Effect of Cd on phosphate solubilizing abilities and hydrogen peroxide production of soil-borne micromycetes isolated from -rhizosphere

The aims of this work were to evaluate the phosphate-solubilization and hydrogen peroxide (HO) production by the soil-borne micromycetes, , isolated from rhizosphere and to study the effect of several concentrations of Cadmium (Cd) on both variables. Our results showed that   achieved a higher P-solubilization and HO production than   and  , as only   showed a positive correlation (R = 0.71) between P-solubilization and HO production. In dose–response assays,   was also more tolerant to Cd (0.31 mM) in comparison to   (0.26 mM). Analysis of the 2 factorial experimental design showed that P-solubilization by   was negatively affected by increases in Cd ( = 0.04) and yeast extract ( = 0.02) in the culture medium. The production of HO was positively affected only by glucose ( = 0.002). Fungal biomass production was reduced significantly ( = 0.0009) by Cd and increased ( = 0.0003) by high glucose concentration in the culture medium. The tolerance and correlation between P-solubilization and HO production in the presence of Cd was strain and species dependent. The effects of Cd, glucose, ammonium sulfate and yeast extract on those variables were evaluated through a two-level factorial design.   is promising for P-solubilization in soils contaminated with Cd and may be an alternative for manufacture of biofertilizers to replace chemical fertilizers.