained from Viscozyme L, which is multi-enzyme complex such as cellulase, arabanase, beta-glucanase, hemicellulase and xylanase. As a control, only 0.33% and 0.27% yield were obtained from 1% sulfuric acid and 0.05 M citrate buffer (pH 4.8), respectively. In the case of enzyme mixture, the mixture of $Viscozyme^{(R)}$ L and $Cellic^{(R)}$ CTec2 (1:1) was presented the highest yield of 10.67%. Finally, the 14.99% yield was obtained at 36 hr under the condition of 10% biomass and 30% enzyme mixture.