Environmental pollution is one of the major concerns in the 21st century; where billions of tonnes of harmful chemicals are produced by industries such as petroleum, paints, food, rubber, and plastic. Phenol and its derivatives infiltrate the ecosystems and has become one of the top major pollutants worldwide. This review covers the major aspects of immobilization of phenol-degrading bacteria as a method to improve phenol bioremediation. The use of various forms of immobilization matrices is discussed along with the advantages and disadvantages of each of the immobilization matrices especially when environmental usage is warranted. To be used as a bioremediation tool, immobilized system must not only be effective, but the matrices must be non-toxic, non-polluting and if possible non-biodegradable. The mechanical, biological and chemical stability of the system is paramount for long term activity as well as price is an important factor when very large scale is concern. The system must also be able to tolerate high concentration of other toxicants especially heavy metals that form as co-contaminants, and most immobilized systems are geared towards this last aspect as immobilization generally provides protection from other contaminants.

Phenol removal via cellular immobilization: A review

Microorganisms are capable of degrading xenobiotic compounds such as phenol, producing innocuous end products. In the present study a bacterium, Pseudomonas resinovorans was investigated for its ability to grow and degrade phenol as sole source of carbon and energy. Experiments were also carried out with established phenol degrading microbes to draw a comparison study of the biodegradation potential under same physiological conditions. The biodegradation assays were performed in liquid medium with phenol as single substrate, with initial concentration of phenol ranging from 100 to 1000 ppm. With higher initial phenol concentration the lag phase and degradation time has been found to increase. It is found that Pseudomonas resinovorans is able to degrade phenol up to 750ppm in 120 hrs as free cell and 1000ppm of phenol in 60 hrs when immobilized in the calcium alginate beads. The higher concentration of phenol is lethal to microbe. Pseudomonas putida has been found to be the most efficient phenol degrading one over the others with degradation time of 144hrs for initial phenol concentration of 1000 ppm while it is able to degrade 750 PPM of phenol in 132 hrs. Pseudomonas resinovorans shows better degradation potential than Pseudomonas putida & Pseudomonas aeruginosa until the initial phenol concentration of the contamination is 750 PPM. Increasing the initial substrate concentration from 750 PPM inhibits the growth of the microbe. Result from this study indicates that the microbe can be used for the treatment of the phenol contaminated industrial waste water.

http://dspace.nitrkl.ac.in:8080/dspace/bitstream/2080/1581/1/ICER%202011.pdf

S S Mohanty

Papers

Comparative Study of the Phenol Biodegradation Potential of Free Cells and Immobilized Pseudomonas Resinovorans