THE EFFECT OF Na + /Mg 2+ RATIO ON THE AMYLASE ACTIVITY OF HALOARCHAEA ISOLATED FROM TECHIRGHIOL LAKE, ROMANIA, A LOW SALT ENVIRONMENT

A relatively large number of haloarchaea was isolated from a Techirghiol Lake, located in the proximity of the Black Sea coast, in Romania. Although this lake is characterized by salinity not higher than 60 g per liter, it harbors haloarchaea belonging to Haloferax and Halorubrum genera. The isolated strains were able to hydrolyze starch, a process that appeared to be influenced by Na + /Mg 2+ ratio. The increasing NaCl concentration conducted to decreasing or lost of amylase activity. The different requirements for Mg 2+ for growth revealed the effect of this compound on the metabolism of halophilic archaea, and in particular on the process of starch hydrolysis. The registered data revealed that increasing salinity decreased the starch hydrolysis by the haloarchaeal strains isolated from salt lakes containing low salt concentrations.