PRELIMINARY TESTS IN VITRO OF BIOSORPTION CADMIUM BY NATIVE FUNGAL STRAINS OF CONTAMINATED SOIL

Abstract

Introduction: Heavy metals such as cadmium (Cd),can not be degraded by chemical or biological methods , and tend to bioaccumulate and biomagnify, are a serious problem in the food chain , cause a variety of toxic effects in all living organisms. In humans, it is considered that the direct source of acquisition of Cd, comes from food grown on soils contaminated by heavy metals. In agricultural soils, the presence of high levels of Cd is an environmental problem, because the Cd is mobile and plants absorb it easily, as in the crop´s cocoa (Theobroma cacao). Considering the potential of fungi to adapt and grow in contaminated soils, and their ability to biosorption of heavy metals, a method was proposed to initiate a series of tests in vitro, with the aim of selecting tolerant fungal strains, at increasing concentrations of Cd in liquid culture media. The tests were conducted at the Laboratory of Agro- Environmental Biotechnology Research ( LIIBAAM ) at the University of Santander , preliminary results are presented. Materials and methods: A totally random sampling was performed in soils contaminated by heavy metals mining region of California and agricultural soils of the crop´s cocoa region: El Carmen and San Vicente de Chucuri (Santander South - Colombia). We analyzed a total of 45 composite samples of the three study regions, for fungal isolation. Results: The genera Aspergillus and Trichoderma, showed high percentages of Cd biosorption, 98.6 % and 96 % respectively in liquid culture media. Conclusion: The tested methodology, was efficient for screening in vitro fungal strains with high capacity Cd biosorption in their biomass.