The developed methodology is expected to facililtate the transition from petroleum to renewable carbohydrate-based chemical production. In this project different synthetic membranes will be developed by solvent casting of polyamide 4,6 and polysulfone grafeted with polyvinylllidone, ethylene vinyl acetate or polyethylene glycol to modulate the permeability. Yeast and filamentuos fungi will be encapsulated in these membranes. The performance of the membrane capsules will be evaluated in terms of permeability to water, gas and metabolites, impermeability to the microorganisms, biocompatibility, mechanical strength and chemical robustness. The performance of the encapsulated microorganisms will be compared with free cells with respect to productivities, tolerance against toxic materials in the culture media, bacterial contamination and osmotic stress. The pysuological state of the encapsulated cells will be thoroughly studies using genome-wide technologies and mathematical modelling.