Evaluation of Trichoderma isolates for their potential biosorption of copper (Cu) and iron (Fe) in Malnad (hilly) region of Karnataka state

The growing copper (Cu) and iron (Fe) toxic levels in the soils and the demand for environmentally safe, cost effective methods for reclamation metal toxic soils has been major priority in the Malnad (hilly) regions of Karnataka state. The present investigation was carried out using five best performing Trichoderma isolates against fusarium and sclerotium for their tolerance and biosorption levels of Cu and Fe. All the five Trichoderma isolates tested for their tolerance to Cu and Fe levels showed maximum growth at all concentrations. However, their biosorption levels are varied, atomic absorption spectrophotometer (AAS) analysis revealed that Trichoderma (Tr)-22 isolate absorbed higher concentrations Cu (4.10 ppm) and Fe (13.26 ppm) in dry mycelia from the total supplied Cu (6 ppm) and Fe (40 ppm). In a pot culture study, the maximum mean colony forming units (CFU’s) was recorded with Tr-22 at all the concentrations of Cu (4, 6 and 8 ppm) and Fe (30, 40 and 50 ppm) amended to the soil medium, followed by Tr-14 isolate. Phylogenitic analysis of tef 1 gene of Trichoderma isolates revealed that all the isolates clustered together with Tr-22 and Tr-29 are showed more genetic relatedness, isolate Tr-14 separated out into another sub-cluster.