• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.26 no.2
• /
• pp.120-132
• /
• 1993

A continuous hollow fiber membrane reactor(CHFMR) was developed and optimized for the production of yellowfin sole(Limanda aspera) skin gelatin hydrolysates using trypsin. The results were summerized as follows: The $K_m$ value of the CHFMR was 2.4 times higher than that of the batch reactor, indicating reduced enzyme affinity for the substrate. The $K_2$ value of the CHFMR was 8.5 times lower than that of the batch process, showing a significant reduction in trypsin activity in the CHFMR. The optimum operating conditions for the CHFMR process were $55^{\circ}C$, pH 9.0, flux 7.79 ml/min, residence time 77min, and trypsin to substrate ratio, 0.01(w/w) After operating for 60min under the above conditions, $79\%$ of the total amount of initial gelatin was hydrolysed. Enzyme leakage was observed through the 10,000 MWCO membrane after the 20min of reactor operation, while none occurred after 5hr. Total enzyme leakage was about $12.95\%$ at $55^{\circ}C$ for 5hrs. However, there was no apparent correlation between enzyme leakage and substrate hydrolysis. The membrane has a significant effect on trypsin activity loss for 60min of the CHFMR operation. The CHFMR operating with the membrane lost $34\%$ of the initial activity versus a $23\%$ loss of activity after 3hr in the continuous reactor lacking the hollow fiber membrane. The measurement of fouling property showed that relative flux reduction was $91\%$ and flux recover rate was $92\%$ at $10\%$ substrate solution. The productivity(378.85mg product/mg enzyme) of the CHFMR was more than 4 times higher than that of the batch reactor at $55^{\circ}C$.

• Journal of Korean Society of Forest Science
• /
• v.43 no.1
• /
• pp.31-34
• /
• 1979

In this study, enzymatic hydrolysis of the substrate of the waste wood of Cortinellus edodes was investigated using crude cellulase preparation of Trichoderma viride Pers. ex. Fr. SANK 16374. The crude cellulase was produced by the submerged culture process and produced in the culture fluid was salted out quantitatively by the use of ammonium sulfate. Reducing sugar was determined by the dinitrosalisylic acid (DNS) method. 1. The chemical composition of the waste wood was crude protein 2.26%, c. fat 2.57%, c. fibre 44.60%, c. ash 5.58% and lignin 13.62%. In amino acid composition, no cystine and methionine was showed, but trace amount of Vitamin A, $B_1$, and $B_2$, niacine and chloride were detected. (Table 1) 2. As heat treatment of the substrate was found to produce the highest reducing sugar yield being reacted for 48hr. with T.v cellulase, the substrate was heated to $190{\pm}5^{\circ}C$. for 45 min. either before or immediately after milling. 3. The substrate heated and ball milled at $190{\pm}5^{\circ}C$. for 45 min. the reducing sugar yield reached to 11.5%. 4. The substrate without any treatment was found to produce the highest reducing sugar yield being reacted 72hr. with T. v cellulase, the reducing sugar yield reached to 10.1%. 5. The rate of reducing sugar per each treated substrate was decreased by the order of the substrated, heated and then ball milled at $190{\pm}5^{\circ}C$. for 45 min. (11.5%)> without any treatment (10.1)> ball milled and heated at $190{\pm}5^{\circ}C$. for 45 min. (6.9%). 6. Saccharification of waste wood has been shown to be possible by heat treated and milling the substrate in contact with cellulase. And it is likely to be recommended that the waste wood may be valuable for raw materials of saccharification.

