Studies on the biosynthesis of L-aspartate 4-carboxy-lyase by Cunninghamella elegans and Penicillium citrinum

Cell-free extracts of Cunninghamella elegans and Penicillium citrinum contained L-aspartate 4-carboxylyase which catalyzes the beta- decarboxylation of L-aspartate to alpha-alanine and CO2. The enzyme was produced during the logarithmic phase of growth of the 2 organisms and maximum yield was obtained after 4 days incubation. The optimal pH range for L-aspartate 4-carboxylyase synthesis by C. elegans was 5 - 6, while for P. citrinum enzyme pH 5 was the optimal. L-aspartate 4-carboxylyase of both organisms was induced by L-aspartate and L- asparagine. L-aspartate concentration of 3.5 g/l was the optimal for L-aspartate 4-carboxylyase formation by both cultures. The effect of different carbon sources and metal salts on enzyme synthesis and growth of the two organisms was investigated