Jornal de Biorremediação e Biodegradação

Abstrato

Isolation and Characterization of Relevant Algal and Bacterial Strains from Egyptian Environment for Potential Use in Photosynthetically Aerated Wastewater Treatment

Marwa El Rakaiby, Tamer Essam and Abdelgawad Hashem

A number of environmental samples were collected from different locations in Egypt. Briefly, 9 bacterial strains and 4 algal strains were isolated and characterized. All isolated bacterial strains showed a remarkable ability to tolerate and/or biodegrade phenol (aromatic pollutant) and pyridine (hetero-aromatic pollutant). Phenol showed higher toxicity than pyridine to both bacterial and algal isolates. The bacterial isolates were identified as members of Pseudomonas, Chryseomonas, Sphingomonas and Burkholderiae species. The highest biodegradation rate and capacity were reported to bacterial isolate M4, identified as Pseudomonas MT1. This strain was able to degrade up to 1700 and 3000 mg l^-1 of phenol and pyridine respectively. Pseudomonas MT1 showed the highest phenol biodegradation rate of 29 mg h^-1 and lag phase approximately of 8 h and was optimally grown on 1000 -1250 mg phenol l^-1. All algal isolates were morphologically identified as members of the Chlorella genus. None of the isolated algal strains showed biodegradation ability of any of the tested organic pollutants. However, isolates A1, A2 and A4 showed remarkable tolerance to both phenol and/or pyridine. The highest tolerance capacity was reported to algal isolate A4, identified as Chlorella vulgaris MM1 with a toxicity cut off of 500 and 1000 mg l^-1 of phenol and pyridine respectively. Both Pseudomonas MT1 and Chlorella vulgaris MM1 had no inhibitory effect on each other. Therefore, they represented potential candidates for the construction of algal bacterial microcosm used for the photosynthetically aerated biological degradation of effluents loaded with various organic pollutants.