Evaluation of a mixed simultaneous vinasse degradation treatment using Komagataeibacter kakiaceti GM5 and Trametes versicolor DSM 3086.

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.

Geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples, and its possible relationship with the prevalence of enamel fluorosis in children in four municipalities of the department of Huila (Colombia).

Fluoride is an element that affects teeth and bone formation in animals and humans. Though the use of systemic fluoride is an evidence-based caries preventive measure, excessive ingestion can impair tooth development, mainly the mineralization of tooth enamel, leading to a condition known as enamel fluorosis. In this study, we investigated the geochemical characterization of fluoride in water, table salt, active sediment, rock and soil samples in four endemic enamel fluorosis sentinel municipalities of the department of Huila, Colombia (Pitalito, Altamira, El Agrado and Rivera), and its possible relationship with the prevalence of enamel fluorosis in children. The concentration of fluoride in drinking water, table salt, active sediment, rock, and soil was evaluated by means of an ion selective electrode and the geochemical analyses were performed using X-ray fluorescence. Geochemical analysis revealed fluoride concentrations under 15 mg/kg in active sediment, rock and soil samples, not indicative of a significant delivery to the watersheds studied. The concentration of fluoride in table salt was found to be under the inferior limit (less than 180 µg/g) established by the Colombian regulations. Likewise, exposure doses for fluoride water intake did not exceed the recommended total dose for all ages from 6 months. Although the evidence does not point out at rocks, soils, fluoride-bearing minerals, fluoridated salt and water, the hypothesis of these elements as responsible of the current prevalence of enamel fluorosis cannot be discarded since, aqueducts might have undergone significant changes overtime.

Bioremediation techniques applied to aqueous media contaminated with mercury.

In recent years, the environmental and human health impacts of mercury contamination have driven the search for alternative, eco-efficient techniques different from the traditional physicochemical methods for treating this metal. One of these alternative processes is bioremediation. A comprehensive analysis of the different variables that can affect this process is presented. It focuses on determining the effectiveness of different techniques of bioremediation, with a specific consideration of three variables: the removal percentage, time needed for bioremediation and initial concentration of mercury to be treated in an aqueous medium.

Cellulose production by Gluconacetobacter kakiaceti GM5 in two batch process using vinasse as culture media.

The present study was conducted to evaluate the cellulose production by Gluconacetobacter kakiaceti GM5 by means of two aerobic treatments: the static discontinuous fermentation process (treatment 1) and the discontinuous fermentation process in a rotary shaker (treatment 2). All these experiments were carried out using vinasse as experimental culture media (VM) and were compared with standard media containing glucose at 2% (standard medium (SM)). A sample of each treatment was extracted every 24 h over a period of 168 h. The maximum rates of cellulose produced in treatment 1 using SM added up to 3.63 ± 0.18 g l(-1), and to 4.15 ± 0.16 g l(-1) when VM was used. The amount of cellulose produced in treatment 2 using SM was 2.95 ± 0.09 g l(-1) (which suggests an increase of 37%), and added up to 1.84 ± 0.07 g l(-1) when using VM. A better global yield of both treatments in terms of sugar consumption after 168 h was obtained when using VM: 32% in treatment 1, whereas in treatment 2 it was 9%. A 20% decrease on vinasse COD (Chemical Oxygen Demand) values was found to be yet another important advantage of working with this strain.

Evaluation of acute toxicity of vinasse by means of Daphnia magna and Aliivibrio fischeri: a comparative study.

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 EC50 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.