The effect of different glucose concentrations (10-100 g/l) on succinic acid production by Actinobacillus succinogenes was studied. The maximum succinic acid concentration obtained was 33.8 g/l from 54.7 g/l of glucose. Productivities, conversion yields, and specific rates decreased when the amount of initial glucose was increased. The growth stopped with 22 g/l of acid mixture produced (succinic, formic, and acetic acids) and succinic acid production stopped with 45 g/l of acid mixture produced. These results point to a double inhibitory effect by glucose and products on growth and succinic acid production. The inhibition phenomenon was adequately described by Jerusalimsky equations for specific rate of growth and specific rate of succinic acid production. These expressions helped to quantify substrate and product inhibition effects. (C) 2008 Elsevier Ltd. All rights reserved.