Intensification of Enzymatic Reactions in Heterogeneous Systems by Low Intensity, Uniform Sonication: New Road to “Green Chemistry

Authors: Yachmenev, Valeriy; Condon, Brian; Lambert, Allan

Submitted to: American Chemical Society Symposium Series
Publication Type: Book / Chapter
Publication Acceptance Date: 12/15/2007
Publication Date: 2/2/2007
Citation: Yachmenev, V., Condon, B.D., Lambert, A.H. 2007. Intensification of Enzymatic Reactions in Heterogeneous Systems by Low Intensity, Uniform Sonication: New Road to “Green Chemistry. In Eggleston, G. and Vercelotti, J.R., editors.American Chemical Society Symposium Series. 972. pp. 10.

Interpretive Summary: Use of enzymes in the textile, food, cosmetic, pharmaceutical and many others industries is becoming increasingly popular, mainly because of advances in biochemistry that have led to the introduction of a variety of highly specific enzymes. Enzymatic bio-processing of various substrates generates significantly less wastewater effluents which, being readily biodegradable; do not pose an environmental threat. The increasing legislative pressures by governments worldwide to sharply decrease quantity and toxicity of industrial wastewaters will ensure even greater acceptance of enzymatic bio-processing in the future. However, enzymatic bio-processing has several shortcomings that impede its acceptance by industries: expensive processing costs and relatively slow reaction rates. Our research found that the low energy, uniform sonication of cellulase and pectinase enzyme processing solutions greatly improved effectiveness of these enzymes and, as result, significantly increased the overall reaction rate of enzymatic bio-processing. On the whole, this research demonstrated that under specific conditions, carefully controlled introduction of ultrasound energy during enzymatic bio-processing has a very good potential for intensification of variety of technological processes that involve many types of industrial enzymes and matching substrates. Groups benefiting from this development include the textile, food, cosmetic, pharmaceutical and many others industries.

Technical Abstract: Use of enzymes in the textile, food, cosmetic, pharmaceutical and many others industries is becoming increasingly popular, mainly because of advances in biochemistry that have led to the introduction of a variety of highly specific enzymes. Enzymatic bio-processing of various substrates generates significantly less wastewater effluents which, being readily biodegradable; do not pose an environmental threat. The increasing legislative pressures by governments worldwide to sharply decrease quantity and toxicity of industrial wastewaters will ensure even greater acceptance of enzymatic bio-processing in the future. However, enzymatic bio-processing has several shortcomings that impede its acceptance by industries: expensive processing costs and relatively slow reaction rates. Our research found that the low energy, uniform sonication of cellulase and pectinase enzyme processing solutions greatly improved effectiveness of these enzymes and, as result, significantly increased the overall reaction rate of enzymatic bio-processing. It has been established that the following specific features of combined enzyme/ultrasound bio-processing are critically important: a) cavitation effects caused by uniform, low energy sonication enhanced the transport of enzyme macromolecules toward substrate surface, b) effect of cavitation is several hundred times greater in heterogeneous systems than in homogeneous, c) in water, maximum effects of cavitation occur at ~50 0C, which is the optimum temperature for most enzymatic reactions. In general, our research of enzymatic bio-processing of cotton textiles established that a) contrary to the common belief, low intensity, uniform sonication does not damage/inactivate sensitive structures of enzyme macromolecules, b) introduction of ultrasonic energy during enzymatic bio-processing of cotton resulted in significant improvement in enzymes efficiency. On the whole, this research demonstrated that under specific conditions, carefully controlled introduction of ultrasound energy during enzymatic bio-processing has a very good potential for intensification of variety of technological processes that involve many types of industrial enzymes and matching substrates.