Biodegradation and Detoxification of Low-Density Polyethylene (LDPE) by Stenotrophomonas sp. and Alcaligenaceae bacterium.

Every year, human activities introduce large amounts of synthetic plastics into the environment. Decomposition of the plastic derivatives is very difficult and time consuming, so it is essential to eliminate these pollutants using different methods. Bioremediation, is suitable option, because of the low cost and environmentally safe. In this research, degradation of low-density polyethylene (LDPE) was investigated by two strains, isolated from Hamadan province (Iran) landfill soil. After identification by 16sr DNA primers, their abilities of polyethylene biodegradation were examined by Fourier transform infrared (FTIR), SEM and Gas Chromatography-Mass Spectrometry (GC-MS). Using media contain polyethylene) after and before addition of bacteria), toxicity test was conducted by measuring the germination index, root and hypocotyl length of Lactuca sativa seed. After three months, 10.15% ± 1.04 weight loss of LDPE achieved through strain Stenotrophomonas sp. degradation. Both strains had high biofilm formation capacity, confirmed by Electron microscope images and FTIR analysis. GC-MS confirmed the presence of the end-product of LDPE degradation (Pentacosane, Hexacosane, and Octadecane). Both, Stenotrophomonas sp. and Alcaligenaceae bacterium had significant detoxification ability. In media contain LDPE (without bacteria), decrease in the germination of lettuce seeds was observed.

Removal of Phenol by A. belladonna L. Hairy Root.

Phenolic compounds that present in the several industries are harmful and dangerous for human health. In this study we have studied the potential of Atropa belladonna hairy roots in phenol removal of wastewater. The optimal conditions for the removal process were evaluated using different phenol (10-500 mg.1(-1)) and H2O2 (1-15 Mm) concentrations. In the presence of H2O2, Roots were able to remove phenol concentrations up to 500 mg.1(-1). in the wide range of pH (4-9), reaching high removal efficiency. When roots were re-used for five consecutive cycles, phenol removal efficiency decreased from 98-62%, in the last cycle. After the removal process, the solutions were obtained from the experiment were estimated for their toxicity using a test with Lactaca sativa L. seeds. Results showed that the treated solution was less toxic than the parent solution.