BIDIRECTIONAL TRANSFORMATION OF AROMATIC-ALDEHYDES BY DESULFOVIBRIO-DESULFURICANS UNDER NITRATE-DISSIMILATING CONDITIONS

Desulfovibrio desulfovibrio ATCC 27774 was screened for reactivity aga inst aromatic compounds during lactate-dependent, nitrate-dissimilatin g growth. Only aromatic aldehydes (benzaldehyde, 2-hydroxybenzaldehyde , 3-hydroxybenzaldehyde, 4-hydroxybenzaldehyde, vanillin, iso-vanillin and o-vanillin) were reactive and, with the exception of 2-hydroxyben zaldehyde, were stimulatory to lactate-dependent growth. Aromatic alde hydes were transformed to their corresponding benzoate and benzyl alco hol derivatives, with the ratio of benzoate-to-benzyl alcohol derivati ves being dependent upon lactate availability. In presence of lactate, aromatic aldehydes were primarily reduced to their corresponding benz yl alcohol derivatives; in the absence of lactate, aromatic aldehydes were mainly oxidized to their corresponding benzoate derivatives. In t he absence of nitrate, 3-hydroxybenzaldehyde was neither reduced nor o xidized. These results indicate that D. desulfuricans is competent in the bidirectional transformation of aromatic aldehydes under nitrate-d issimilating conditions and that the direction of transformation (i.e. reduction or oxidation) is regulated by reductant availability.