Microbial desulphonation and β-naphthol formation from 2-naphthalenesulphonic acid

Under sulphate limitation, axenic batch cultures of strain RMNT and the mixed culture Co 27 isolated from sulphurous springs metabolize 2-naphthalenesulphonic acid (2NS) and use sulphonate as a source of sulphur. The main metabolite was identified as 2-naphthol. The effects of various culture conditions and atmosphere compositions on the efficiency of release of β-naphthol were studied. Glucose was added to some culture medium and pH was controlled in some cultures. The results collected included β-naphthol released during batch incubation. The release of β-naphthol varied with the pH of the medium, dark incubation, glucose concentration and oxygenation. Mixed cultures were better β-naphthol producers than pure cultures. Microbial strains desulphonated the aromatic compound, but did not utilize it as a carbon source. Bacterial strains present in the mixed culture were identified: three were of the genus Bacillus and two others were Kingella and Corynebacterium.