ULTRAFILTRATION OF XANTHAN GUM FERMENTATION BROTH - PROCESS AND ECONOMIC-ANALYSES

Energy consumption and operating costs for xanthan recovery from dilut e fermentation broth using ultrafiltration and alcohol precipitation w ere studied. Ultrafiltration can be used to concentrate xanthan fermen tation broth from 2.5 to 15% (w/v) xanthan. The effects of xanthan con centration, transmembrane pressure difference and shear and pumping ra tes on the performance of ultrafiltration were studied. Engineering de sign equations for modelling filtrate flux and pressure drop during ul trafiltration of xanthan broth were also developed and used in the pro cess analysis. The optimal conditions for maximum filtrate flux, minim um membrane costs and minimum energy costs were determined. It was fou nd that up to 80% of the energy used in recovering xanthan gum from fe rmentation broth can be saved by using ultrafiltration to concentrate the broth before alcohol precipitation. (C) 1997 Elsevier Science Limi ted.