Mechanism of metal ion biosorption by fungal biomass

Abstract

Alkali extracted mycelial biomass from Aspergiilus niger, referred to as Biosorb, was found to sequester metal ions (Cd z § Cu z § Zn z § Ni 2 § and Co z § efficiently both from dilute and concentrated solutions upto 10% of its weight (w/w). Sequestration of metal ions from a mixture was also efficient but with attendant antagonisms. The kinetics of metal binding by Biosorb indicated that it is a rapid process and about 70-80% of the metal is removed from solution in 5 min followed by a slower rate. The mechanism of metal binding is shown to be due to exchange of calcium and magnesium ions of the Biosorb during which equimolar concentrations of both the ions were released into the medium. Following this an efficient procedure for the regeneration and reuse of Biosorb was standardized by washing the biosorbent with calcium and magnesium solution (0.1 M). Biosorbents prepared from Neurospora, Fusarium and Penicillium also exhibited similar mechanisms for metal ion binding, though they had a lower metal binding capacity when compared with Biosorb. Chemical modification of carboxylic acid functional groups of the Biosorb resulted in loss of 90% of metal binding capacity which could not be restored even on regeneration. The significance of this finding on the metal sequestration mechanisms of microbial biosorbents is discussed.

Biosorption of Cadmium from Aqueous Solutions Using A local Fungus Aspergillus cristatus (Glaucus Group)

“…The change in the position and intensity of the peaks especially in the region range 3200 to 3500 cm -1 can be attributed to complexation of the functional groups of the fungus, which resulted from hydrolyzing of some polysaccharides on the cell wall to shorter saccharides such as oligosaccharides, dioses and monoses.Similar results were obtained by (Rao et al, 2005 andAkthar et al, 1996).…”

Lead biosorption onto waste beer yeast by-product, a means to decontaminate effluent generated from battery manufacturing industry

“…Jianlong (2002) has reported similar reduction in biosorption of copper by HCHO-modified S. cerevisiae. Copper biosorption has been reported to be affected due to modification of carboxyl group present in the cell wall of Aspergillus niger (Akthar et al 1996).…”

Characteristic features of Bacillus cereus cell surfaces with biosorption of Pb(II) ions by AFM and FT-IR

“…Natural waters can easily be polluted by metal ions as a result of their release by industrial plants or mining activities [9][10][11][12]. The interactions between microorganisms and metals in water have attracted a significant attention in recent years [13][14][15][16][17][18][19][20][21]. In order to explain the biological phenomenon, researchers have applied different kinds of chemical and physical ways to investigate the interactions between the biomass and the heavy metals, such as potentiometric and conductomet- * Corresponding author.…”