A comparison between SHF and SSSF processes from cardoon for ethanol production

• Cynara cardunculus L. was used as raw material for the production of lignocellulosic ethanol.
• Steam explosion was employed for the pretreatment of the substrate, followed by SHF and SSSF.
• Both SHF and SSSF were assessed and compared for the production of ethanol.
• The SSSF process displayed better results in terms of ethanol yield and length of the process.

The purpose of the present work is the evaluation of Cynara cardunculus L. potential in terms of ethanol production from lignocellulosic feedstock for industrial purposes. After a steam explosion (SE) pretreatment at different severity conditions, to obtain the dissolution of hemicellulose and the separation between cellulose and lignin, two different processes were tested: separate hydrolysis and fermentation (SHF) and semi-simultaneous saccharification and fermentation (SSSF). The enzymatic hydrolysis was carried out with ™Ctec2 cellulase enzyme and fermentation with Saccharomyces cerevisiae yeast.The results showed slightly better performances by SSSF process compared to SHF, especially at low severity conditions, with a maximum overall ethanol yield of 13.64 g of ethanol/100 g of raw material. For the SHF process the best overall ethanol yield achieved was 13.17 g of ethanol/100 g of raw materials. In addition, the SSSF process required at least 24 h less than the SHF to achieve the same final ethanol concentration for every severity condition tested.

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