Integration of 1st and 2nd generation bioethanol fuel production: Opportunities and limitations

Bioethanol currently is the most widely used transport biofuel in the world. At present, it is mainly produced from starch-rich grains and sugar cane (the first generation bioethanol fuel). Starch and sugars from existing food materials limit its feedstock supply, and its sustainable production is facing great challenges. Production of bioethanol fuel from the lignocellulosical materials (the second generation bioethanol fuel) has aroused great interest in recent decades because the lignocellulosical materials, such as agricultural and forestry wastes and organic industrial wastes, are abundant, widely available, and inexpensive. However, its large-scale industrial production is still not economically feasible because of high pretreatment and enzyme costs, as well as low ethanol final concentration and yield, based on current technology. Some recent studies indicate that the integration of the first and second generation of bioethanol fuel production can increase the final ethanol concentration and yield, reduce the enzyme and water usage, and effectively improve its process economy. This editorial will give a brief discussion on the integration of the first and second generation of bioethanol fuel production.