Using Short Ozonation Exposure Pretreatment as a Feasible Process for Ethanol Bio-Fuel Production from Plant Wastes

Increasing demand for developing a new sustainable and green source of fuels for transportation replacing the fossil fuels used today, led to blended gasoline with bio-ethanol as an optimal alternative solution. Plant (Lignocellulosic) wastes, although require pretreatment processes, appears to be the most promising sustainable feedstock resource for bio-ethanol production rather than being buried at dumping sites or burned. The source of biomass used in this study was shredded trimmings. The composition of this lignocellulosic wastes analyzed by Thermogravimetric Analysis (TGA) was 49% cellulose and 25% lignin. The presence of lignin hampers cellulose conversion to glucose and requires expensive and polluting pretreatment processes. Although ozonation is a nonpolluting, effective and competitive pretreatment method, it is not commercially being used because of high energy requirements in ozone production. HPIC sugars analysis showed that reducing ozonation time to 15 minutes removed 18% of lignin in 40 gr/L lignocellulosic wastes, while producing high enzymatic effect of fivefold amount of glucose compared to untreated sample (7.5% vs 1.5% conversion, respectively). Moreover, one and half fold of the recommended enzymes dose (by the manufacturer) more than tripled the glucose amount (24% conversion) which demonstrates the effectiveness of the pretreatment method by itself. These results indicate that reducing the duration of ozonation may alter the use of this process more realistic and thereby more feasible.