The mechanism of itaconic acid formation by Aspergillus terreus. 1. The effect of acidity

Abstract

The fermentation pattern of Aspergillus terreus is different at pH 2.1 and 6.0. At pH 2.1 practically all the glucose carbon fermented is accounted for as itaconic acid, CO2 and mycelium. At pH 6.0 no itaconic acid accumulates, and the glucose carbon is converted into L-malic, succinic and fumaric acids, CO2 and mycelium. Non-proliferating mycelia, grown at pH 2.1, convert glucose into itaconic acid with about equal yields at pH 6.0 and 2.1. Non-proliferating mycelia, grown at pH 6.0, do not accumulate itaconic acid from glucose either at pH 6.0 or 2.1. However, mycelia, grown at pH 6.0 and then transferred to a full growth medium at pH 2.1, will gradually develop the ability to produce itaconic acid. Results indicate that an acid environment is necessary for formation of an essential enzyme system for the conversion of glucose into itaconic acid.