R. arrhizus's biomass assessment using XTT in the presence of 0 (control), 80, 160, 320 and 640 ng/ml for DEXA (A), HC (B), MPN (C) under 5% CO2 atmosphere in RPMI, YNB and YAG. No promotion of growth was observed (P value > 0.05, t Student non parametric test).