The Performance of Start-Up Process in Continuous Ethanol Production Using Integrated Aerobic–Anaerobic Baffled Reactor (IAABR)

Ethanol is a chemical having an important role in human life. It is a solvent, a disinfectant or can be derived into related products or used as a biofuel for gasoline engine. The aim of this research was to study a startup process of continuous ethanol production from molasses using Saccharomyces cerevisiae in an integrated aerobic–anaerobic baffled reactor (IAABR) with 10 l working volume. The batch and continuous phases of the start-up process were investigated. In batch phase, inoculum 10% v/v was added at the first compartment and incubated aerobically for 24 hours. Subsequently, the suspension cell was distributed into four compartments and continuous phase was initiated. The molasses medium was fed into the reactor at flow rate of 0.5 l/h during the continuous phase. All of the process, medium temperature was maintained at about 30 °C. The ethanol concentration obtained in the batch phase was 4.45% or equivalent to yield of 0.41 g ethanol/g sugar, while the concentration achieved 6.75–8.5% after 62 hours continuous fermentation or total yield for continuous phase 0.40 g ethanol/g sugar. During the continuous phase, the yields in compartment A, B, C, and D are 0.39, 0.24, 0.22, and 0.19 g ethanol/g sugar, respectively.