The Study of Enzymatic Activity of Mutant Strain Rhizopus oryzae with L-Malic Acid Accumulation

Abstract:

A stable and efficient L-Malic acid accumulation mutant strain Rhizopus oryzae ME-M15 was discovered occasionally in the mutation breading for fumaric acid producers. Rhizopus oryzae ME-M15 gave a L-Malic acid output of 16.3 g/L on average after fermentation for 96 hours, more than 3 times than that of the parent strain ME-F10. In addition, other metabolites such as ethanol and fumaric acid were remarkably decreased in accordance with the depressed activity of the cytosolic isoenzyme of fumarase and alcohol dehydrogenase in strain ME-M15, while the activity of the pyruvate carboxylase had no significant difference.

Key words:Rhizopus oryzae, L-Malic acid, Fumarase, Pyruvate carboxylase (PC), Alcohol dehydrogenase (ADH)