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

摘要

Enzymatic bio-processing of various substrates generates significantly less wastewater effluents that are readily biodegradable, and do not pose an environmental threat. However, two major shortcomings that impede acceptance by industry are expensive processing costs and slow reaction rates. Enzymatic bio-processing of cotton textiles with cellulase and pectinase enzyme processing solutions, under low energy, uniform sonication greatly improved the efficiency of the enzymes and significantly increased the overall reaction rates. Specific critical features of combined enzyme/ultrasound bio-processing are: a) cavitation effects that enhance the transport of enzyme macromolecules toward the substrate surface, b) the several hundred fold greater effect of cavitation in heterogeneous than homogeneous systems, and c) the maximum effects of cavitation at ～50℃ that are optimum temperature for most enzymatic reactions. Contrary to common belief, low intensity, uniform sonication does not damage or inactivate sensitive structures of enzyme protein macromolecules. Overall, under specific conditions, carefully controlled introduction of ultrasound energy during enzymatic bio-processing has an excellent potential for the intensification of a variety of technological processes that involve many types of industrial enzymes and substrates.