Singh, AnupamaJain, Anshul2019-12-142019-12-142006-07http://krishikosh.egranth.ac.in/handle/1/5810137712Apple pomace is the main by-product of apple juice processing industries and accounts for about 25% of original fruit mass. Its disposal in the environment results in production of foul smell and affects the aquatic life and ecosystem, which compels for its proper treatment. Apple pomace contains 9.5- 22.0% carbohydrates. Fermentable sugars in apple pomace such as glucose, fructose and sucrose can be converted to ethanol using yeast. Hence an effort was made to utilize apple pomace in production of ethanol. Experiments were designed using full factorial design method. Experiments were performed in two phases. In the first phase experiments for natural fermentation of apple pomace with variables as amylase treatment (treated and untreated), pH (2.5,4.0,5.0), and fermentation time (0,36,48,60,72,84h) were carried out and based on the results obtained from natural fermentation, experiments for second phase i.e. inoculated fermentation with variables as amylase treatment (treated), pH (4.0), yeast strains (Y2, Y5 and Y12) and fermentation time (0,36,48,60,72, 84 h) were carried out. Designed experiments were conducted to find the effect of these variables on sugar utilization, pH, cell count and ethanol production. Based on the data fermentation efficiency was calculated. The data from all experiments were analyzed and the response functions were developed using multiple regression analysis and second order models were fitted for each response. In natural fermentation of apple pomace, pH 4.0 and -Amylase treatment of apple pomace resulted in higher sugar utilization (8.13%), lower residual sugar (2.34%), maximum cell growth (169 X106 cfu ml-1) and higher ethanol production (3.956 %). In inoculated fermentation, of the three strains of yeast viz. Y2, Y5 and Y12, Y5 results in maximum sugar utilization (7.756%), maximum cell growth (289 X106 cfu ml-1) and higher production of ethanol (4.074 %) at 72 h of fermentation. Out of three strains of yeast, Y5 showed maximum fermentation efficiency of 74.55%. Analysis showed that initial pH and fermenting time both affected the process of ethanol production, in natural and inoculated fermentation but effect of initial pH was more significant in comparison to fermenting time. At pH 4.0, value of Specific Growth Rate () was 0.08 h-1 for -Amylase treated natural fermentation. This correlates with maximum ethanol production of 3.95%. In case of inoculation with yeast strain, Y5 has Specific Growth Rate of 0.07 h-1 and maximum value (4.07%)of ethanol produced. The linear effect of pH and fermenting time was significant in sugar utilization, change in pH and ethanol production. The effect of interaction between pH and fermenting time was significant in change in pH and non-significant in sugar utilization and ethanol production. Hence second order model could be fitted to predict sugar utilization, ethanol production and change in pH except cell count.ennullThesis