• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.878-884
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• 1996

A bacterial strain, designated as Bacillu sp. IJ-3 strain, was shown to produce the extracellular soy protein coagulating enzyme and culture conditions for the production of enzyme by this microbial strain was investigated. The culture medium giving a maximum soy protein coagulating activity was consist of 20%(w/v) soymilk, 2.0%(w/v) glucose, 4.0%(w/v) yeast extract, 5.0%(w/v) polypeptone and 1.0%(w/v) potassium phosphate, monobasic. Initial pH was optimal at 6.0 and the enzyme activity in the culture usually reached a maximal level of fermentation at $35^{\circ}C.$ After the culture medium adjustment where required, enzyme activity was reached maximum at 72 hour of cultivation but this enzyme activity was reduced quickly. It can be assumed that Bacillu sp. IJ-3 strain enzyme has a specificity toward the 75 globulin.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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• pp.973-979
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• 1994

Microorganisms, including the strain IJ-3 isolated from soil, were found to secrete an extracellular soybean protein coagulating enzyme and the strain, IJ-3 was identified as Genus Bacillus according to the Bergey's manual . The enzyme coagulated protein in soymilk , thus forming a curd at pHs 5.8-6.4 and at 55-75℃. The optimum temperature for soybean protein coagulating activity was 65-75℃ and the enzyme was stable at temperature below 50℃ and was found to be stable with about 60-100% of the original activity at a with pH ranges(pH6-7). The molecular weight of enzyme was estimated to be 28,000 by SDS-PAGE. The curd formed with the enzyme from Bacilus sp. IJ-3 has a smooth texture, and a mild taste without any bitterness or a beany flavor.