Melanins from the Lichens Lobaria pulmonaria and Lobaria retigera as Eco-Friendly Adsorbents of Synthetic Dyes

Synthetic dyes are widely used in the industry; they are chemically stable, difficult to neutralize, and therefore they are a threat to the environment when released into wastewaters. The dyes have a significant impact on plant performance by impairing photosynthesis, inhibiting growth, and entering the food chain and may finally result in the toxicity, mutagenicity and carcinogenicity of food products. Implementation of the dark piment melanin for the adsorption of the synthetic dyes is a new ecologically friendly approach for bioremediation. The aim of the present work was to study the physico-chemical characteristics of melanins from the lichens Lobaria pulmonaria and Lobaria retigera, analyze their adsorption/desorption capacities towards synthetic dyes, and assess the capacity of melanins to mitigate toxicity of the dyes for a common soil bacterium Bacillus subtilis. Unique chelating properties of melanins determine the perspectives of the use of these high molecular weight polymers for detoxification of xenobiotics.