DIRECT BIOCONVERSION OF OIL PALM EMPTY FRUIT BUNCHES FOR BIOETHANOL PRODUCTION BY SOLID STATE BICONVERSION

Bioethanol production was conducted by utilizing empty fruit bunches (EFB) with the treatment of mixed culture of fungi and yeast in solid state bioconversion process. The compatibility of several fungal and yeast was tested to develop direct solid state bioconversion using the potential mixed culture. The mixed culture of a fungus (Trwhoderma harzianum) and a yeast (Saccharomyces cerevisiae) showed a good potential as they produced higher ethanol (14%) among the other mixed culture combination in liquid-broth fermentation. The optimization of process condition was performed with varied level of moisture content, pH, inoculum size, concentration of co- substrate and mineral solution by using the central composite design (CCD). The optimum process conditions giving maximum ethanol production (14 1%) were- moisture of 60%, pH of 7, inoculum size of 4%, co-substrate concentration of 2% and minerals concentration of 2%. The results indicated that pH, co-substrate and minerals concentration were highly significant (p 0.01) followed by moisture content (p 0 05) and inoculum stze (p 0.05). The coefficient of determination (R2) was 99.6% which satisfied the adjustment of experimental data in the model. A validation experiment was carried out to evaluate the process conditions obtained from the model.