PEMANFAATAN KULIT CEMPEDAK SEBAGAI BAHAN BAKU PEMBUATAN BIOETANOL DENGAN PROSES FERMENTASI MENGGUNAKAN SACCHAROMYCES CEREVISEAE

Along with prevention efforts of fossil fuel crisis in the future and the implementation of government programs on energy policy, it is necessary to research on renewable energy such as bioethanol. The raw material for bioethanol production usually contain high enough carbohydrates and carbohydrate of jackfruit is 28.6 g/100 g jackfruit. This study aims to determine the effect of the process of acid hydrolysis treatment against the degradation of lignin in the skin fibers of jackfruit, determine the optimum weight of jackfruit skin to the process of acid hydrolysis treatment, know the optimum pH and right nutrient to produce the highest ethanol content. Jackfruit skin was cut, roasted and refined to powder and then analyzed the structure of the morphology using SEM and crystallity using XRD methods. The powder is added with solution of H2SO4 (2% v/v) and 90 mL of distilled water and hydrolyzed at 100°C for 1 hour with a variety of heavy of jackfruit skin (%w/v) as follows: 2.5%; 5%; 7.5% and 10%. Hydrolyzate with the highest glucose levels do variations in pH, which is 4; 4,5 and 5 sterilized using an autoclave for 15 minutes. The hydrolyzate is added starter that has been activated and Saccharomyces cerevisiae then fermented in orbital shaker at 120 rpm for 4 days. The fermentation process is repeated by adjusting pH 4.5 at hydrolyzate and add a variety of nutrients, namely 0.1 g urea; 0.1 g NPK; and 0.05 g urea+0.05 g NPK. The content of bioethanol tested with GC method. Based on XRD, the characteristic of peak of cellulose of jackfruit fiber skin is increased. Crystallinity Index before hydrolysis 20.39% and 24.59% after hydrolysis. From the analysis by the Luff-Schoorl method obtained the highest total sugar content with weight of jackfruit skin of 7.5% (w/ v) is 15.25% (v/v). While the results of the analysis by GC method to variations in pH and nutrient is obtained a highest content of bioethanol is 0.810% (v/v) at pH 4.5 and 0.731% (v/v) with the addition of 0.05 g urea+ 0.05 g NPK.