• Journal of Microbiology and Biotechnology
• /
• 제24권12호
• /
• pp.1622-1628
• /
• 2014

DagA, a ${\beta}$-agarase, was produced by cultivating a recombinant Streptomyces lividans in a glucose medium or a mixed-sugar medium simulating microalgae hydrolysate. The optimum composition of the glucose medium was identified as 25 g/l glucose, 10 g/l yeast extract, and $5g/l\;MgCl_2{\cdot}6H_2O$. With this, a DagA activity of 7.26 U/ml could be obtained. When a mixed-sugar medium containing 25 g/l of sugars was used, a DagA activity of 4.81 U/ml was obtained with very low substrate utilization efficiency owing to the catabolic repression of glucose against the other sugars. When glucose and galactose were removed from the medium, an unexpectedly high DagA activity of about 8.7 U/ml was obtained, even though a smaller amount of sugars was used. It is recommended for better substrate utilization and process economics that glucose and galactose be eliminated from the medium, by being consumed by some other useful applications, before the production of DagA.

• 한국조리학회지
• /
• 제24권2호
• /
• pp.103-111
• /
• 2018

The objectives of the present study were to examine the antioxidant activity of autofocusing fractions from egg white protein hydrolysates and obtain higher antioxidant peptide fraction, which could be applied to the food model system. Alkaline protease hydrolysate of egg white protein exerted higher antioxidant activities than other protein hydrolysates and were fractionated on the basis of the amphoteric nature of sample peptides by preparative isoelectric focusing without toxic solvents and reagents, which is termed autofocusing. Neutral and basic fractions showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than the acidic fractions. The acidic and neutral fractions showed higher hydroxyl (OH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) values than the basic fractions. The acidic fractions showed higher metal chelating activity than basic fractions. Antioxidant activities of some autofocusing fractions except for ORAC showed higher compared to the crude hydrolysate. These results suggest that peptides fractions from egg white protein are effective antioxidant, and that autofocusing could be useful to increase antioxidant activity for application to food system.

• 한국해양바이오학회지
• /
• 제10권1호
• /
• pp.1-8
• /
• 2018

The objective of this study was to purify and characterize the ${\beta}-secretase$ inhibitor from enzymatic hydrolysates of blackfin flounder muscle, for development of a novel anti-dementia agent that may be used in the drug or functional food industries. ${\beta}-secretase$ inhibitory peptide was purified from various enzymatic hydrolysates of blackfin flounder muscle. Among six enzymatic hydrolysates, the Alcalase hydrolysate revealed highest ${\beta}-secretase$ inhibitory activity. Consecutive purification of the blackfin flounder muscle hydrolysate using Sephadex G-25 column chromatography and octadecylsilane C18 reversed phase HPLC techniques were used to isolate a potent ${\beta}-secretase$ inhibitory peptide composed of 5 amino acids, Leu-Thr-Gln-Asp-Trp (MW: 526.7 Da). The $IC_{50}$ value of purified ${\beta}-secretase$ inhibitory peptide was $126.93{\mu}M$. Results of this study suggest that peptides derived from blackfin flounder muscle may be beneficial as anti-dementia compounds in functional foods or as pharmaceuticals.

• KSBB Journal
• /
• 제24권5호
• /
• pp.415-419
• /
• 2009

본 연구에서는 리그노셀룰로스 가수분해물과 유사한 조성을 갖는 합성 용액을 이용하여 무독화 실험을 진행하였다. 생물학적 무독화 방법으로는 peroxidase와 laccase와 같은 효소를 이용하였고, 이온교환과 흡착과 같은 물리화학적 방법으로는 이온교환수지와 활성탄을 이용하였다. 효소 중 peroxidase는 페놀계 화합물의 제거에 탁월한 효율을 보였으며, 5-HMF와 furfural은 활성탄에 의해 거의 모두 제거되었고, 아세트산은 음이온교환수지를 사용하는 것이 가장 효율적이었다. 활성탄과 이온교환수지는 다소간의 당손실을 일으켰다. 무독화 방법은 당화액에 포함되어 있는 저해물질의 조성을 고려하여 결정되어야 한다.

• KSBB Journal
• /
• 제28권3호
• /
• pp.196-201
• /
• 2013

Silkworm-derived silk materials which contain 45 to 55% protein (18 amino acids, including 8 essential amino acids) have free radical-scavenging activities. In the present study, we investigated the whitening and anti-aging effects of silkworm gland under various conditions with B16F1 melanoma cells and human dermal fibroblasts. To evaluate the toxicity of soluble gland hydrolysate (SGH), mouse-derived B16F1 melanoma cells were treated with 0.2~5 mg/mL, cytotoxicity was not observed at all concentrations. The tyrosinase and elastase activities were significantly decreased as dosage levels of SGH increased. In addition, cell death was decreased by treated with SGH and antioxidative activity was the most effective in the SGH treatment. These findings suggest that SGH may be used as a potential functional biomaterial in having the skin whitening effect and anti-aging activity by inhibition of tyrosinase and elastase activities.

