Degradation of phenol at high concentrations using immobilization of Pseudomonas putida P53 into sawdust entrapped in sodium-alginate beads

Phenols are distributed either as natural or artificial mono-aromatic compounds in various environmental sites as major pollutants. The objective of this study was the immobilization of the phenol degrading bacteria P. putida P53 and A. scleromae P69 in sodium-alginate beads and sawdust as carriers and evaluate the biodegradation ability. The biodegradation ability of strains in free form were evaluated and P. putida P53 was shown to biodegrade up to 1,800 mg/L phenol. Bacterial biomass was prepared and attached to carrier with entrapment and attachment methods. Prepared beads were added to Erlenmeyer flasks containing different concentrations of phenol in BH medium (1,800, 2,200, 2,600 and 3,000 mg/L). According to the results, phenol biodegradation efficiency of immobilized bacteria in sawdust was more than free form. Strain P53 had better biodegradation than P69 strain. Attachment and entrapments into carriers had positive results, Scanning electron micrograph (SEM) images indicated that alginate beads were globular shapes (10 nm), and strains aggregated between the large cavities of the matrix. Comparison of sawdust and alginate as carriers for degradation of phenol at high concentrations demonstrated that sawdust improved biodegradation better, and immobilized P53 into sawdust entrapped in sodium-alginate beads can be used for biodegradation purposes.