Acetic acid is a well-known microorganism inhibitor which is co-generated during lignocellulosic biomass pretreatment. Cell immobilization techniques, on the other hand, could create a microenvironment for the biocatalyst that protect cells from the inhibition effect. Taking this into account, this work aimed to analyze whether the presence of an alginate gel matrix can protect immobilized recombinant S. cerevisiae from acetic acid toxicity. For this purpose, fermentation runs were carried out in YPX 40 g/L with different acetic acid concentrations and using free and immobilized cells of T18 yeast. The support matrix did protect the immobilized cells and thus favored yeast performance, improving fermentation time and allowing the immobilized yeast to ferment xylose in the presence of higher acetic acid concentrations than the free cells.