Bioethanol Optimization in Hydrolysis and Fermentation Process with Surface Response Method

The starch content in the liquid waste of tapioca flour can be processed into glucose by chemical hydrolysis process with solid NaOH, and filtrate glucose obtained can be processed into technical bioethanol with fermentation process using turbo yeast. This study aims to produce maximum technical glucose and bioethanol with optimization in hydrolysis and fermentation processes using Minitab software with Surface Response. Before the hydrolysis process, tapioca flour's liquid waste underwent a pretreatment and filtration process to remove impurities. The hydrolysis process chemically uses solid NaOH with liquid waste tapioca flour as 5 liters and hydrolysis temperature ± 40°C. Variables in the form of solid NaOH 1 to 5 mg, and stirring time 15 to 60 minutes using digital magnetic stirrer type MS-20D. The fermentation process uses a volume of glucose filtrate 500 ml, fermentation temperature ± 30°C, and fermentation pH ±4.5, variable levels of turbo yeast 7 to 15 (% w/v) and fermentation time of 3 and 7 (days). The maximum levels obtained for glucose are 18%, and technical bioethanol is 21.9 %v/v, with the Response Surface method showing similarities to the second-order polynomial model.