• Journal of Sericultural and Entomological Science
• /
• v.40 no.2
• /
• pp.131-135
• /
• 1998

Changes of silk fibroin molecular weight was studied by enzymatic proteolysis and reverse reaction of enzymatic proteolysis (plastein reaction) using chromatography, X-ray diffraction and thermal analysis methods. When the treatment of enzymatic proteolysis with $\alpha$-chymotripsin to silk fibroin solution, a precipitate of Fcp fractions was formed. And, this was dissolved in LiBr aqueous solution, the precipitate of PIFcp fractions was obtained again. Fcp and PIFcp fractions showed silk IIand silk Itype structure, respectively. Fcp fractions was about 6,900 in molecular weight, PIFcp fractions obtained by plastein reaction on the precipitate of Fcp fractions increased molecular weight to abort 15,000. The molecular weight of Fcp fractions was increased by plastein reaction, but Fcp fractions almost transited to silk I type crystal. The structure of silk I type of PIFcp fractions was steady identified by X-ray diffraction and thermal analysis. As molecular weight of Fcp fractions was gradually low, PIFcp fractions was become to macromolecule little by little.

• Fisheries and Aquatic Sciences
• /
• v.11 no.2
• /
• pp.71-75
• /
• 2008

The shell of Reeve's turtle has been used as a traditional folk medicine in Korea. We produced a hot water extract from Reeve's turtle shell according to the traditional medical practice. To release bioactive peptides, the hot water extract was enzymatically hydrolyzed with various proteases, and the free radical scavenging activity of the hydrolysate was investigated against 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydroxyl and peroxyl radicals. The free radical scavenging activity of the enzymatic hydrolysates varied from 1 to 79% depending on the enzymes, free radical species, and concentration. The $EC_{50}$ values demonstrated that the enzymatic hydrolysates of hot water extract from the shell of Reeve's turtle are potential antioxidants.

• Macromolecular Research
• /
• v.16 no.7
• /
• pp.651-658
• /
• 2008

Poly(butylene succiate) (PBS), poly(butylene succinate-co-L-lactate) (PBSL), and poly(butylene succinate-co-6-hydroxycaproate) (PBSCL) polymers were degraded by lipase $PS^{(R)}$, and the enzymatic degradation mechanism of PBS was analyzed in detail. The enzymatic degradation of PBS gave 4-hydroxybutyl succinate (4HBS) as the main product. An exo-type hydrolysis mechanism was proposed based on this observation. The terminal chain of PBS had conformational similarity to ordinary tri- and diglycerides and could be incorporated as a substrate in the active site of this lipase. The surface adsorption of the lipase was much larger on PBS and its copolymer films than on the other polyester films because the lipase adhered quite strongly to the polymer terminal through a specific adsorption mechanism. Kinetic analysis showed that the total number of surface adsorption points per unit area of PBSL and PBSCL copolymers was larger than that of the PBS homopolymer.

• YAKHAK HOEJI
• /
• v.4 no.1
• /
• pp.35-38
• /
• 1959

The enzymatic activity of amylase which was isolated from a shell fish Veneridae Soxidmnus purpuratus Sowerby(Korean name :Gai-jo-gai") was studied and the obtained results were as follows: (1) The optimum pH of the enzyme was Ca. 6.2-6.4. (2) Prohibiting activity of metalic ions for the enzymatic activity was the order of 1/1000M-$Mg^{++}$>1/1000M-$Sr^{++}$>1/1000M-$Na^{+}$, and $Ca^{++}$ ion's prohibiting action was hardly showed. (3) Of 3 specimens of amyiase from Heptapancreas, Gastro-intestine and crystalline style, the highest activity was shown by amylase from crystlline style, and the other two showed almost same degree of activity. (4) Heptapancreas Amylase from the shell fish showed remarkably higher enzymatic activity than the pancreas amylase from a pig.

