Solid state fermentation of apple pomace for concomitant production of ethanol and animal feed

Effect of some factors on solid state fermentation (SSF) of apple pomace using three different yeasts and natural fermentation were studied. Natural fermentation of apple pomace was inferior to the yeast inoculated fermentation for ethanol and crude and soluble proteins production. The production of ethanol in natural fermentation was almost half than that of Saccharomyces cerevisae fermented pomace. The optimum time for ethanol production in SSF was 96h. Saccharomyces cerevisiae gave highest ethanol yields. Ethanol production by Candida and Torula was comparable. Combination of ammonium sulphate and zinc sulphate proved detrimental to ethanol and crude proteins and soluble proteins production both by natural microfloral and inoculated yeasts fermentation. The natural microflora also responded better to ammonium sulphate than the addition of ammonium sulphate in combination with zinc sulphate.