A review of lipid-based biomasses as feedstocks for biofuels production

This review aims to provide up-to-date knowledge on existing feedstocks for biofuels production (mainly biodiesel) from lipid-based biomasses. The 1st generation of lipid-based feedstocks was edible plant oils, whilst other alternative feedstocks were discovered and reported as the 2nd generation feedstocks. The 2nd generation feedstocks that are summarized in this work include non-edible oils, waste vegetable oil, animal fats, industrial wastes and by-products, lipid derived from insects and microorganisms. The general strong points of the 2nd generation feedstocks are that they are inexpensive, of high productivity and typically do not compete ethically or economically with food crops (edible oils). However, all 2nd generation feedstocks usually have a high level of moisture and free fatty acids that cause an extremely negative effect on conventional biodiesel production process. Thus, this article provides basic information on the processing techniques that are capable of handling 2nd generation feedstocks as well.