Morphology and phenotypic responses of haptophyceae marine microalga <i>Pavlova lutheri</i> during Cr (VI) exposure – A laboratory study

719-724Marine microalga Pavlova lutheri (NIOT-3, EMA Accession No: LT009495), which is rich in ω-3 fatty acid, flavonoids, antioxidants, etc., has been explored as a model organism to IC50 of Cr (VI) for 96 h and monitored in controlled laboratory condition to evaluate the morphological and phenotypic responses of the microalga. The study revealed declined growth rate (63.35%) and reduced pigment (chlorophyll a) production (66%) by the microalga during Cr (VI) exposure. In the micrometric study, while end to end cell length was found to be lessened by 11 %, the average cell area was observed to be reduced by 16 %. More interestingly, SEM images showed distorted morphology along with metal deposition on the cell surface corroborating with the earlier changes. FTIR spectra brought into light conclusively the involvement of the alkynes and anhydrides as major chelating ligands to bind Cr (VI) and preventing entry of Cr (VI) across the cell wall of P. lutheri during the exposure