Comparison of process configurations for ethanol production from two-step pretreated sugarcane bagasse

The use of pretreated sugarcane bagasse for ethanol production was investigated by comparing three process configurations, separate hydrolysis and fermentation (SHF), simultaneous saccharification and fermentation (SSF) and presacchararification followed by simultaneous saccharification and fermentation (PSSF). Design of experiments was applied to the different configurations. Glucose concentration and glucose yield were selected as response parameters for the saccharification step, while ethanol concentration and amount of bagasse per liter of ethanol were taken as comparison parameters among the three process configurations. Best values for ethanol yield of 81.6, 59.4 and 68.4% of theoretical yield based on glucose content in raw material were achieved for SHF, SSF and PSSF, respectively. From one ton of sugarcane bagasse it is possible to obtain, under these experimental conditions, 192, 172 and 198 L of ethanol, respectively. PSSF is the best process configuration based on ethanol yield and on volume of ethanol that can be produced from one tone of sugarcane bagasse. Further studies will be focused on increasing working scale.

► Cellulase load and solid concentration were significant for glucose concentration and glucose yield in enzymatic hydrolysis study.
► The ethanol yield was upper 79% compared with theoretical yield for both pretreatment methods in HFS configuration.
► It is possible to obtain for each ton of bagasse, 172.5 L of ethanol with SSF configuration.
► It is possible to obtain for each ton of bagasse, 193.6 L of ethanol with PSSF configuration.
► PSSF can be considered the best alternative strategy.