Production of kojic acid by resuspended mycelia of Aspergillus flavus

Abstract

Efforts have been made to develop a simple chemically defined resuspended mycelial system which may be used for carrying out fundamental studies regarding the mechanism of kojic acid biosynthesis. As a first step, it was found that mycelia grown in yeast extract sucrose (YES) medium and resuspended in YES medium or in 0.2 M phosphate buffer, pH 6.5, supplemented with 20% glucose or sucrose produced kojic acid almost to the same extent as in the case of growth medium. No kojic acid was formed if buffers or media used for resuspension lacked carbohydrate. Intact mycelia preincubated in buffer alone for 7 days and 3-week-old mycelia could still form kojic acid in large amounts if resuspended in buffer containing glucose. The amount of kojic acid produced by the intact mycelia was found to be more than that produced by the disrupted mycelia. In contrast with static resuspension studies, when Aspergillus flavus mycelia were resuspended in flasks placed on a rotary shaker, much smaller amounts of kojic acid were synthesized.