Evaluation of flat sheet and hollow fiber supported liquid membranes for fructose pertraction from a mixture of sugars

This work investigates the use of supported liquid membranes (SLM) in the pertraction of fructose from a mixture of sugars contained in a fermentation broth. Membranes consisted in a porous polypropylene support impregnated with different kinds of carriers using 2-nitrophenyl octyl ether as solvent. Transport through flat sheet and hollow-fiber membranes was studied as a function of carrier and feed concentration. The results show that a boronic acid derivative yields the highest fructose selectivity and the hollow fiber supported liquid membrane (HFSLM) is more stable than the flat sheet system, also yielding higher fructose selectivities using lower carrier concentration. The HFSLM using a boronic acid as carrier was able to remove fructose selectively from a fermentation broth. Simulations of fructose removal from a fermentation broth were carried out using the experimental results obtained in this work. The results show that fructose removal from the fermentation broth can reduce microorganism inhibition and increase the system performance, although, further improvement in membrane stability and fluxes are still necessary.

In this work the pertraction of fructose from mixtures of fructose and glucose using flat sheet a nd h ollow f iber s upported l iquid membranes (FSSLM and HFSLM) was studied. Two kinds of carriers were tested in the flat sheet system, quaternary ammonium salts and a boronic acid hydrophobic derivative. The latter showed the best fructose extraction properties. The flat sheet system produced fructose/glucose selectivities up to 14, while in the hollow fiber system fructose fluxes 20 times higher than glucose w ere o btained, u sing l ow c arrier concentrations. Preliminary tests show that a HFSLM using boronic acid as carrier was able to extract fructose from a fermentation broth. Simulation results showed that the HFSLM coupled to a bioreactor i s c apable o f d ecreasing microorganism i nhibition b y f ructose accumulation in the medium, although future work needs to improve membrane stability and increase the fructose flux.