Biodegradation of phenol by alginate immobilized Chlamydomonas reinhardtii cells

In the present work, the biodegradation of phenol by alginate immobilized Chlamydomonas reinhardtii cells was investigated. Immobilized Chlamydomonas reinhardtii could remove up to 1300 μmol/L of phenol within 10 days of cultivation. Metabolic activity was demonstrated by the extracellular release of catechol. Beads prepared at high concentrations of alginate (5-6% w/v) were found to protect microalgae against the strong inhibitory effects of phenol on the photosynthetic apparatus. Cells immobilized in beads of higher concentrations of alginate exhibited higher metabolic efficiencies compared to those prepared by lower alginate concentrations. Lower alginate concentrations (3-4% w/v) led to increased cell leakage, while the presence of phenol in the medium had the opposite effect in all alginate concentrations. Resuspension of immobilized microalgae in a medium containing a growth-promoting substrate, led to colony formation only on the external surface of alginate beads, indicating that acetic acid and consequently phenol, could not penetrate the internal of alginate beads. The significance of the work is that alginate immobilized Chlamydomonas substantially minimize the required volume of the aqueous medium and improve the economics and commercial application prospects of the process.