Comparison of strategies for the simultaneous saccharification and fermentation of cashew apple bagasse using a thermotolerant Kluyveromyces marxianus to enhance cellulosic ethanol production

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 307; pp. 939 - 947
• Main Authors: de Barros, Emanuel Meneses, Carvalho, Victor Martins, Rodrigues, Tigressa Helena S., Rocha, Maria Valderez Ponte, Gonçalves, Luciana Rocha B.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-01-2017
• Subjects: Cashew apple bagasse; Fed-batch SSF; Second generation ethanol; SSF; Fed-batch SSF; Cashew apple bagasse; Second generation ethanol; SSF
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2016.09.006

•SSF strategies for ethanol production from CAB was investiagted.•A pre-saccharification step was conducted prior to SSF.•Fed-batch SSF process enabled the increase in final ethanol concentration from CAB.
Simultaneous saccharification and fermentation (SSF) is a promising process for the bioconversion of lignocellulosic biomass. Furthermore, an efficient approach to reduce the capital costs for the production of bio-based products is the use of high glucan loading. Therefore, in this study, a comparison of SSF strategies were investigated aiming to enhance ethanol production from acidic-alkaline pretreated cashew apple bagasse (CAB-OH) by Kluyveromyces marxianus ATCC36907 at high glucan loading. An ethanol concentration of 58g/L was achieved with 15% CAB-OH using batch SSF, resulting in an 81.2% overall ethanol yield. Prehydrolysis of 12h, prior to SSF, did not significantly increase the overall ethanol yield. Fed-batch SSF, using high loadings of solids, was also investigated. Ethanol concentrations of up to 67g/L could be produced from CAB-OH (20% w/v) by adding fresh substrate every 4h during the first 48h of SSF (10% initial and 2.5% of feeding), achieving an overall ethanol yield of 81%. In the fed-batch mode, the amount of enzyme was lower than used in batch and this process allowed higher ethanol concentrations and similar yield. No major differences in fed-batch performance, considering ethanol concentration and yield, were observed for the different feeding amounts, around 68g/L and 80.7%, respectively.