Second Generation Bioethanol from Lignocellulosic Biomass Using Worm Tea as Pretreatment Siti Norfariha M.N. 1 , Siti Aisyah I. 2 , Nur Farehah Z.A 3 , Renuka R. 4 and Norli I. 1 1,2,3,4,5 School of Industrial Technology, Environmental Technology Division, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia Abstract. Production of ethanol from mixed fruit waste (biomass) to represent lignocellulosic biomass was investigated. Worm tea was used as an alternative for the pretreatment of fruit waste. A 2 k fractional factorial experimental design was used to analyze the five factors use in this study (pH, temperature, biomass loading, worm tea ratio and heating time). Results from the analysis revealed loading and ratio had the strongest effect on the bioethanol yield with the highest reading of 0.501mg/l. Keywords: mixed fruit waste, lignocellulosic biomass, bioethanol, pretreatment, worm tea, factorial design 1. Introduction Bioethanol is considered as a sustainable alternative to gasoline to mitigate the global energy problem due to depletion of fossil fuel and also to reduce greenhouse gas emissions. The food and fuel conflict due to the production of first generation bioethanol from sugar and starchy food materials is an important issue from the food security point of view (Guragain et al., 2010). In order to avoid the competition with food, use of abundantly available and non-edible parts of plants including agricultural wastes, fast growing aquatic plants as feedstock is being attempted to produce second generation bioethanol (Hu et al., 2008). Lignocellulose is considered an attractive feedstock for the production of fuel ethanol because of its availability in large quantities at low cost (Cardona and Sánchez, 2007; Cheng et al., 2009). Lignocellulosic materials are mainly comprised of cellulose, which is a glucose polymer, hemicelluloses, a mixture of polysaccharides composed mainly by glucose, manose, xylose, arabinose, and lignin (Saxena et al., 2009). Bioethanol production processes involve three important steps-mechanical processing and pretreatment of the material; hydrolysis of the pretreated material; and finally fermentation of the hydrolyzed material by a suitable microorganism to produce ethanol (Mishra et al., 2011). A pretreatment process is required in order to separate the lignin and hemicelluloses from the cellulose, reduce crystallinity and increase the porosity, thus improving cellulose hydrolysis (Kuo and Lee, 2009). Some pretreatment methods including acid pretreatment, wet oxidation and lime pretreatment seem to be economically more feasible than others such as biological pretreatment. However due to environmental concern and production of furfurals which inhibit the yeast fermentation during these pretreatment processes are known to be a major hurdle that needs to be overcome for commercial production of bioethanol (Hu et al., 2009; Hendriks et al., 2009; Mosier et al., 2005). Therefore, the development of efficient, cost effective and environmentally friendly pretreatment method is important (Hendriks et al., 2009). In this experiment worm tea is use throughout the bioethanol production process which includes pretreatment, enzymatic hydrolysis and fermentation. Vermicomposting produces a leachate as micro- organisms release water during the decomposition of the organic material. Leachate derived from  Corresponding author. Tel.: + 006-04-6532824 fax: +006-04-6573678. E-mail address: norlii@usm.my 2013 4th International Conference on Biology, Environment and Chemistry IPCBEE vol.58 (2013) © (2013) IACSIT Press, Singapore DOI: 10.7763/IPCBEE. 2013. V58. 1 1