role of sodium nitrate concentration in bg-11 medium used for autotrophic growth of anabaena vaginicola cyanobacterium

Because of its multiple applications in biotechnology, in recent years, there has been a considerable focus on cyanobacteria as a nitrogen fixer prokaryote capable of carrying out photosynthesis# due to the high lipid content present in their thylakoid membranes, cyanobacteria have a considerable potential to be used as a source of raw material in third generation biofuels# the present study was undertaken to characterize the autotrophic growth of anabaena vaginicola (a# vaginicola) as the cyanobacterium under different concentrations of sodium nitrate# nano3 is the main source of nitrogen in bg-11 medium for autotrophic growth of cyanobacteria# by changing the concentration of nano3 in the formulation of bg-11 medium, it was found that growth rate constants of the cultures with different initial concentrations of nano3 differed significantly from each other, suggesting that the initial nano3 concentrations in bg-11 medium can have considerable effects on the growth of a# vaginicola# absorbance readings for a# vaginicola culture grown in bg-11 media containing 1#875 and 2#25 g/l nano3 were highest among seven groups of cultures and expressed highest specific growth rate (0#386 and 0#408 day-1, respectively)# bg-11 medium prepared with nano3 at the lower level than the original amount of this inorganic salt (25% of 1#5 g/l) was not able to fully support the growth of a# vaginicola culture and the longer exponential phase of growth was with the lower rate constant (0#191 day-1)# this growth rate in comparison with the growth in the nitrate-free bg-11 medium (bg-110) was also lower#