Takeda Chemical Industries, Inc.

Isamu Nakatsui

Yukihiro Kanegae

Yoshio Sugiyama

Kazutsugu Kimura

Akira Yutani

The present invention comprises a method of producing .beta.-1,3-glucan wherein a microbe capable of producing .beta.-1,3-glucan is cultured in a medium containing as a nitrogen source an ammonium salt of an organic carboxylic acid the microbe can assimilate wherein the .beta.-1,3-glucan is produced and accumulated, and then harvesting. The .beta.-1,3-glucan production method of the present invention does not require addition of a pH regulator such as calcium carbonate or alkali ions, since the medium does not decrease in pH because a microbe capable of producing .beta.-1,3-glucan is cultured in a medium containing as a nitrogen source an ammonium salt of an organic carboxylic acid which the microbe can assimilate. For this reason, cultivation is not adversely affected, nor does any salt form in the medium, aspects which facilitate purification of said glucan, offering an industrially excellent production method. Moreover, the method of the present invention makes it feasible to produce .beta.-1,3-glucan at high productivity and high yield relative to sugar.

Method of producing .beta.-1,3-glucan

Disclosed is a microorganism belonging to the genus Agrobacterium which is able to produce .beta.-1,3-glucan and is either deficient or defective in phosphoenolpyruvate carboxykinase activity. Preferred microorganisms are mutants of Agrobacterium sp. biovar I. Particularly preferred mutant strains are Agrobacterium sp. biovar I GA-27 (FERM BP-4350) and Agrobacterium sp. biovar I GA-33 (FERM BP-4351).

Mutant strains of agrobacterium for producing .beta.-1,3-glucan

In a fermentive production of polyglutamic acid and a salt thereof, the accumulation of polyglutamic acid can be markedly increased in a very simple manner by adding an alkaline earth metal ion to the medium in a concentration of not less than 0.05 mole per liter.

Method for producing polyglutamic acid or a salt thereof

L-Glutamic acid is produced in a high yield by cultivating an L-glutamic acid-producing microorganism which requires oleic acid but does not require biotin for growth in a culture medium containing an oleic acid compound and a biotin compound of no less than 100 .mu.g/liter as biotin, with carbohydrate and acetic acid as carbon sources being maintained in a weight ratio of about 80:20 through about 40:60.

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Kobe, Japan

Isamu Nakatsui