Enhanced Biodegradation of Methyl Orange Through Immobilization of Shewanella oneidensis MR-1 by Polyvinyl Alcohol and Sodium Alginate.

Shewanella oneidensis MR-1 has great potential for use in remediating azo dye pollution. Here, a new high-efficiency biodegradation method was developed utilizing S. oneidensis MR-1 immobilized by polyvinyl alcohol (PVA) and sodium alginate (SA). After determining the optimal immobilization conditions, the effects of various environmental factors on methyl orange (MO) degradation were analyzed. The biodegradation activity of the immobilized pellets was evaluated by analyzing the MO removal efficiency, and characterization was performed using scanning electron microscopy. The MO adsorption kinetics can be described using pseudo-second-order kinetics. Compared with free bacteria, the MO degradation rate of the immobilized S. oneidensis MR-1 increased from 41% to 92.6% after 21 days, suggesting that the immobilized bacteria performed substantially better and had more stable removal rates. These factors indicate the superiority of bacteria entrapment in addition to its easy application. This study demonstrates that the application of immobilized S. oneidensis MR-1 entrapped by PVA-SA can be used to establish a reactor with stable and high MO removal rates.