Lozova O. Yeasts - sorbents of some heavy metals ions.

The thesis is devoted to study the sorption abilities of yeast of the various taxonomical groups in relation to copper, lead and hexavalent chromium ions, research of their stability and growth at high concentration of heavy metals ions in medium, definition of biosorption ability by estimation of the experimental sorption isotherms. An agar-screening method (our modification of Thomas Pumpel method) was developed for more effective and rapid isolation of heavy metal-accumulating yeasts. According the agar-plate screening data among 113 yeast strains were selected 7 potential sorbent-strains Rhodotorula mucilaginosa 1776, Rh. aurantiaca 1195, Rhodotorula sp.4, Williopsis californica 248, Candida krusei 61т, Saccharomyces cerevisiae 1968, Cryptococcus sp. WT. It was determined their stability to high concentration (up to 750 mg/l) of heavy metals ions in medium. The yeast physiologies of growth and pH changes were studied in medium with heavy metal ions. The optimal conditions for realization of biosorption experiments were established. The levels of maximal sorption ability and biomass affinity to heavy metal ions were established by experimentally received sorption isotherms with mathematical modeling of biosorption process separately for everyone researched yeast strain. Received results allow recommending the most active yeast strains C. krusei 61т, Rh. aurantiaca 1195, Rhodotorula sp. 4, Cryptococcus sp. WT and W. californica 248 that can sorbs ions of copper, lead and chromium for introduction in new biotechnologies waste waters clearing from pollution with these metals and receiving them from different solutions.