• Applied Biological Chemistry
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• v.32 no.4
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• pp.435-440
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• 1989

To improve alkaline protease producing strain by protoplast fusion, a strain of Bacillus sp. was treated with $100{\mu}g/ml$ NTG (N-methyl-N'-itro-N-nitrosoguanidine) for 45 minutes and mutants of Bacillus subtilts $Arg^-,\;Try^-,\;His^-$ and $Ade^-$ were isolated. The frequency of protoplast formation was about 99%, when teas of exponential phase were treated with $200{\mu}g/ml$ lysozyme at $42^{\circ}C$ for $10{\sim}30$ minutes. In a regeneration medium containing 0.3M sodium succinate, 2.0% polyvinylpyrrolidone, 0.5% casamino acid, 10mM $MgCI_2$ and 20mM $CaCI_2$, regeneration frequency cf the isolated Bacillus subtilis strains was 25.2%. The fusion frequency between mutant was from $2.1{\times}10^{-5}$ to $8.1{\times}10^{-5}$ under optimum condition.

• Applied Biological Chemistry
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• v.40 no.5
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• pp.365-368
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• 1997

This study was carried out to investigate the optimum mashing and maturing conditions for Korean traditional Kanjang(soy sauce) production and to reduce the fermentation period. The effects of maturing time of soy sauce mash, maturing temperature, salt concentration and the ratio of Meju to salt brine on the quality of Kaniang(total nitrogen, pH and color) were examined. Soy sauce pigments and about 90% of N constituents contained in soybean Meju(Koji) in soy sauce mash were degraded and solubilized into liquid portion (soy sauce) of the mash within five days of maturing at $30^{\circ}C$ with the mashing ratio(weight/volume) of 1 : 4 of soybean(as raw soybean) to 20% salt brine. No remarkable effects of soy sauce maturing temperature in the range of $5^{\circ}C{\sim}30^{\circ}$ on the digestion and solubilization of N components and pigment extraction during five days of soy sauce mash maturing were observed. Optimum mashing salt brine concentration for the digestion and solubilization of N components and pigment extraction during soy sauce maturing at $30^{\circ}C$ were observed to be in the range of $15{\sim}20%$. The suitable mashing ratio of Meju to salt brine (wt./vol.) to match N content of the standards of identity of Korean traditional Kanjang(soy sauce) was found to be below 1 : 5.