Phenylalanine Ammonia-lyase Enzyme as a New Marker for Selection of Cyanobacteria for Absorption of Nickel in the Aquatic Environment

Industrial activity can cause the release of nickel into aquatic ecosystems with a negative impact on living organisms. Cyanobacteria have an important role in regulating pollution, reducting dissolved nickel in water, and increasing the mineral’s sedimentation. Recently the presence of phenylalanine ammonia lyase enzyme has been proved in cyanobacteria. This study aims to investigate the correlation between phenylalanine ammonia lyase activity and the rate of nickel absorption. For this purpose, a number of cyanobacteria Anabaena species, endogenous to Iran, were prepared by dry and wet treatment with nickel. The nickel uptake was evaluated by atomic absorption and comparison with a standard curve .The phenylalanine ammonia lyase was extracted from cyanobacteria and the enzyme activity was measured at different pH values. The results showed that some of the samples under study had remarkable ability to absorb nickel and that there were significant differences in the activity of the enzyme phenylalanine ammonia lyase at different pH values. This study established the relationship between the level of activity of this enzyme and the rate of nickel absorption.