ISOLATION OF NEW 6-METHYLNICOTINIC-ACID-DEGRADING BACTERIA, ONE OF WHICH CATALYZES THE REGIOSELECTIVE HYDROXYLATION OF NICOTINIC-ACID AT POSITION C2

2-Hydroxynicotinic acid is an important building block for herbicides and pharmaceuticals. Enrichment strategies to increase the chances of finding microorganisms capable of hydroxylating at the C2 position and to avoid the degradation of nicotinic acid via the usual intermediate , 6-hydroxynicotinic acid, were used. Three bacterial strains (Mena 23 /3-3c, Mena 25/4-1, and Mena 25/4-3) were isolated from enrichment cul tures with 6-methylnicotinic acid as the sole source of carbon and ene rgy. Partial characterization of these strains indicated that they rep resent new bacterial species. All three strains completely degraded 6- methylnicotinic acid, and evidence is presented that the first step in the degradation pathway of strain Mena 23/3-3c is hydroxylation at th e C2 position. Resting cells of this strain grown on 6-methylnicotinic acid also hydroxylated nicotinic acid at the C2 position, but did not further degrade the product, Strain Mena 23/3-3c showed the highest d egree of 16S rRNA sequence similarity to members of the genera Ralston ia and Burkholderia.