Screening Key Factors in Cassava-Based Bioethanol Production by Simultaneous Saccharification and Fermentation

Simultaneous saccharification and fermentation (SSF) is considered an efficient approach for bioethanol production from starchy biomass, although its performance is often affected by multiple variables acting at different stages of the process. In the present study, Plackett–Burman experimental design was used as a screening method to evaluate factors affecting ethanol production from cassava flour using Saccharomyces cerevisiae. Eleven variables related to both liquefaction and SSF stages were examined, including temperature, pH, processing time, agitation, enzyme loading, nitrogen supplementation and inoculum level, arranged in twelve experimental runs. As the experimental design was performed without replication, the effect of each variable was evaluated based on the magnitude of standardized effects and interpreted using a Pareto chart. It was observed that not all variables contributed equally to ethanol production. Among the factors tested, SSF temperature showed the most dominant effect, followed by liquefaction pH and liquefaction time within the range studied. Other variables appeared to have a relatively smaller contribution under the present conditions. These results suggest that the use of Plackett–Burman design is suitable for initial screening of variables in the SSF system, particularly when dealing with multiple factors. The outcome of this study can be used as a basis for further optimization using an experimental design with replication to obtain a more reliable estimation of the effects of significant variables.