The growing consciousness for environmental issues have stimulated the search for more sustainable biochemical processes. One of the most attracting chemicals with enormous potential in a biobased economy is succinic acid (SA, butanedioic acid or 1,2-ethanedicarboxylic acid). This compound represents the chemical building block for various high value-added substances which find applications in the detergent/surfactant, food, ion chelator and pharmaceutical markets. Nowadays, the SA market is estimated to be about 20000–30000 ton per year worldwide and its industrial manufacture is mainly based on the catalytic hydrogenation of petrochemically derived maleic acid or maleic anhydride. However, since SA is fermentative product and an intermediate of several biochemical pathways, including the tricarboxylic acid cycle, it can be produced by many microorganisms. The biological SA production at commercial scale and potentially for the commodity chemical market is still a challenging target and requires the development and the optimization of microorganisms-based processes able to guarantee high product concentrations to justify economically feasible recovery.
The aim of this paper is the conversion of a mixture of sugars, mainly containing glucose, into SA by SA-producing strain Actinobacillussuccinogens, that was isolated from the bovine rumen. It is a facultative anaerobic, pleomorphic, Gram-negative rod. Experimental tests were carried out by using Actinobacillussuccinogens bought by Culture Collection of Goteborg and by using TBS (Tryptic Soy broth) by changing the concentration of glucose as well as that of other sugars as fructose, xylose, sucrose with the main focus to evaluate the effect of the fermentation for the Actinobacillussuccinogens with the single sugars in a concentration range from 1 to 15 g/l. All the experiments were carried out in anaerobic conditions at 37°C and in a pH range 7-8 for several days. For each test, carboxylic acids and sugars were analyzed by using u-HPLC while the growth of the selected microorganism was monitored by means of a spectrophotometer at 600nm for OD tests.