Enhancing Bioremediation with Enzymatic Processes: A Review

The use of extracellular enzymes has been standard in many industries for many years; only recently have they been studied as a means for enhancing bioremediation. Extracellular enzymes are either secreted from organisms such as white rot fungi or are produced during a fermentation process and possess the ability to break down bonds within organic compounds and/or catalyze their transformation into less toxic and more biodegradable forms. Unlike many microbes, enzymes remain effective in a wide range of pH and temperature ranges, particularly if they are immobilized on some carrier, and they can degrade a wide variety of compounds. Enzymes from white rot fungi have been shown to be effective degraders of TNT, phenols, PCBs, PAHs, and dyes; enzymes such as protease, lipase, and cellulase have demonstrated the ability to reduce pathogen counts, reduce the solids content, and increase deflocculation in sludge. Currently, high production costs inhibit the widespread use of extracellular enzymes for remediation, but bench studies and field studies have shown enzymatic treatment to be feasible options for bioremediation. This paper will explore the current state of use of extracellular enzymes in enhancing the bioremediation of recalcitrant substances and wastewater, as well as the benefits and disadvantages associated with the use of such enzymes.