• Journal of Microbiology and Biotechnology
• /
• v.27 no.12
• /
• pp.2180-2189
• /
• 2017

Psychrophilic phytases suitable for aquaculture are rare. In this study, a phytase of the histidine acid phosphatase (HAP) family was identified in Morchella importuna, a psychrophilic mushroom. The phytase showed 38% identity with Aspergillus niger PhyB, which was the closest hit. The M. importuna phytase was overexpressed in Pichia pastoris, purified, and characterized. The phytase had an optimum temperature at $25^{\circ}C$, which is the lowest among all the known phytases to our best knowledge. The optimum pH (6.5) is higher than most of the known HAP phytases, which is fit for the weak acidic condition in fish gut. At the optimum pH and temperature, MiPhyA showed the maximum activity level ($2,384.6{\pm}90.4{\mu}mol{\cdot}min^{-1}{\cdot}mg^{-1}$, suggesting that the enzyme possesses a higher activity level over many known phytases at low temperatures. The phytate-degrading efficacy was tested on three common feed materials (soybean meal/rapeseed meal/corn meal) and was compared with the well-known phytases of Escherichia coli and A. niger. When using the same amount of activity units, MiPhyA could yield at least $3{\times}$ more inorganic phosphate than the two reference phytases. When using the same weight of protein, MiPhyA could yield at least $5{\times}$ more inorganic phosphate than the other two. Since it could degrade phytate in feed materials efficiently under low temperature and weak acidic conditions, which are common for aquacultural application, MiPhyA might be a promising candidate as a feed additive enzyme.

• Applied Biological Chemistry
• /
• v.33 no.2
• /
• pp.161-168
• /
• 1990

In order to investigate systematically characteristics of improved Kochujang in comparision with traditional Kochujang, changes of components in curing of two Kochujangs, enzyme activities of koji and Meju, and effects of salt and red pepper were measured. And it was found that the large differences of amino nitrogen and reducing sugar contents were appeared in the initial stage of the curing period, but the changes were parallel thereafter. The protease activity of koji was maximum in weak acidic pH and that of Meju was maximum in neutral pH. The optimum condition of substrate digestion was three hours at $60^{\circ}C$, and that was more effective than curing at room temperature. The activities of protease and saccharogenic amylase were decreased remarkably by adding salt and red pepper, Therefore, to decompose starch and protein effectively, the addition of salt and red pepper after substrate digestion was more favorable.

• Fashion & Textile Research Journal
• /
• v.19 no.5
• /
• pp.620-625
• /
• 2017

In this study, the dyeing conditions(temperature, time, concentration) are changed from various conditions on wool fabrics by using corydalis tuber extract in order to develop new natural dyes. The purpose of this study is to improve the dyeability, color fastness, and functionality and to derive optimal dyeing conditions by comparing and analyzing the changes of K/S values and surface color by dyeing pH changes, mordant method, and mordant type. As a result of the experiment, the optimum dyeing condition of the wool fabrics is shown dyeing temperature:$80^{\circ}C$, dyeing time:90min, dyeing concentration:100%. The dyeability by pH variants of corydalis tuber extract indicates that K/S values is higher alkaline than acidic. The mordant method of corydalis tuber extract showed pre-mordant has high K/S values. In terms of color fastness, marked improvement has not been shown despite of mordant treatment on wool fabrics. In particular, color change of color fastness to washing, color fastness to light indicates the low fastness. In addition, the functionality such as antibacterial activities and deodorization can be given at dyeing with corydalis tuber extract thus it is expected to be applied to underwear or apparel products for the elderly and infirm and children with weak skin that required high functionality.