• Applied Biological Chemistry
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• v.34 no.1
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• pp.1-7
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• 1991

Optimum conditions for hydrolysis of sunflower seed by pepsin and for plastein formation by pepsin were determined. The optimum conditions for hydrolysis of sunflower seed were pH 1.5, $45^{\circ}C$, enzyme concentration 2%, substrate concentration 2%, and hydrolysis time 24hr. The optimum conditions for sunflower seed-plastein formation were 50% substrate, pH 4.5, $50^{\circ}C$, 0.25% pepsin and 18hrs reaction time. To verify plastein fromation from concentrated prptic hydrolysate of sunflower seed, thin layer chromatography was performed. The TLC pattern of concentrated peptic hydrolysate of sunflower seed was different from that of its plastein. The TLC pattern of concentrated peptic bydrolysate of sunflower seed and at of its plastein indicated that plastein was different material from the hydrolysate.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.15-24
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• 2010

Coagulation can be used for pretreatment of NF membrane filtration. Foulants such as organic matter and particulate can be removed effectively with the process while high flux recovery is maintained. Recently various types of polyaluminium coagulants including polyaluminium chloride(PAC) are commercially available for water treatment. This study examines effects of polymeric Al and hydrolysis products of PAC on nanofiltration membrane performance. Dominant hydrolysis products were polymeric Al, $Al(OH)_3$, and ${Al(OH)_4}^{-1}$ at acidic, neutral, and alkaline pH conditions, respectively. Under acidic pH condition, flux decline was increased with increasing PAC concentrations, possibly due to polymeric Al adsorption on membrane pore and/or surfaces. For neutral and alkaline pH conditions, little flux decline was observed with increasing PAC concentrations except the highest ${Al(OH)_4}^{-1}$ concentration, with which rapid flux decline was shown. Removal of ionic matters was also varied with pH conditions in this study. Especially, conductivity removal was substantially low and $Ca^{2+}$ concentration in the permeate was quite high at neutral pH condition.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.1
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• pp.48-52
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• 2011

The effect of soil water content on the transformation potential of N compounds derived from hydrolysis of urea applied in a reclaimed tidal soils which was saline-sodic was observed to evaluate nitrification rates of urea. Soil samples were collected from Moonpo series at the newly reclaimed area in Saemanguem. For the transformation potential of N compounds from urea (46% N), newly reclaimed tidal soils (RS) were amended with urea at the rates of 0, 10, and 20 kg $10a^{-1}$. With leachate obtained from the incubated RS in a leaching tube at $25^{\circ}C$, urea hydrolysis and nitrification were measured for a total of 30days. The cumulative amounts of $NO_3{^-}$-N in each of the four soils treated with urea was linear with time of incubation. Results showed that increase in pH occurred with increasing application rate of urea and volumetric water content due to hydrolysis of urea. The total N in the RS was decreased with incubation time, indicating that rates of urea hydrolysis was influenced by soil moisture conditions. Also, the cumulative amount of nitrate in RS gradually increased with increase in time of incubation.

• KSBB Journal
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• v.4 no.2
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• pp.78-86
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• 1989

The effective saccharification of cellulosic biomass to glucose is the most critical step for the conversion of renwable biomass to alternative liquid fuel. The enzymatic hydrolysis of biomass can be significantly enhanced provide the attrition milling media is added during hydrolysis. The enhancing mechanism of hydrolysis reaction in an agitated bead system was investigated. An attrition-reactor (bioattritor) which installed specially designed torque measuring apparatus was developed, and the potimal saccharification conditions of bioattritor were determined. The relationship between the power consumption required for agitation of attrition-milling media and enhanced extent of hydrolysis of biomass was compared to evaluatic economic feasibility of the process.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.197-203
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• 1992

Studies of the pretreatment of chitin and its subsequent hydrolysis by Aspergillus carneus chitinase are reported. Ball milling was found to be the most effective way among the pretreatment methods tested. Data are presented describing the effect of enzyme and substrate concentrations on the rate and extent of the hydrolysis process. It was found that the successive addition of enzyme improved the saccharification yield. Significant product inhibition of the chitinase was observed when N-acetylglucosamine concentration was 3.6％ or higher. Adsorption of enzymes to the substrate occurred during a 24 hr hydrolysis period. An initial rapid and extensive adsorption occurred, followed by gradual desorption which increased during the time of reaction. Intermediate removal of the hydrolyzate and continuation of the hydrolysis by adsorbed enzyme on the residual chitin was also investigated. A total of 75.4 g/l reducing sugars, corresponding to 69.2％ saccharificaton yield (as N-acetylglucosamine) was obtained. In addition an increase in the amount of recoverable enzymes was observed under these conditions. Evidence presented here suggests that the technique, whereby the free enzymes in the recovered hydrolyzate are re-adsorbed onto the new substrate, may provide a means of recirculating the dissolved enzymes.

