Sulfate-reducing bacteria from mangrove swamps. 2. Their ecology and physiology

Abstract

Sulfate-reducing bacteria (SRB) have been enumerated and physiologically characterized in three mangrove stations along the Zuari Estuary, Goa, India. The substrates for counting were lactate, acetate, propionate, butyrate and benzoate. Benzoate oxidizing SRB were widespread and occurred in numbers up to 6.62 x 103/g dry sediment. The next highest in number were lactate utilizing SRB. On an average there were more propionate and butyrate utilizers than acetate utilizers. While Agasaim at the mouth of the estuary harboured highest number of lactate oxidizers, none were detected at Mirabaug upstream during the samplings. The SRB shared many characteristics with Desulfovibrio desulfuricans, D. desulfuricans aestuarii, D. salexigens, Desulfotomaculum orientis, D. acetoxidans, Desulfosarcina variabilis, Desulfococcus multivorans, and Desulfovibrio sapovorons. It is suggested that sulfate-reduction in these mangrove swamps may not only be mediated through hydrogen, lactate and acetate but also through propionate, butyrate and to some extent through benzoate.