Solid state fermentation of Apple pomace as affected by combinations of enzymatic treatment and yeast strains

Apple pomace (AP) is main by-product of apple processing industries which accounts for 25% of original fruit mass and contains considerable amount of sugars. Cellulase and amylase enzymes were used to raise the initial sugar content of the AP sample. Fermentation of AP was conducted on laboratory scale in 250 ml flask at 30°C at different pH levels of 4, 4.5 and 5.0 using the Y₅₁ strain, Saccharomyces cerevisiae 3206 and their combination. Ethanol yield of 5.23% was obtained in the case where strain Y₅₁ was used as inoculum, initial pH of the sample was 4.5 and the fermentation period of the sample was 72 hours. Fermentation efficiency in this case was found to be 82%. (Design Expert 7.1.6) was used to design the experiments and to analyze the obtained data.