| A membrane bioreactor (MBR) is a system integrating a membrane process into a bioreactor. A MBR has some features superior to a general bioreactor, and been attracting more and more researchers and even the public.A membrane is a dominant factor for design of membrane bioreactor. The performance of a MBR depends upon behaviors of the used membrane to much great extent. Silicone rubber (PDMS) is a polymer with preferential absorption for volatile organic compounds, such as alcohols, ester, phenol, aromatic, hydrocarbon, ketone, halogenation, pyridine,from their water solutions. It is also one of the best air-permeable membrane materials. In this study, we built a MBR with a composite silicon rubber (PDMS) membrane prepared in our laboratory, which had a working volume of 5 liters, and conducted a series of fermenting experiments for apple juice with the MBR. The experimental design was based on an idea of suspended growth and close-circulating renewal of the yeast cell and recovery in situ of the product.At first, we have selected a microorganism from three strains of yeasts, through acclimatization cultures. The selected microbe showed better behavior for apple juice ferment. With the built silicone rubber(PDMS)membrane bioreactor, ferment of apple juice and pervaporation of the fermenting broth was coupled, and light components produced by the microbes, mainly ethanol, was separated and recovered. During ferment, the cellular density in the broth can reach 108/ml in 24~36 hours at 25℃, and after the metabolite- ethanol was removed from the membrane bioreactor...
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