SHORT-TERM LIME PRETREATMENT AND ENZYMATIC CONVERSION OF SAWDUST INTO ETHANOL By Augustine Omoniyi AYENI (CUGP050132) A Thesis Submitted in the Department of Chemical Engineering to the School of Post-graduate Studies As part of the requirements for the award of the degree of Doctor of Philosophy (Ph.D.) in Chemical Engineering of Covenant University, Ota, Ogun State, Nigeria June, 2013