Meito Sangyo Kabushiki Kaisha

Meito Sangyo Co., Ltd.

Toshihiko Higashi

Shinjiro Iwasaki

Teruhiko Beppu

Takashi Yamashita

Haruo Machida

Susumu Higashi

Yoshinori Kobayashi

A mutant fungus strain which produces a protease with low thermostability and low productivity was made from protease producing fungi and the gene coding for mutant enzyme is isolated from the mutant strain. A promoter which can function in yeast is ligated to the gene and inserted into a plasmid replicable in yeast, and the resulting plasmid is introduced into yeast. The yeast is cultured, thereby producing the mutant enzyme. Furthermore, a gene expressing an enzyme with a far lower thermostability is prepared by site-directed mutagenesis, which is introduced in yeast, thereby producing an enzyme with more distinctively reduced thermostability.

Protease with low thermostability derived from Mucor pusillus

A method for increasing the milk coagulating activity of microbial rennet obtained from Mucor pusillus microorganisms, which comprises acylating the microbial rennet in an aqueous medium by contacting the microbial rennet with succinic anhydride at a temperature of about 0.degree. C. to about 40.degree. C. and a pH of about 4 to about 10 for a time sufficient to obtain the desired increase in milk coagulating activity; and improved microbial rennet having a low PA/MCA index and a high MCA index and obtained by the aforesaid method.

Microbial rennet having increased milk coagulating activity and method

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Hachioji, Japan

Toshihiko Higashi