Possible ways of bio-refining and utilizing the residual lignocelluloses of corn growing and processing

Abstract

The events of the past five years showed that the most promising alternative liquid fuel is the bioethanol, which could replace fossil fuels, thus impeding the further acceleration of the global warming. The bioethanol production of the world showed a significant growth, which was basically caused by the increase of corn starch processing and fermentation. However, the growing and the processing of corn results in lignocellulosic by-products like corn stover, corncob, corn fiber, and press cake. The weight of the starch is only \sim 25% of the whole corn plant. The further increase of corn growing and processing will increase the production of the lignocellulosic by-products as well. The idea of ``bio-refining´´ means the fractionation of the biomass with chemical and biotechnological methods, and producing value added products from each fraction. The goal of most researches in the field of lignocellulose utilization is the production of ethanol. Most authors conclude that it is not economical because of the high ratio of the yet unutilizable fractions, like hemicellulose and lignin. But if these fractions could be sharply separated, and converted to valuable products, the whole process of lignocellulose utilization (bio-refining) could be economically feasible. The scope of this study was to review and evaluate all of the presently available methods for separating the fractions of lignocellulosic biomasses, and for utilizing them. Over one hundred publications were reviewed from the fields of biotechnology, food chemistry, and chemical technology to collect all processes for lignocellulose utilization.