Treatment of sugarcane vinasse using an autochthonous fungus from the northwest of Argentina and its potential application in fertigation practices

Vinasse, the most important liquid residue of the bioethanol production, is often used in fertigation programs. However, this practice may have negative effects on crops if applied without a prior conditioning treatment. In the present study, the efficiency of a fungus-based process as a method for vinasse treatment was evaluated. Phytotoxicity of the residue, before and after biological treatment, was tested on two plant species used for human consumption (Triticum aestivum L. and Raphanus sativus) in order to evaluate the application of vinasse in fertigation. The fungus, identified as Aspergillus sp. V2, showed high tolerance to vinasse, resulting in an optimal growth even when is cultivated on the undiluted residue. Biologically treated vinasse with a cycle of re-inoculation of spores resulted in a COD removal of 52%, whereas pH was increased from 4.4 to 6.1 at the end of treatment. Toxicity studies demonstrated a substantial improvement in the growth parameters (vigor index and fresh weight) of plant species exposed to treated vinasse compared to those exposed to raw residue. These results show that Aspergillus sp. V2 is useful for the recovery of an actual wastewater like sugarcane vinasse, enhancing its fertilizing properties.