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BioMed Research International
Volume 2015 (2015), Article ID 176371, 10 pages
http://dx.doi.org/10.1155/2015/176371
Research Article

Ethanol and Protein from Ethanol Plant By-Products Using Edible Fungi Neurospora intermedia and Aspergillus oryzae

1Swedish Centre for Resource Recovery, University of Borås, 501 90 Borås, Sweden
2Faculty of Forestry, University of West Hungary, Sopron 9400, Hungary

Received 29 May 2015; Revised 10 October 2015; Accepted 15 October 2015

Academic Editor: Michael E. Kornaros

Copyright © 2015 Veronika Bátori et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Feasible biorefineries for production of second-generation ethanol are difficult to establish due to the process complexity. An alternative is to partially include the process in the first-generation plants. Whole stillage, a by-product from dry-mill ethanol processes from grains, is mostly composed of undegraded bran and lignocelluloses can be used as a potential substrate for production of ethanol and feed proteins. Ethanol production and the proteins from the stillage were investigated using the edible fungi Neurospora intermedia and Aspergillus oryzae, respectively. N. intermedia produced 4.7 g/L ethanol from the stillage and increased to 8.7 g/L by adding 1 FPU of cellulase/g suspended solids. Saccharomyces cerevisiae produced 0.4 and 5.1 g/L ethanol, respectively. Under a two-stage cultivation with both fungi, up to 7.6 g/L of ethanol and 5.8 g/L of biomass containing 42% (w/w) crude protein were obtained. Both fungi degraded complex substrates including arabinan, glucan, mannan, and xylan where reductions of 91, 73, 38, and 89% (w/v) were achieved, respectively. The inclusion of the current process can lead to the production of 44,000 m3 of ethanol (22% improvement), around 12,000 tons of protein-rich biomass for animal feed, and energy savings considering a typical facility producing 200,000 m3 ethanol/year.