Thesis
Enzyme hydrolysis of cassava peels for ethanol production
- Creator
- Rights statement
- Awarding institution
- University of Strathclyde
- Date of award
- 2013
- Thesis identifier
- T13534
- Qualification Level
- Qualification Name
- Department, School or Faculty
- Abstract
- The enzyme hydrolysis of cassava peels for ethanol production provides an interesting research opportunity to convert starch rich lignocellulose waste into renewable fuel production. The research involved the pretreatment of cassava peels with steam explosion and hot water pretreatment processes as well as combining both amylolytic and cellulolytic enzymes to produce simple sugars. This research compared different enzyme treatment strategies; a separate hydrolysis that involved the treatment of the peels with either cellulolytic enzymes or amylolytic enzymes, a consecutive hydrolysis process which is a follow up of the separate hydrolysis in which sugars were washed from the initial enzyme treatment (amylase or cellulase treatment) and the cassava peels resuspended for further enzyme treatment was also investigated. Another treatment strategy employed in this study was the simultaneous hydrolysis by amylases and cellulases of the cassava peels. The hydrolysis rate and yield were compared for each process. Minor changes that incorporated steam explosion pretreatment and hot water pretreatment were also studied. A separate hydrolysis of milled cassava peels treated by amylolytic and cellulolytic enzymes yielded a maximum reducing sugar of 0.41g (as glucose) per gram of peels and 0.31g per gram of peels respectively. Also steam exploded cassava peels treated by amylolytic and cellulolytic enzymes yielded maximum reducing sugars of 0.24g per gram of peels and 0.37g per gram of peels respectively. Results also showed that a consecutive treatment that incorporates an initial hydrolysis by cellulolytic enzymes followed by a subsequent treatment by amylolytic treatment yielded reducing sugars of 0.64g per gram of milled cassava peels. A reverse treatment where the cellulolytic enzymes were used to first treat the peels before a second treatment by amylolytic enzymes yielded 0.61g reducing sugar per gram of milled cassava peels. A simultaneous hydrolysis by both cellulolytic and amylolytic enzymes produced a maximum reducing sugar of 0.58g per gram of milled cassava peels. A modification that incorporates hot water pretreatment, simultaneous and consecutive treatment was carried out. The milled cassava peels treated with hot water at 1000C and amylase enzymes for 2 hours were further subjected to a simultaneous saccharification by cellulases and glucoamylase enzymes yielded a reducing sugar of 0.62g per gram of peels. Fermentation experiments were also carried out with Kluyveromyces marxianus at 400C and results showed a maximum ethanol yield of 0.12g ethanol per g of cassava peels for a separate hydrolysis and fermentation process and 0.18g ethanol per g of cassava peels for the simultaneous saccharification and fermentation process. It was concluded that cassava peels presents a very good source of sugars for bioethanol production.
- Resource Type
- DOI
- Date Created
- 2013
- Former identifier
- 996800
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