Evaluation of potential use of immobilized Penicillium griseofulvum in bioremoval of copper

摘要

Biomass of spent P. griseofulvum was immobilized with various immobilizing agents. Among the different immobilizing materials screened, entrapment of cells in a naturally occurring protein with glutaraldehyde showed most favourable results for copper recovery. Entrapped cells of P. griseofulvum were successfully used even after 8 cycles of copper sorption. Glutaraldehyde concentration of 2 percent in the system and contact time of 60 minutes functioned ideally for optimum copper sorption. Presence of 10 ml of natural protein as compared to 5 ml in the immobilized system increased the copper removal by 1,3 fold. Both, blank beads and immobilized biomass proved efficient to recover the copper from solutions having low copper concentration. When blank beads, immobilized biomass and free biomass were repeatedly charged with copper bearing solution, after 8 cycles, immobilized biomass showed nearly 71 fold higher copper removal as compared to blank heads and 1.5 fold higher than free biomass. Under the experimental conditions immobilized system showed as high as 20.47 mg.g~(-1) copper loading as opposed to 15.51 mg.g~(-1) by free biomass. Challenging the system with high copper concentration of 63.5 ug.ml~(-1) (total 50.80 mg) showed 19, 56 and 44 percent copper removal with blank beads, immobilized biomass and free biomass respectively. Free biomass reached saturation point with 38.10 mg of copper charging. Blank beads showed diphasic mode after 4~(th) cycle. In the initial 2 to 3 cycles, free biomass sorbed more copper as compared to immobilized biomass. Alter 3 cycles immobilized biomass showed significant positive difference in copper sorption. In the 6~(th) cycle immobilized biomass gave 13 times more copper removal as compared to free biomass. Depending on the cycles of copper charging, the percent copper removal ranged from 2.3 to 94.0. The immobilized P.griseofulvum cells performed quantitative copper removal both from pure copper solution as well as from industrial effluent.