Resistance and uptake of cadmium by yeast, Pichia hampshirensis 4Aer, isolated from industrial effluent and its potential use in decontamination of wastewater.

Pichia hampshirensis 4Aer is first ever used yeast for the bioremediation of environmental cadmium (Cd(+2)) which could maximally remove 22 mM/g and 28 mM/g Cd(+2) from aqueous medium at lab and large scales, respectively. The biosorption was found to be the function of temperature, pH of solution, initial Cd(+2) concentration and biomass dosage. Competitive biosorption was investigated in binary and multi-metal system which indicated the decrease in Cd(+2) biosorption with increasing the competitive metal ions attributed to their higher electronegativity and larger radius. FTIR analysis revealed the active participation of amide and carbonyl moieties in Cd(+2) adsorption confirmed by EDX analysis. Electron micrographs summoned further surface adsorption and increased cell size due to intracellular Cd(+2) accumulation. Cd(+2) was the causative agent of some metal binding proteins as well as prodigious increase in glutathione and other non-protein thiols levels which is the crucial for the yeast to thrive oxidative stress generated by Cd(+2). Our experimental data were consistent with Langmuir as well as Freundlich isotherm models. The yeast obeyed pseudo second order kinetic model which makes it an effective biosorbent for Cd(+2). High bioremediation potential and spontaneity and feasibility of the process make P. hampshirensis 4Aer an impending foundation for green chemistry to exterminate environmental Cd(+2).