Influence of medium buffers on growth of the cyanobacterium Anabaena variabilis AVM13

In attempts to optimize culturing conditions, the interference of various buffers used during growth of Anabaena variabilis (AVM13 – hupmutant strain) on H2 photoproduction has been studied. The present work describes the influence of four different buffers upon growth of the A. variabilis: Glycylglycine Gly (5 mM), (N[2-Hydroxyethyl]piperazine-N -[2-ethanesulfonic acid] HEPES (10 mM), N-tris[Hydroxymethyl]methyl-2-aminoethane-sulfonic acid TES (10 mM) and Tris(hydroxymethyl)aminomethane hydrochloride Tris-HCl (6.35 mM), as compared with no buffer at all (Control Ctrl). The buffer that presented the best performance in terms of growth rate in the exponential phase (obtained under appropriate growth conditions) and pH stability, was further tested at several concentrations, with the goal of reducing processing costs and avoid possible interferences on A. variabilis growth. OBJECTIVES A. Catarina Guedes , Cristina M. Monteiro , Luis A. Meireles , Katrin Mullner b and F. Xavier Malcata a