Antarctic yeast Cryptococcus laurentii (AL65): biomass and exopolysaccharide production and biosorption of metals

Abstract

AbstractBACKGROUNDPollution by heavy metals poses serious environmental problems and is dangerous to human health, so considerable attention has been given to methods for their removal from industrial effluents. The need for highly effective biosorbents able to remove heavy metals from waste waters, even at the low concentrations which are still toxic for living organisms in ecosystems, is a topical problem.RESULTSIn the present study, psychrophilic yeast strain Cryptococcus laurentii (AL65) was used to explore its potential for biosorption of metal ions. The accumulation of biomass was followed continuously in the context of bioreactor cultivation. An adsorption experiment of caustic pretreated biomass was conducted in batch mode with synthetic mixed solution in the pH range 4.7–7.0, and ion concentrations of individual metals were simultaneously determined by inductively coupled plasma ‐ optical emission spectrometry (ICP‐OES). Biosorption abilities were determined for 15 elements: the total amount of adsorbed ions was 68 mg g−1 dry biomass for 10 mg L−1 initial concentration of each element in the solution, and 113 mg g−1 for 20 mg L−1. The highest adsorption capacity was observed in the 20 mg L−1 solution for aluminium, chromium, indium, gallium, iron and bismuth in the range 12–16 mg g−1 dry biomass at an optimal pH of ≈5.CONCLUSIONThe results on the biosorption ability of Antarctic producer Cryptococcus laurentii (AL65) can be used in the optimization of technological processes for the removal of heavy metals from aqueous solutions. © 2019 Society of Chemical Industry