Copper removal by polymer immobilised Rhizopus oryzae

Rhizopus oryzae, strain IMI 057412, was immobilised by inclusion in six different polymers: polyvinlformal, polysulfone, polyurethane, alginate, polyacrylamide, k-carrageenan, polyethyleneimina(PEI). It was also grown on a seventh, polyurethane. The biomass/polymer matrices were formed into equal size units (4 mm spheres or cubes) and the resulting biomass/polymer matrices were used to uptake copper at 2 mg/l from a laboratory-formulated copper solution in shake flask experiments at room temperature and initially neutral pH. Results showed that the copper uptake capacity of immobilised biomass was either equal to or less than that of free biomass. Biomass immobilised in polyurethane gave a capacity equal to that of free biomass, while other matrices hindered the uptake to different degrees. The k-carrageenan matrix proved to be unstable in the copper solution and dissolved during the experiment releasing the biomass and leading to an erroneous result. The polymer matrices without biomass, with the exception of alginate and polysulfone, showed no measurable copper adsorption capacity. All the experiments were conducted in duplicate with a maximum variation between them of 7%.