Strain improvement of predacious fungi: In vitro screening of mutant strains for heavy metal tolerance

The effect of heavy metals (sodium arsenate, lead nitrate and mercuric chloride) at different concentrations (100, 200, 500, 1000 μM) on in vitro growth profiles of the mutant strains of Duddingtonia flagrans and Verticillium chlamydosporium were studied compared to those of controls (wild isolate). The study revealed no apparent inhibitory effect of sodium arsenate and lead nitrate on both the mutant strains of D. flagrans and V. chlamydosporium. Though inhibitory effect of mercuric chloride on mutant strains of both the fungal species could be observed, the mutant strains appeared to tolerate the presence mercury heavy metal to a considerable extent. The study revealed that the mutant strains of D. flagrans and V. chlamydospoirum could easily be deployed in the environment contaminated by industrial toxicants like arsenic lead and mercury.