• Journal of the Korean Wood Science and Technology
• /
• v.38 no.6
• /
• pp.547-560
• /
• 2010

The optimum culture condition of Schizophyllum commune for the cellulase production and its enzymatic characteristics for saccharification of cellulosic biomass were analyzed. S. commune secrets ${\beta}$-1,4-xylosidase (BXL) and cellulases, including endo-${\beta}$-1,4-glucanase (EG), cellobiohydrolase (CBH), and ${\beta}$-glucosidase (BGL). The optimum reaction temperature for all cellulases was $50^{\circ}C$ and the thermostable range was $30{\sim}40^{\circ}C$C. The optimum reaction pH for all cellulases was 5.5 in a range of temperature from $0^{\circ}C$ to $55^{\circ}C$. The best nutritions for the cellulase production of S. commune among tested nutrients were 2% cellulose for the carbon source and corn steep liquor or peptone/yeast extract for the nitrogen source without vitamins. The environmental culture condition for the cellulase production was 5.5~6.0 for pH at $25{\sim}30^{\circ}C$. The enzyme activities of EG, BGL, CBH, and BXL were 3670.5, 631.9, 398.5, and 15.2 U/$m{\ell}$, respectively, after concentration forty times from the culture broth of S. commune which was grown at the optimized culture condition. Alternative filter paper unit assay showed 11 FPU/$m{\ell}$ enzyme activity. The saccharification tests using cellulase of S. commune showed the low saccharification rate on tested hardwoods but a high value of 50.5% on cellulose, respectively. The saccharification rate (50.5%) of cellulose by cellulase produced in this work is higher than 45.7% in the commercial enzyme (Celluclast 1.5L, 30 FPU/g, glucan).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.17 no.2
• /
• pp.117-124
• /
• 1984

Sarine scrap usually comprises about $40\%$ of the raw fish in processing. The purpose of this study is to establish the desirable methods for proteinaceous materials from the sardine scrap through autolysis or enzymatic digestion and to convert them into useful by-products such as sardine sauce. Sardine scrap was chopped and mixed with equal weight of water, and be hydrolyzed them by autolysis and/or by addition of commercial proteolytic enzyme and various concentrations of sodium chloride. The optimal conditions for hydrolysis of sardine scrap were revealed in temperature at $55^{\circ}C$ and 4 hours digestion with bromelain($0.4\%$) and commercial complex enzyme ($6.0\%$), and those conditions were also applicated in autolysis. The maximum hydrolyzing rate of protein and released amino nitrogen were $82.5\%,\;5.2\%$ through autolysis, $84.3\%,\;5.8\%$ by bromelain digestion and $92.5\%,\;5.9\%$ by complex enzyme, respectively. In the products prepared from sardine scrap through autolysis or bromelain digestion, hypoxanthine was dominant, as $17.4 {\mu}mole/g$, dry matter for autolysis and $16.0 {\mu}mole/g$, dry matter, for bromelain digestion among the nucleotidcs and their related compounds, respectively. The abundant free amino acids were leucine, glutamic acid, lysnie, valine and alanine. The contents of those amino acids were $51.3\%,\;48.3\%$ of the total free amino acids, respectively. And the contents of 5'-IMP and TMAO were negligible but total creatinine was developed in value from $9.2\%\;to\;10\%$ of total extracted nitrogen. The flavor of sardine sauce prepared from sardine scrap by autolysis or enzyme digestion were not inferior to that of traditional Korean soy sauce by sensory evaluation.

• Korean Journal of Food Science and Technology
• /
• v.51 no.5
• /
• pp.480-485
• /
• 2019

The present study was conducted to compare antioxidant capacities of protein hydrolysates from four different edible insects (Protaetia brevitarsis larvae, Allomyrina dichotoma larvae, Gryllus bimaculatus imago, and Tenebrio molitor larvae) which have recently been registered as food varieties in Korea. Protein hydrolysates were prepared from each insect using enzymatic hydrolysis using alcalase, and were then separated into a fraction containing ${\leq}3kDa$. According to $RC_{50}$ values and trolox equivalent antioxidant capacity results obtained from five different antioxidant analyses, the Gryllus bimaculatus (GB) hydrolysate showed relatively high levels of antioxidant capacity and, in particular, the GB hydrolysate showed considerably strong antioxidant activities in 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and in ferric reducing antioxidant power (FRAP) assays. The GB hydrolysate also showed the strongest inhibitory effect on peroxidation of linoleic acid, and its rate of inhibition at $100{\mu}g/mL$ on day 3 of treatment was 60.26%. These results suggest that protein hydrolysates from edible insects including GB represent potential sources of natural antioxidants.