Second generation bioethanol



Ethanol

The difference between 1st and 2nd generation bioethanol is the source of feedstock. 1st generation feedstocks are for instance corn, sugarcane and crops, whereas 2nd generation feedstocks could be agricultural waste, wood or household waste. Typically, 1st generation feedstocks are based on sucrose or starch whereas 2nd generation feedstocks are based on lignocellulose and chitin . Ethanol is produced by fermentation of glucose, which is readily achieved from the first group of feedstocks through simple hydrolysis. 2nd generation feedstocks typically consist of cellulose, hemicelluloses and lignin with the glucose bound in complex structures and more energy is required to release the glucose for fermentation. It is important to realize that the 1st generation feedstocks are also used as food for humans and animals, which is usually not the case for the 2nd generation feedstocks. The use of 1st generation bioethanol has led to a vehement debate about the ethical issues of using food for fuels, see for example reference. Contrary to 1st generation bioethanol, 2nd generation bioethanol significantly reduce greenhouse gas emissions from fuels, thus the use of 2nd generation plants are expected to increase at the expense of 1st generation bioethanol plants. Exist also a 3th generation based on algae and cyanobacteria.



Sito realizzato da Francesco Barbero nell'ambito del corso universitario "Informatica per la chimica" nell'anno accademico 2010/11 presso la Facoltà di Scienze Matematiche, Fisiche e Naturali dell'Università di Torino.