T apioca solid waste is a by product of processing waste in the form of tapioca flour and a lot of carbohydrates that can be developed in a way beneficial to process waste through the process of acid hydrolysis and fermentation. This study aims to know the value of C/N as a way to know the rate of decomposition of organic materials and know the level of ethanol produced from the hydrolysis and fermentation processes on solid waste of tapioca. Hydrolysis carried out by using 1.5% 1M H2SO4. Fermentation of microorganisms is done by variation 10% and 20% in mixed culture with Bacillus licheniformis, Aspergillus niger and Saccharomyces cerevisiae in solid waste tapioca 50 gr, 100 gr, 150 gr and 200 gr. The highest ethanol content in microorganisms variation occurs in 10% 50 g substrate to 120 hours is 4.40% with the number of microorganisms 2.291017 colony/ml, pH = 4.60, the value of C/N = 36.43. In a variation of microorganisms 20%, the highest ethanol content occurs in the substrate 50 grams to 120 hours is 3.26%, the number of microorganisms 1.82x1017 colony/ml, pH = 3.70, the value of C/N = 49.33. Value of the kinetics of solid waste 50 gr tapioca, μ = 0.003206 – 0.009712 1/hour, μm = 0.00006120 /hour, Ks = 1036.78 mg/1, Y = 23.79, q = 0.000135 – 0.000408 1/hour, YT = 23.79 /hour, Yobs = 1.8147 – 5.4977 /hour and Kd = 0.0323 – 0.0388 /hour. Value of the kinetics of mixed culture at 20% solids 50 g tapioca, μ = 0.001818 – 0.008016 1/hour, μm=0.00004288/hour, Ks= 965.94 mg/1, Y = 7.27, q = 0.000250 – 0.001103 1/hour, YT = 7.27 /hour, Yobs = 0.0961 – 0.4235 /hour and Kd = 0.1296 – 0.1358 /hour.