Bioethanol production from secondary bioresources of the pulp and paper industry

Abstract

The prospects for obtaining bioethanol based on secondary bioresources of the pulp and paper industry are discussed in order to close economic cycles. The transformation of sugars of acidic hydrolyzate of deciduous wood into bioethanol by batch culture of a selected strain of the yeast Saccharomyces cerevisiae with a combination of various xylose-assimilating yeasts was studied. The ethanol yield from hexose`s part was 46% from fermented sugars, its concentration reached to 9,0±0,6 g l-1. The use of pentose sugars under microaerobic conditions (concentration of dissolved oxygen 0.5-3.0%) gave the efficiency of ethanol production up to 26.7 - 35.5% from fermented sugars. The ethanol concentration in terms of the pentose`s fraction was 3.9-4.5 g l-1 (the yeast Pachysolen tannophilus); 5.2 g l-1 (the yeast Candida tropicalis); 5.6 g l-1 (the yeast Candida shehatae). The total amount of ethanol obtained from both hexose and pentose parts after distillation was 4.2-4.6 g (5.2-5.7 ml) with alcohol by volume 96%.