|FRIEDL, A - Vienna University Of Technology|
|MADDOX, I - Massey University|
Submitted to: Applied Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/23/2014
Publication Date: 11/24/2014
Publication URL: http://handle.nal.usda.gov/10113/60542
Citation: Qureshi, N., Friedl, A., Maddox, I.S. 2014. Butanol production from concentrated lactose/whey permeate: Use of pervaporation membrane to recover and concentrate product. Applied Microbiology and Biotechnology. 98:9859-9867.
Interpretive Summary: Whey permeate, a by-product of dairy industry, can potentially be used as an economic feedstock for the production liquid biofuel such as butanol. Butanol is a superior fuel than ethanol and can be used as a transportation fuel in automobiles. Currently its production is uneconomic due to requirement of large amount of energy for its production using microbial strains and energy intensive product recovery from the fermentation mixture. For this reason, cutting edge science and technology development is essential which can make commercial production of butanol economically feasible. To achieve this goal we developed a process which would require less energy for both, fermentation and product recovery, use less water by a factor of 4, and reduce capital and operational costs. The developed membrane process can recover and concentrate dilute butanol solution (from 3-5 g/L) to 755 g/L. Also we combined the process of fermentation and recovery into one single operation. Use of this economic feedstock, in combination with this technology is expected to reduce the cost of butanol production substantially, thus benefitting dairy industry, dairy farmers, transportation industry, and the public.
Technical Abstract: In these studies butanol (acetone butanol ethanol, or ABE) was produced from concentrated lactose/whey permeate containing 211 gL-1 lactose. Fermentation of such a highly concentrated lactose solution was possible due to simultaneous product removal using a pervaporation membrane. In this system a productivity of 0.43 gL-1h-1 was obtained which is 307% of that achieved in a non-product removal batch reactor (0.14 gL-1h-1) where 60 gL-1 whey permeate lactose was fermented. The productivity obtained in this system is much higher than achieved with other product removal systems (perstraction 0.21 gL-1h-1, and gas stripping 0.32 gL-1h-1). This membrane was also used to concentrate butanol from approximately 2.50 gL-1 in the reactor to 755 gL-1. Using this membrane ABE selectivities and fluxes of 24.4-44.3 and 0.57-4.05 g.m-2 .h-1 were obtained, respectively. Pervaporation restricts removal of water from the reaction mixture thus requiring significantly less energy for product recovery when compared to gas stripping.