Sonic Assisted Membrane Processing--Montec Associates, Inc., P.O. Box 4182, Butte, MT 59702-4182; 406-494-5555
Mr. Steven F. McGrath, Principal Investigator
Mr. Lawrence C. Farrar, Business Official
DOE Grant No. DE-FG03-99ER82836
Amount: $750,000

The economical conversion of many commodity production lines to environmentally friendly biotechnology processes is limited by the downstream operations of separating product from biocatalyst, rather than by the complex technology associated with the directed evolution of enzymes. Although membrane filtration with micro-sized pores has become the separation technology of choice for the biotechnology industry, the protein solutions have a proclivity to foul the membranes during filtration. None of the techniques commonly used to improve ultrafilter performance, such as high cross flow velocity, can be used with proteins. New technology is needed to improve the performance of membrane separations to allow the existing capabilities of biotechnology to evolve into economical processes. This project will address the membrane-fouling problem by coupling filtration technology with a mechanically driven low frequency acoustic resonator. The acoustic pulses from the resonator impinging on the membrane create a micro turbulence near the face of the membrane that assists in keeping the flux of permeate from falling due to the buildup of a resistive gel layer. Phase I demonstrated the enhancement of permeate flux through a 10,000 molecular weight cut off (MWCO) membrane from solutions with 1 to 5 percent protein (as pepsin). Enhancements were most pronounced for conditions with no cross-flow velocity. These are precisely the conditions in which a free enzyme bioreactor would need to function because of the detrimental effect of cross flow shear on proteins. The Phase II project will optimize the design of a membrane bioreactor for use in specific industrial processes. It will further demonstrate that enzymes proposed for use in these processes are not degraded in the sonic environment. A pilot scale modulator bioreactor will be fabricated and mobilized for continuous testing of the new enzymatic based production.

Commercial Applications and Other Benefits as described by the awardee: In addition to myriad applications in biotechnology, which include traditional fermentation processes, this acoustically enhanced membrane filtration technology should have broad application in industrial separations where membrane usage is predominantly limited by the fouling problem. Food processing, chemical manufacturing, municipal water treatment, and waste treatment are but a few of the markets that would readily accept a simple new technology that improves membrane performance by a factor of 5 to 10.