• Korean Journal of Food Science and Technology
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• v.41 no.6
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• pp.622-627
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• 2009

The objectives of this study were to evaluate a protease suitable for the enzymatic hydrolysis of a snow crab processing by-product (SPB) and to optimize the hydrolysis conditions using response surface methodology (RSM). The SPB was hydrolyzed at $50^{\circ}C$ and pH 7.0-7.2 to obtain various degree of hydrolysis (DH) using Flavourzyme at an enzyme/substrate (E/S) ratio of 3.0%. The reaction progress curve exhibited an initial fast reaction rate followed by a slowing of the rate. The DH was increased to 30% at 90 min with a final DH 32 to 36%. A central composite experimental design having three independent variables (reaction temperature, reaction time, and E/S ratio) with five levels was used to optimize the enzymatic hydrolysis conditions. Based on the DH data, the optimum reaction conditions for the enzymatic hydrolysis of the SPB were a temperature of $51.8^{\circ}C$, reaction time of 4 hr 45 min, and an E/S ratio of 3.8%. It was demonstrated that the enzymatic hydrolysate of SPB could be used as a flavoring agent or a source of precursors for the production of reaction flavors.

• Textile Coloration and Finishing
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• v.6 no.2
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• pp.10-16
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• 1994

Neutral salts have negative or positive effects on the rates of many chemical reactions and also on the rates of acidic and alkaline hydrolysis of carboxylic esters. The direction of neutral salt effects on the hydrolysis of ester depends on the charge of esters. Neutral salts accelerate alkaline hydrolysis of esters with negative charge, but decelerate alkaline hydrolysis of esters with positive charge, and have little effect on the alkaline hydrolysis of neutral esters. It is expected that the rate of the alkaline hydrolysis of Poly(ethylene terephthalte) (PET), polymeric solid carboxylic polyester with carboxyl end group at the polymer end, is also influenced positively by neutral salts. In the present work, to clarify the mechanism of the neutral salt effect on the alkaline hydrolysis of PET, many salts with different anions like NaF, NACl, NaBr, NaI were added to the aqueous alkaline solutions. Then PET was hydrolyzed with aqueous solutions of many salts in alkali metal hydroxides under various conditions. Some conclusions obtained from the experimental results were summarized as follows. The reaction rate of the alkaline hydrolysis of PET was increased by the addition of neutral salts and In k was increased nearly linearly with the square root of ionic strength of reaction medium. This fact suggested that the ionic strength effect by Debye-Huckel and Bronsted theory was exerted on the reaction. The specific salt effect was also observed. The reaction rate was increased with the decrease in the nucleophilicity of anions of neutral salts, i.e., in the order of $F^-$ <$Cl^-$<$Br^-$<$I^-$. It was thought that the reaction rate was increased in the order of $F^-$ <$Cl^-$<$Br^-$<$I^-$. because the completion of anions with $OH^-$ for carbonyl carbon became weaker with the decrease in the nucleophilicity and with the increase in the size of anions.

• Textile Coloration and Finishing
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• v.29 no.4
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• pp.181-194
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• 2017

The biodegradability of polylactic acid(PLA) fabrics was evaluated by two methods: enzyme and soil degradation. Three different enzymes were selected to evaluate. Degradation times were measured at optimal enzyme treatment conditions. Biodegradation by enzymatic hydrolysis was compared with soil degradation. As a result, biodegradation created cracks on the fiber surface, which led to fiber thickening and shortening. In addition, new peak was observed at $18.5^{\circ}$ by degradation. Moreover, cracks indicating biofragmentation were confirmed by enzyme and soil degradation. By enzyme and soil degradation, the weight loss of PLA fabrics was occurred, there through, the tensile strength decreased about 25% by enzyme hydrolysis when 21 days after, and 21.67% by soil degradation when 60 days after. Furthermore, the biodegradability of PLA fabrics by enzymatic and soil degradation was investigated and enzymatic degradation was found to be superior to soil degradation of PLA fabrics. Among the three enzymes evaluated for enzymatic degradation, alcalase was the most efficient enzymes. This study established the mechanism of biodegradation of PLA nonwovens, which might prove useful in the textile industry.

• Textile Coloration and Finishing
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• v.8 no.4
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• pp.25-30
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• 1996

This study was carried out to examine the effect of lipase on the removal of tripalmitin in the various conditions of washing. The relations between the removal and the hydrolysis of tripalmitin by lipase were discussed. The hydrolysis characteristics of lipase were examined by a colorimetric determination of liberated fatty acids as a new assay of lipase in reverse micelies. The hydrolysis of tripalmitin by lipase was increased with the increase of reaction time and reaction above lipase concentration 150mg/l pH at reaction temperature 4$0^{\circ}C$.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3665-3676
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• 2023

The use of ion exchange resins to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system (PHTS) purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain the complex chemistry in ion exchange beds, particularly when operated at or near their saturation limit. This work investigates the behaviour of mixed-bed ion exchange resin, saturated with species representative of corrosion products in a CANDU (Canadian Deuterium Uranium) reactor PHTS, particularly with respect to iron chemistry in the resin bed and the removal of lithium ions from solution. Experiments were performed under deaerated conditions, analogous to normal PHTS operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin bound ferrous species and the subsequent formation of either a solid hydrolysis product or the soluble, anionic Fe(OH)₃^-.