All over the world, the treatment of textile wastewater has become a significant problem due to the development of the textile industry. Particularly, the treatment of synthetic dyes, which are found abundantly amounts in textile wastewater, has gained importance. Recent studies have focused on the use of biological treatment technologies to remove pollutants in water. On the other hand, the disposal of wastes from biological treatment technologies was considered as another environmental problem. This study aims to compare the antimicrobial properties of the extract obtained from dye loaded and un-loaded lichen biomass after the biosorption process. According to the results of this study, it was found that the extract obtained from the waste lichen biomass, which has loaded with the textile dye in the decolorization process, showed a similar antimicrobial effect with the unloaded lichen extract. To sum up the waste lichen biomass used to remove textile dyes can be reused for the application of antimicrobial products.