Influence of dyes on metal removal: a study using live and dead cells of penicillium simplicissimum in single-metal and dye-metal mixtures

The metal removal efficiency of live and dead fungal cells of Penicillium simplicissimum (isolate 10, KP713758) was tested against 100 ppm toxic metals Cd, Cu, Pb, Zn and trivalent Cr in single-metal solutions and in mixtures with 50 ppm triphenylmethane (TPM) dyes (Cotton Blue, Crystal Violet, Methyl Violet, and Malachite Green). Results revealed that live cells were more effective at removing metals from single (10.8–70.0%) and dye-metal mixtures (5.3–62.2%) than dead cells (5.1–27.4%). The dyes in dye-metal mixtures influenced metal uptake capacity. All four dyes inhibited the uptake of Cd (0.9–7.1%), Zn (5.3–7.7%), Cu (5.0–25.8%) and Cr (47.3–60.7%) by live cells. The exception was the enhance removal of Pb by live cells (48.6 to 56.3–62.2%) in the presence of dye (MG or CB). Pb uptake was not affected by MV (51.8%), but was inhibited by CV (31.9%). For dead cells, uptake of metals (Cd, Cr and Zn) in single (3.2–27.4%) and dye-metal solutions (0.7–27.4%) was similar, whilst removal of Cu (6.4–13.5%) and Pb (33.6–44.0%) was inhibited by all four dyes. P. simplicissimum is concluded to have potential to remove toxic metals even in the presence of TPM dyes, with preferred use of live cells than dead cells.