Removal of arsenic by fungal strains of Fusarium

PELLIZZARI, ESTHER EDITH; BEDOGNI, GISELLE ROCIO; MONZON, EDGARDO HERNAN; GIMENEZ, MARÍA CECILIA

Beijing

Congreso; 7° International Congress on Arsenic in the Environment - Environmental Arsenic in a Changing World; 2018

Department of Soil Environmental Sciences. Research Center for Eco-Environmental Sciences. Chinese Academy of Sciences. P.R.CHINA

Our fundamental purpose is to improve the quality of water in the area in order to reduce exposure to arsenic of the resident population through the application of low cost methodologies to improve water quality in general. The objective of our study was to observe the different mechanism that can be performed by strains of the genus Fusarium, to develop bioassay systems of arsenic and other trace elements. Fusarium culture was performed on potato dextrose agar with different arsenic concentrations. The cultures were identified at the specie level on the basis of macroscopic and microscopic characteristics. Colony diameter for radial growth (cm) was measured during the incubation period. Slide extension were prepared with cotton blue lactophenol for the observation of hyphae, conidiophores and conidia, and examined under a Leica-DM2500 microscope in a 40x magnification. Pure cultures of common Fusarium were identified by comparing the phenotypic characteristic features of each fungi described in the Fungi and Food Spoilage (Pitt & Hocking, 2009). Phenotypic changes of Fusarium in the presence of arsenic were determined by sowing the strains in bengal rose agar formulated with stock solution of arsenic at 1, 5, 10, 20, 40, 50, 60 and 80 mgAs(V)/L respectively. For the study of the removal of arsenic, the Fusarium inoculate were prepared form a pure fungal culture of 15 days and inoculated in a system designed with natural air circulation, with a depth of 3 cm broth formulated with 0.5 % of sodium chloride, 1% glucose and 10 mgAs(V)/L, using sodium arsenate salt. The flotation of mycelium allowed draining the liquid of removal easily. The percentage of removal of arsenic by Fusarium oryzae was 90% in 15 days. In the growth of Fusarium with arsenic, phenotypic differences of the fungus were observed in comparison with the control culture and sexual sporulation is observed, produce by cellular stress. Fusarium oryzae was the only one that reached 60 mgAs(V)/L, being the most tolerant. The behaviour of different species of Fusarium with highly aggressive metabolism against arsenic has been observed, being Fusarium oryzae the one that showed best answer to the presence of arsenic. The results obtained allow us to deduce that Fusarium has a high capacity to remove arsenic and that this genus would be a very good organism to work with toxic metals.