| Author | Audu, Idi Guga |
| Call Number | AIT Diss. no.FB-12-06 |
| Subject(s) | Typha
|
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering i n Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. FB-12-06 |
| Abstract | The possibility of using Typha capensis (TC), a fast growing invasive grass of the wetlands , as a ren ewable feedstock for bioethanol and high profile biomaterial production was investigated . Composition analysis was carried out and pretreatments conducted using three methods: ionic liquid (IL), organosolv and a two stage dilute sulfuric acid. Cellulase fr om Trichoderma (C9748) mixed with Cellobiase from Aspergillus niger (C6105) were first characterized and optimal combination determined and then used to hydrolyze pretreated substrates. Composition analysis of the grass shows values of 36.25%, 16.35%, 19 .05% and 20.76% for cellulose, hemicelluloses, lignin and extractives respectively. The optimum condition for each pretreatment method was determined based on improved enzymatic digestibility. The IL method gave the maximum reducing sugar yield of 93.93 g /100 g substrates, followed by sulfuric acid catalyzed ethanol organosolv pretreatment with a value of 78.12 g/100 g substrates and then the two stage dilute sulfuric acid pretreatment with value of 67.74 g/100 g substrates taking into account the combined benefits from the two stages. As the costs of IL’s are high, alkali and acid pre - hydrolysis and reusing were used to improve the economics. Alkali pre - hydrolysis provided better synergy to IL and reduced pretreatment time from 6 hrs to 15 minutes and tot al solid was increased from 5 to 10% without significant reduction in the sugar yields. During solvent reusing , about 10% of initial lignin at each cycle was being accumulated into the liquid stream containing the IL with minimal traces of carbohydrates. T reatment of the reused IL at 10 th and 15 th cycles enabled recovery of about 93% of the ionic liquid soluble lignin released into the liquid stream and improved the effectiveness of pretreatment. Treatment of IL after every 5 cycles is recommended and could enable reuse of IL for up to 15 cycles without significant reduction in sugar yields. Beside the benefits of obtaining fermentable sugar yields from the organsolv option, 67% of lignin in the raw TC was also extracted as ethanol organosolv lignin (EOL). 13 Carbon NMR analysis of the EOL shows no signal for sugars and other impurities indicating high purity lignin suitable for some specialized industrial applications. In both ethanol organsolv and dilute acid pretreatment, it was observed that TC polysaccha rides were particularly susceptible to hydrolysis, which was associated with the formation of a large amount of pseudo - lignin due to the degradation of sugars. Pseudo - lignin had a negative impact on enzymatic hydrolysis. Typha capensis has great prospect s as a non - food lignocellulosic for bioethanol production as well as a source for other high value biomaterials like lignin. Thus, there is considerable potential for the beneficial utilization of this fast growing invasive that otherwise remains an enviro nmental threat in many developing countries. |
| Year | 2012 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. FB-12-06 |
| Type | Dissertation |
| 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;Salam, Abdul;Anal, Anil Kumar |
| Scholarship Donor(s) | International Fellowships Program - Ford Foundation , USA;AIT Fellowship |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2012 |