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Abstract In the bioethanol industry and its derivative processes, 9–14 l of vinasse per liter of ethanol are obtained as residue, depending on whether or not a recirculation process is used. If the vinasse is discharged directly into water bodies without proper treatment it can produce negative effects on existing biota and on human health. The main objective of this study was to evaluate the capacity of a mixed treatment with Komagataeibacter kakiaceti GM5 and Trametes versicolor DSM 3086 to degrade and reduce the toxicity of this by-product. In order to carry out the tests, an experimental culture media of vinasse at 60% (v/v) was used. This culture was compared to a standard medium of glucose at 2% and, simultaneously, a mixed culture (bacterium-fungus) was used through a batch process in an orbital shaker. When compared to the treatments evaluated with individually grown microorganisms, the mixed treatment proposed produced the best COD results in vinasse degradation. However, better results were obtained when using the treatment with T. versicolor DSM 3086 for color removal and treatment with K. kakiaceti GM5 produced better results in terms of turbidity and toxicity. Although the simultaneous mixed treatment did not improve all the variables studied, it never showed the lowest performance. Therefore, this proposal can be considered as an innovative biological alternative in degradation processes of great organic pollutants such as vinasse. Graphical abstract fx1 Highlights • The vinasse diluted to 60% (v/v), was considered as the optimal concentration. • The mix treatment presented the best degradation of vinasse in terms of COD. • K. kakiaceti GM5 was able to decrease the acute toxicity up to 11.9%. • The mixed treatment presents a novel alternative for the degradation of the vinasse. [ABSTRACT FROM AUTHOR]

In the bioethanol industry, per liter of the produced alcohol 9 to 14 liters of vinasse are obtained as a byproduct. If the vinasse is directly shed into bodies of water without an adequate treatment, it may have negative effects on the existing biota and human health due to its high turbidity and color, low pH and high content of organic material. The purpose of this study was to assess the acute toxicity of vinasse by means of a rapid test with Aliivibrio fischeri and compare it with a standard immobilization assay with Daphnia magna . The standard assay of D. magna by means of its EC 50 of 4.7% showed that organism was more sensitive to the contaminant, in comparison with the 69.6% obtained with the A. fischeri which suggests that it should be continuesly used as one of the organisms of first choice for the evaluation of the acute toxicity of this effluent., (Copyright © 2019 SETOX & Institute of Experimental Pharmacology and Toxicology, SASc.)