Carrier-mediated acetate uptake in Corynebacterium glutamicum

Acetate is effectively taken up by whole cells of Corynebacterium glutamicum via a specific carrier with a pH optimum of 8. The K _m of acetate uptake was 50 μM and the V _max 25–35 nmol/mg dw min. The activation energy was determined to be 70 kJ/mol. Acetate uptake was competitively inhibited by propionate with a K _i of about 30 μM and blocked by addition of sulfhydryl reagents. The transport activity was clearly dependent on the membrane potential, but independent of the presence of Na⁺-ions. It is concluded that uptake of acetate proceeds by a secondary, proton coupled mechanism.