Metal resistance of halotolerant fungi from mangroves and salterns of Goa, India

Abstract

Filamentous salt-tolerant fungi were isolated from mangroves and salterns of Goa, India; Aspergillus and Penicillium species were predominant amongst these. The isolates were found to have high levels of tolerance to sodium chloride and showed resistance to salts of heavy metals Pb2+, Cu2+ and Cd2+. Species belonging to Penicillium showed highest levels of halotolerance as well as resistance to heavy metals, the single isolate of a triverticillate morphotype of Penicillium obtained, showing the highest resistance. The aspergilli also displayed fairly high halotolerance as well as metal resistance, with isolates of A. niger and A. flavus showing higher levels of resistance. The other isolates belonged to the genera Paecilomyces, Fusarium, Alternaria and Cladosporium. Of these, Paecilomyces showed a fair amount of halotolerance; the others showed lower tolerance. Resistance to the heavy metals tested was poor in the isolates obtained from these genera. Amongst the isolates obtained, those of Aspergillus having a radiate, biseriate spore arrangement, and the single triverticillate morphotype of Penicillium displayed a higher degree of resistance to heavy metals. It is suggested that mechanism of resistance in these fungi could be phylogenetically related.