Optimization of Fermentation Parameters for Production of Ethanol from Industrial Potato Waste by Simultaneous Saccharification and Co-Fermentation in Biofilm Reactors

Bioethanol is a renewable energy source as an alternative to fossil fuels. Bioethanol is produced from starchy biomass in the U.S. such as corn.  However, a cheaper non-food value source is needed. On the other hand, to reduce the cost of ethanol and improve the effectiveness of the process, cell immobilization can be employed in ethanol production. Plastic composite supports (PCS) are solid supports used to stimulate biofilm formation in bioreactor (a.k.a. biofilm reactor) during microbial production of value-added products. Therefore, in this study, industrial wastes of a local potato company is utilized for simultaneous saccharification and ethanol fermentation in biofilm reactors by Aspergillus niger and Sacchaorymes cerevisiae. To achieve the high biomass yield in the reactor, biofilm immobilization technique is employed with Plastic Composite Support (PCS) material. The PCS, which includes polypropylene, soybean hull, soybean flour, yeast extract, and salts, is selected based on biofilm formation on PCS. Growth parameters are optimized using a three-factor Box–Behnken design of response surface method. Factors that are selected for optimization are pH, temperature, and aeration.