Fig. 3.

Effect of different concentrations of ferrous sulfate on the factors affecting magnetosome production by M. gryphiswaldense MSR-1 during culture in optimized flask medium (OFM; 50 h). (A) Cell growth, (B) Cmag, (C) iron uptake, and (D) the magnetosome production. The maximum rate of cell growth in the concentration of 150 μM (A) and the maximum rates of Cmag, iron uptake, and magnetosome production were obtained in the presence of 200 μM ferrous sulfate (B, C, and D). The optimum concentration of ferrous sulfate for the highest magnetosome production yield was determined to be 150 to 200 μM. At these concentrations, the magnetosome production was 62% more than the initial condition (D) (p < 0.01).