Succinic acid biocatalysts

Battat et al. [87] used A. flavus ATCC 13697 as the biocatalyst for the production of malic acid from glucose in a 16-1 stirred-tank fermentor. The optimal fermentation conditions are as follows agitation rate, 350 rpm Fe +, 12 mg/1 nitrogen (as ammonium sulfate), 271 mg/1 phosphate, 1.5 mM. Total amount of CaCOj added was 90 g/1. Fermentation was carried out at 32 °C for up to 200 h. Under the aforementioned conditions, 113 g/1 of L-malic acid were produced from 120 g/1 glucose utilized with an overall productivity of 0.59 g/l/h. Based on the molar yield, it was 128% for mahc acid and 155% for total acid (malic, fumaric and succinic acid). The increase in acid accumulation during the course of incubation coincides with the increase in the activities of NAD -malate dehydrogenase, fumarase and citrate synthase. 

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