Effects of chromium (VI) at extreme alkaline condition (pH 11) on the survival, growth, photosystems and phycobilisome operation of the cyanobacterium Synechocystis sp. Strain FS 78

• DOI: 10.1007/s10811-021-02521-0
• Publication Date: 2021-08-18T14:03:20Z
• Authors: Shadman Shokravi; Nadia Bahavar
• Keywords: Phycobilisome; Strain (injury); Photosynthetic pigment

The cyanobacterium Synechocystis sp. strain FS 78 was recently isolated from chromium polluted paddy fields in the North of Iran. In the present work, the effect of chromium (VI) was studied at extreme alkaline conditions (pH 11) on the growth, pigment composition, function of photosystems and phycobilisomes. We monitored the cyanobacterium viability in the presence of chromium (VI) from 0.5 to 5 µM every hour up to 6 h inoculation time. An increase in growth, pigment production, photosystems and phycobilisomes activities was observed in cells grown at low concentration (0.5 µM) of chromium (VI). The toxicity of higher chromium concentrations (3.5 and 5 µM) was observed after 1 h of inoculation. Confocal laser microscopy analysis showed the toxic effect of elevated chromium (VI) concentration on viability, probably due to the damage of the photosystem and phycobilisome structures, which on the long-term was able to recover. We concluded that the combination of the three factors (extreme alkaline pH, different concentrations of Cr(VI) and time) can affect cyanobacterial behaviours individually or in combination.