Diversity and enzymatic profiling of halotolerant micromycetes from Sebkha El Melah, a Saharan salt flat in southern Tunisia

Biomed Res Int. 2014:2014:439197. doi: 10.1155/2014/439197. Epub 2014 Jul 16.

Abstract

Twenty-one moderately halotolerant fungi have been isolated from sample ashes collected from Sebkha El Melah, a Saharan salt flat located in southern Tunisia. Based on morphology and sequence inference from the internal transcribed spacer regions, 28S rRNA gene and other specific genes such as β-tubulin, actin, calmodulin, and glyceraldehyde-3-phosphate dehydrogenase, the isolates were found to be distributed over 15 taxa belonging to 6 genera of Ascomycetes: Cladosporium (n = 3), Alternaria (n = 4), Aspergillus (n = 3), Penicillium (n = 5), Ulocladium (n = 2), and Engyodontium (n = 2). Their tolerance to different concentrations of salt in solid and liquid media was examined. Excepting Cladosporium cladosporioides JA18, all isolates were considered as alkali-halotolerant since they were able to grow in media containing 10% of salt with an initial pH 10. All isolates were resistant to oxidative stresses and low temperature whereas 5 strains belonging to Alternaria, Ulocladium, and Aspergillus genera were able to grow at 45°C. The screening of fungal strains for sets of enzyme production, namely, cellulase (CMCase), amylase, protease, lipase, and laccase, in presence of 10% NaCl, showed a variety of extracellular hydrolytic and oxidative profiles. Protease was the most abundant enzyme produced whereas laccase producers were members of the genus Cladosporium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ascomycota* / classification
  • Ascomycota* / enzymology
  • Ascomycota* / genetics
  • Ascomycota* / isolation & purification
  • Biodiversity*
  • Desert Climate*
  • Fungal Proteins / genetics*
  • Tunisia

Substances

  • Fungal Proteins