• Preventive Nutrition and Food Science
• /
• 제20권4호
• /
• pp.284-291
• /
• 2015

In this study, we attempted to enrich cyclo-His-Pro (CHP) using enzymatic hydrolysis of yeast and to evaluate the functionality of yeast hydrolysate (YH)-enriched CHP. Flavourzyme offered a better performance in enhancing CHP content than other proteases. The CHP enrichment conditions were optimized as follows: addition of 1% Flavourzyme, 48-h incubation at 60oC, and pH 6.0. The CHP content significantly increased by 20-fold after ultra-filtration (UF). Maximal CHP translation was obtained after heating for 8 h at 50oC and pH 7.0. YH showed poor foaming capacity between pH 3.0 to 9.0. The emulsifying activities of YHs were slightly higher at near acidic pH. Increase in heating temperature and time resulted in decreased CHP content. The results indicate that YH is more heat stable after UF. Therefore, the CHP in YH after UF can be used as a food additive with physiological CHP activity and high heat stability.

• Preventive Nutrition and Food Science
• /
• 제10권3호
• /
• pp.239-243
• /
• 2005

Angiotensin I-converting enzyme (ACE) inhibitory activities of elk antler hydrolysates prepared with three kinds of proteases, pepsin, trypsin and $\alpha-chymotrypsin$, were investigated. The ACE inhibitory activity of the pepsinolytic hydrolysate was the highest with an $IC_{50}$ value of $9.3\mu g/mL.$ In addition, three kinds of pepsinolytic hydrolysates with relatively high molecular weights (over 10,000 Da), medium molecular weights (5,000 to 10,000 Da), and low molecular weights (below 5,000 Da) were fractionated using an ultrafiltration membrane system. The below 5,000 Da hydrolysate exhibited the highest ACE inhibitory activity. These results indicate that the pepsinolytic hydrolysates of elk velvet antler could be a good source of peptides with ACE inhibitory activity.

• Journal of Microbiology and Biotechnology
• /
• 제25권1호
• /
• pp.26-32
• /
• 2015

Four types of straw, namely, soybean, wheat, corn, and rice, were investigated for use in lactic acid production. These straws were mainly composed of cellulose, hemicellulose, and lignin. After pretreatment with ammonia, the cellulose content increased, whereas the hemicellulose and lignin contents decreased. Analytical results also showed that the liquid enzymatic hydrolysates were primarily composed of glucose, xylose, and cellobiose. Preliminary experiments showed that a higher lactic acid concentration could be obtained from the wheat and soybean straw. However, soybean straw was chosen as the substrate for lactic acid production owing to its high protein content. The maximum lactic acid yield (0.8 g/g) and lactic acid productivity (0.61 g/(l/h)) were obtained with an initial reducing sugar concentration of 35 g/l at 30℃ when using Lactobacillus casei (10% inoculum) for a 42 h fermentation period. Thus, the experimental results demonstrated the feasibility of using a soybean straw enzymatic hydrolysate as a substrate for lactic acid production.

• Fisheries and Aquatic Sciences
• /
• 제16권2호
• /
• pp.71-78
• /
• 2013

Subcritical water hydrolysis was carried out in a batch reactor to produce valuable materials, such as low-molecular weight (MW) peptides and essential amino acids with antioxidant properties, from heat-dried squid viscera. Hydrolysis of squid viscera was performed at 160 to $280^{\circ}C$ for 3 min. The yield was increased by increasing the temperature and pressure, while the protein content of squid viscera hydrolysate decreased with increasing temperature. Low-MW peptides were detected in all hydrolysates by sodium dodecyl sulfate polyacrylamide gel electrophoresis. The highest yields of free and structural amino acids in heat-dried squid viscera hydrolysate were at $160^{\circ}C$ and were $411.95{\pm}1.15$ and $346.62{\pm}1.25$ mg/100 g, respectively. All essential amino acids were detected in viscera hydrolysates; leucine was the most abundant. Antioxidant activities of hydrolysates were highest at $220^{\circ}C$. Greater than $98{\pm}0.26%$ of the ABTS antioxidant activity was retained in hydrolysates after long-term heat treatment.

• Journal of Applied Biological Chemistry
• /
• 제60권4호
• /
• pp.373-381
• /
• 2017

Hippocampus abdominalis, the big belly sea horse, is widely known for its medicinal value in Chinese folk medicine. In this study, extract obtained by proteolytic degradation of this species was investigated for its effects on skeletal muscle development, both in vitro and in vivo. Muscle cell lines ($C_2C_{12}$ and $L_6$) treated with the bioactive peptide did not have any detrimental effects on the cell viability, which was above 80%. Optical microscopy analysis on the morphology of the sea horse extract (SHE)-treated cells showed enhanced differentiating ability with myotube formation. Moreover, cells incubated with the hydrolysate displayed decreased proliferation rate, as recorded by the electric cell substrate impedance sensing system, thereby supporting enhanced differentiation. For a period of 12 weeks, mice models were fed with SHE and simultaneously subjected to treadmill exercise, which increased the expression of Myogenin, a key myogenic regulatory factor. In addition, there was an increase in the expression of AMPK- and Cytochrome C, both of which are important in mitochondrial biogenesis. Thus, the SHE from Hippocampus abdominalis can be a promising candidate as protein supplement aiding muscle development.