Effect of Glucose Utilization on Nitrite Excretion by the Unicellular Cyanobacterium Synechocystis sp. Strain PCC 6803.
Up to 1 mM nitrite was excreted by Synechocystis strain 6803 cells growing under mixotrophic or photoheterotrophic conditions. This excretion is not due to a lower ratio of nitrite and nitrate reductase activities in the presence of glucose but seems to be related to a shortage of reduced ferredoxin, their electron donor, as a result of a decrease in noncyclic photosynthetic flow observed under these circumstances. Because about 60% of the reduced nitrate is excreted, the potential utilization of cyanobacteria for removal of nitrate from contaminated waters containing high concentrations of organic compounds is questioned.
Reyes
J C
JC
Departamento de Bioquímica Vegetal y Biología Molecular, Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla y Consejo Superior de Investigaciones Científicas, Apartado 1113, 41080-Seville, Spain.
Chávez
S
S
Muro-Pastor
M I
MI
Candau
P
P
Florencio
F J
FJ