DETOXIFICATION AND DECOLOURISATION OF SYNTHETIC TEXTILE EFFLUENT BY A MICROBIAL CONSORTIUM ASSOCIATED WITH MARINE ENVIRONMENTS

The textile industry produces large amounts of effluents, containing dyes and salts at an alkaline pH. These effluents must be treated before being dumped into water bodies, otherwise they will be in contact with the aquatic fauna and flora. With this in mind, bioremediation using white-rot fungi and bacteria has been a sustainable alternative for the treatment of these pollutants. Therefore, if microorganisms are tolerant to saline environments with alkaline pH, they could be adapted to the textile effluent conditions. The aim of this study was to evaluate the potential of microorganisms recovered from marine environments in the detoxification and decolourisation of a synthetic textile effluent. The white-rot fungus Marasmiellus sp. CBMAI 1062 and the bacteria Bacillus subtilis CBMAI 707 and Dietzia maris CBMAI 705 were used. The synthetic textile effluent was composed of three dyes (Reactive Blue 200mg/L, Indigo Blue 200mg/L and Black Sulfur 200mg/L), NaCl 30g/L, malt extract 3g/L and pH 8.0. Two different strategies were used. Firstly, the fungus was added in the effluent for 7 days and after this period the bacteria were added separately and together for another 2 days. In the second strategy, the bacteria were added separately and together for 2 days in the effluent and then the fungus was added for another 7 days. At the end of the experiment, dry biomass, percentage of decolourisation and the percentage of detoxification (inhibition of the growth of Cucumis sativus) were analyzed. The results showed that on the first strategy, dry biomass was higher than that ones obtained in the second strategy. In addition, the highest percentage of decolourisation (30.32%) was observed in the experiment using the fungus initially and the two bacteria subsequently. Regarding the detoxification experiment, a decrease in percent inhibition was observed in the assays using Bacillus sp. first (71%), Bacillus sp. and Dietzia sp. first (71%) and Bacillus sp. and Dietzia sp. after 7 days with the fungus (72%), compared with the non-treated effluent (84%). The microbial consortium, as used in the first strategy, formed by Marasmiellus sp. and by the bacteria Bacillus sp. and Dietzia sp. presented the highest values of decolourisation and a significant detoxification. Results from the present study highlight the relevance of marine-derived microorganisms for bioremediation of saline processes/environments.