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

Abstract

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.

Topography of UV-Melanized Thalli of Lobaria pulmonaria (L.) Hoffm

“…The list of enzymes, their specific activity, corresponding buffers and concentrations are presented in Table 1 . After treatment of pale and melanized thalli with enzymes, the absorbance of the incubation solutions was analyzed at a wavelength of 490 nm ( Figure 4 A,B), which corresponds to the absorbance of melanins [ 22 ] and some other phenolic compounds such as quinones [ 30 ]. After treatment of thalli with chitinase, lichenase, endoglucanase, and pectinase, the absorbance of incubation solutions was low, and there was no difference between pale and melanized thalli.…”

“…This is likely a result of the complexity of the anatomical structure of the lichen thallus, the interactions between the fungal and photosynthetic symbionts, and the diversity of metabolite biosynthesis pathways that occur in lichens. Furthermore, lichen melanins can form complexes with metals and the elements of lichen cell walls, making them difficult to study [ 6 , 22 ]. Previous studies on melanin complexes isolated from two lichen species used infrared (IR) spectroscopy to reveal the presence of aromatic and aliphatic functional groups [ 23 ].…”

Fabrication of Monodisperse Magnetic Polystyrene Mesoporous Composite Microspheres for High-Efficiency Selective Adsorption and Rapid Separation of Cationic Dyes in Textile Industry Wastewater

“…3,4 Apart from causing severe water pollution, they can transmit adverse health effects, ranging from dizziness and nausea to jaundice and even cancer, through the food chain. 5 Addressing the characteristics and discharge requirements of dye wastewater, the selection of appropriate treatment methods is crucial. These methods include coagulation filtration, 6 chemical oxidation, 7 biodegradation, etc.…”

“…Dyes are common wastewater pollutants in the textile industry, encompassing organic pollutants like amines, pyridines, phenols, and benzidine . These complex wastewaters, characterized by high chromaticity and toxicity, pose challenges for biodegradation and decolorization. , Apart from causing severe water pollution, they can transmit adverse health effects, ranging from dizziness and nausea to jaundice and even cancer, through the food chain . Addressing the characteristics and discharge requirements of dye wastewater, the selection of appropriate treatment methods is crucial.…”

Steric and Energetic Studies on the Synergetic Enhancement Effect of Integrated Polyaniline on the Adsorption Properties of Toxic Basic and Acidic Dyes by Polyaniline/Zeolite-A Composite

“…However, the majority of frequently used dyes have chemical characteristics that are both poisonous and very resistant to biodegradation [4,5]. Environmentally, the presence of these types of synthetic organic compounds in water systems significantly impairs both the bioactivity and photosynthetic activity of aquatic species by obstructing the effectiveness of sunlight's penetration [6,7].…”