Feasibility of extracting arsenic from industrially polluted waters by the exploitation of two arsenic-tolerant fungi

Abstract

The ability of two fungi (Scopularlopsis brevlcaulis & Phaeolus schweinitzii) to accumulate arsenic (As) was investigated and the most tolerant species (S. brevicaulic) selected for further study, Growth on malt and Czapek-dox media was compared, together with the growth response to a change in medium concentration, pH .available light intensity, and the addition of arsenite, selenium, tellurium, and industrial effluent As. The maximum concentration (concn.) of arsenate tolerated by the fungus was defined. An ability to grow in petri dishes, shake flasks and a chemostat was tested, to determine the potential of this fungus for large scale production. Swab samples were taken from As contaminated, industrial areas to detect the presence of microorganisms. The potential uptake of As by mycelia growing in malt and floating on a 1 % glucose solution was monitored via the application of two As assays. Only mats of mycella floating on glucose exhibited a significant decline in medium As concn.. A third test was employed to determine the amount of As taken up by the mycella and showed more As present in fungi grown on malt than the floating oats. The use of this test to detect the volatile end product of As accumulation (trimethylarslne) did not yield any conclusive results. Extracellular or Intracellular enzymes Involved in the uptake and volatilisation of As could not be found. A change in mediumviscosity, associated with growth In the presence of As. was found to be linked to qualitative rather than quantitative changes in medium components, by the use of biochemical tests, microscopic investigation and polyacrlamide gel electrophoresis.