| Author | Paphawee Nantarajit |
| Call Number | AIT Thesis no.FB-10-11 |
| Subject(s) | Eucalyptus camaldulensis
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. no.FB-10-11 |
| Abstract | Pulp and paper is one of the important industries in Thailand. The wood tops of Eucalyptus camaldulensis are always leftover from the paper industries due to their smaller diameter and lower amount of cellulose content. Hence, the wood tops of Eucalyptus can be the potential raw material for the production of cellulosic ethanol. The purpose of this study was to determine the possibility of using alkali and laccase-mediator pretreatment to improve the enzymatic sachharification and microbial fermentation yield. The initial chemical compositions of the raw wood tops of Eucalyptus camaldulensis were 57.29% of cellulose, 15.37% of hemicellulose, and 27.34% of lignin content of dried biomass. The raw woody biomass underwent two different physical pretreatments; grinding and milling to obtained wood fiber and wood powder, respectively. The physical pretreated wood fiber and wood powder were further underwent sodium hydroxide pretreatment. All chemical compositions analysis followed TAPPI protocols, and indicated that 8% (v/v) sodium hydroxide, 121° C for 60 minutes pretreatment of both wood fiber and wood powder, can achieve the most lignin removal. The sodium hydroxide pretreated wood fiber and wood powder were further tested for enzymatic hydrolysis using a mixture of cellulase and hemicellulase, and total reducing sugar yields of each conditions were determined as the saccharification yield. It was found that the maximum sugar yields obtained from 4% (v/v) sodium hydroxide pretreated wood fiber and wood powder at 3% substrate concentration were 540.18 mg/g-substrate and 650.49 mg/g-substrate, respectively while an increase of substrate loading led to lower sugar yields. When increasing enzyme loading, it was found that the sugar yields of sodium hydroxide pretreated wood fiber and wood powder were increased because the level of enzyme loading still less than the critical level. In addition, using laccase-mediator delignification by using ABTS and Vanillin as mediator substance, it was evident that its toxicity from oxidized compounds generated during delignification inhibited the activity of cellulase and hemicellulase so the sugar yields were very low. The enzymatic hydrolysates of 4% (v/v) sodium hydroxide pretreated wood fiber and wood powder and used for microbial fermentation into ethanol by Saccharomyces cerevisiae. As a result, the maximum ethanol yield of pretreated wood fiber hydrolysate was achieved after 8 hours of fermentation with yield 0.45 g/g while the maximum of ethanol yield from pretreated wood powder hydrolysate was obtained at 12 hours of fermentation with 0.43 g/g ethanol yield. Overall, it is clear that the Eucalyptus top cuts have good potential to save as starting raw material for the production of second generation bio-ethanol. |
| Year | 2010 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. no.FB-10-11 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Rakshit, Sudip Kumar; |
| Examination Committee(s) | Athapol Noomhorm;Anal, Anil Kumar; |
| Scholarship Donor(s) | RTG Fellowship; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2010 |