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 ofnickel into aquatic ecosystems with a negativeimpact on living organisms. Cyanobacteriahave an important role in regulating pollution,reducting dissolved nickel in water, and increasingthe mineral’s sedimentation. Recentlythe presence of phenylalanine ammonia lyaseenzyme has been proved in cyanobacteria.This study aims to investigate the correlationbetween phenylalanine ammonia lyase activityand the rate of nickel absorption. For thispurpose, a number of cyanobacteria Anabaenaspecies, endogenous to Iran, were prepared bydry and wet treatment with nickel. The nickeluptake was evaluated by atomic absorption andcomparison with a standard curve .The phenylalanineammonia lyase was extracted fromcyanobacteria and the enzyme activity wasmeasured at different pH values. The resultsshowed that some of the samples under studyhad remarkable ability to absorb nickel and thatthere were significant differences in the activityof the enzyme phenylalanine ammonia lyase atdifferent pH values. This study established therelationship between the level of activity of thisenzyme and the rate of nickel absorption.

Keywords:

Absorbtion , Nickle , Cyanobacteria , Ammonia-lyase