Bioprospection of native microorganisms with bio-remediating capacity of soils contaminated by herbicides

Abstract

Organic farming has grown considerably in the wake of decrease in the use of chemical fertilizers. However, in contaminated areas its development is vetoed, and a long period of decontamination is necessary. A method to speed up the process is the use of bioremediation, or rather, the use of living microorganisms, in the degradation of pesticides. Current study aims at isolating microorganisms with bio-remediator potential of soils contaminated by three herbicides, and the effect of the herbicides on soil microorganisms. Tests were conducted to determine CO2 emission by soil biological activity. The effect of contaminants under the microbial population was evaluated by determining Shannon, Simpson and Pielou indexes. The potential of isolates as bioremediating agents was determined by the evaluation of the growth capacity of microorganisms in contaminated liquid BDA medium. Thirty-two microorganisms, 18 bacteria and 14 fungi, were isolated. Six fungal isolates and six bacterial isolates were used. The fungal isolate UERGS-FNI6 demonstrated great capacity to develop in liquid medium contaminated with glyphosate and atrazine, and its growth stimulated in both situations. The same was done for fungal isolates UERGS-FNI4 and UERGS-FNI1, which also had their development stimulated by atrazine and glyphosate, respectively. In the case of bacterial isolates, UERGS-BNI3 showed satisfactory growth in liquid medium contaminated by Imazetapir, showing to be resistant to this contaminant, and with potential for use as bio-remediators of soils contaminated with herbicides.