Ethanol fermentation with Saccharomyces cerevisiae was carried out in a bioreactor equipped with a sintered stainless steel filter to obtain a high cell density as well as a high productivity. With a 100 g glucose/l feed, the maximum yeast concentration was 208 g/L similar to that obtained in external membrane cell recycle cultures. However, with tapioca hydrolysates, treated with activated carbon column, the yeast concentration attained was 42g/L.