• Journal of Sericultural and Entomological Science
• /
• v.41 no.3
• /
• pp.211-215
• /
• 1999

The pure-separation of calcium chloride-treated fibroin hydrolysates could be carried out using gel filtration chromatography. Also, the effect of its enzymatic hydrolysis was investigated in order to find out the enhancement of their functionality. The average molecular weight(Mw), solubility and free amino acid compositions of three hydrolysates samples (calcium chloride, calcium chloride-flavourzyme and calcium chloride-thermoase)were measured to compare their characteristics. The molecular weight of calcium chloride hydrolysate was about Mw 46,800 and it can be reduced to Mw 12,500 and 1,070 upon the enzymatic hydrolysis by flavourzyme and thermoase, repectively. A solubility of calcium chloride-treated samples shows about 60% while calcium chloride/enzyme-treated samples are perfectly soluble (100% solubility). The total amino acid composition of calcium chloride enzymatic hydrolysates are much higher than that of calcium chloride hydrolysate.

• Current Research on Agriculture and Life Sciences
• /
• v.22
• /
• pp.49-56
• /
• 2004

Cellulolytic enzymes were prepared from alkaline resistant microorganisms which were newly screened from calcic soil. Characteristics of enzymes and enzymatic deinking efficiency of wastepaper were investigated. The results were summarized as fellows: 1. The recovery rate of crude enzyme was 93.7% in Bio-B and 57.4% in Bio-F. 2. The protein content in crude enzymes was lowest and the thermal stability of crude enzymes was highest in Bio-F. 3. The brightness gain of Bio-F deinked pulp was best in ONP and Bio-B deinked pulp was best in MOW. 4. The reject yield was increased with enzymatic deinking flotation process. 5. The residual ink area of paper was increased with enzymatic deinking and large size of ink particles were remained in paper.

• Korean Journal of Plant Resources
• /
• v.21 no.3
• /
• pp.222-225
• /
• 2008

Chemical composition and enzymatic saccharification characteristics of hemp woody core were investigated by their chemical composition analysis and enzymatic saccharification with commercially available cellulases (Celluclast 1.5L and Novozym 342). Hemp woody core have higher xylan and lower lignin contents than its bast fiber. Based on hemicelluloses and lignin composition, hemp woody core is similar with hardwood biomass. However, cellulose was more easily converted to glucose than xylan to xylose and this trend was confirmed both hemp woody core and yellow poplar. Hemp woody core biomass shows higher saccharification than yellow poplar (hardwood biomass) based on cellulose and xylan hydrolysis. With easier enzymatic saccharification in cellulose and xylan, and similar chemical composition, hemp woody core have better biorefinery feedstock characteristics than hardwood biomass.

• Food Science and Industry
• /
• v.51 no.2
• /
• pp.100-113
• /
• 2018

To obtain an edible grade oil from crude oil extracted from oil-bearing materials, it is generally necessary to carry out a refining process composed with degumming, deacidification, bleaching, and deodorization, to remove undesirable matters which affect the quality and shelf life of oils. The main purpose of degumming is to remove gum material mainly consisted with phospholipids. Phospholipases convert nonhydratable phospholipids into their hydratable forms which can be removed by centrifugation. In comparison with conventional water and acid degumming processes, enzymatic degumming can result the lower phosphatide content in oil than conventional processes. The enzymatic degumming can be conducted with the reduced amount of acid, and contributes to generate less amount of wastewater, decrease of operating cost, and increase oil recovery yield. The phospholipases used in enzymatic degumming process are phospholipase A1, A2, B, and C.

• Journal of Forest and Environmental Science
• /
• v.26 no.2
• /
• pp.137-148
• /
• 2010

The high costs for ethanol production with lignocellulosic biomass as a second generation energy materials currently deter commercialization of lignocellulosic biomass, especially wood biomass which is considered as the most recalcitrant material for enzymatic hydrolysis mainly due to the high lignified structure and the nature of the lignin component. Therefore, overcoming recalcitrance of lignocellulosic biomass for converting carbohydrates into sugar that can subsequently be converted into biobased fuels and biobased products is the primary technical and economic challenge for bioconversion process. This study was mainly reviewed on the research trend of the enhancement of enzymatic hydrolysis for lignocellulosic biomass after pretreatment in bioethanol production process.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.06a
• /
• pp.471-471
• /
• 2005