Every organism has different potential to accumulate NO3-
from the environment. Nitrate reduction processes are perhaps most significant in maintaining water quality by alteration of nitrate to nitrite. A comparative study between the nitrate reductase NR activity of green and blue green algae in presence of heavy metalsis being conducted to present a situation where nitrate reductase process may be affected in presence of heavy metals. Metals interacted negatively with the nitrate reductase activity of a blue green alga, Anacystis nidulans
and green algae, Chlorella vulgaris
in both free and immobilized state. The activity was more repressed in C. vulgaris
in presence of Ni compared to Zn and Cd. However, Cd was more toxic to NR activity in A. nidulans
(free state). Metal dependent variation between free and immobilized cells were found to be significant (P< 0.01) however, the concentration dependent pattern in the activity between free and immobilized state was non significant in both the test organisms. C.vulgaris
is more efficient in conversion of nitrate to nitrite compared to A.nidulans in presence of heavy metals.