Membrane bioreactors improve the production of lignocellulosic-ethanol

Membrane bioreactors (MBRs) are widely used in wastewater treatment plants because they intensify the biotreatment process, reduce the number of processing stages, retain the biocatalyst and help remove the product from the suspended solids. In order to take advantage of these benefits, as well as to enable continuous production, membrane modules have been developed and tested for lignocellulosic-ethanol production by researchers at the Dept. of Resource Recovery, University of Borås (Sweden; www.hb.se), with cooperation and support from the Flemish Institute for Technological Research (VITO NV; Mol, Belgium; www.vito.be). “Pressure-driven flat-sheet microfiltration immersed membrane bioreactors (iMBRs) were integrated into different processing stages of lignocellulosic ethanol production,” according to Amir Mahboubi Soufiani, who defended his doctoral thesis last November. “The continuous fermentation iMBR set-up used for bioethanol production from wheat straw hydrolysate could operate at unconventionally high concentrations of suspended solids up to 20% w/v without significant deterioration of the filtration properties. This is ten times higher than the 0.8–2% solids loading operation of conventional iMBRs,” he says.…