Valorization of raw brewers' spent grain through the production of volatile fatty acids.

Authors :: Ribau Teixeira M
Guarda EC
Freitas EB
Galinha CF
Duque AF
Reis MAM
Source :: New biotechnology [N Biotechnol] 2020 Jul 25; Vol. 57, pp. 4-10. Date of Electronic Publication: 2020 Jan 29.
Publication Year :: 2020
Abstract: This work is focused on production of volatile fatty acids (VFA) through anaerobic digestion (AD) using raw (without pre-treatment) brewers' spent grain (BSG) as feedstock. VFAs are by-products from AD of organic wastes with wide potential industrial application in bioplastic production. A long term fed batch stirred-tank reactor was operated and the impact of three hydraulic retention times (HRT) and two organic loading rates (OLR) on VFA production was assessed. Results showed clearly that AD of raw BSG is possible without a pre-treatment step. The maximum volumetric VFA productivity of 91.3 ± 9.1 mgCODL <superscript>-1</superscript> h <superscript>-1</superscript> and VFA concentration of 24.9 ± 2.6 g L <superscript>-1</superscript> were obtained for 16 days of HRT and 16 gTS <subscript>in</subscript> L <superscript>-1</superscript> d <superscript>-1</superscript> of OLR. This is the highest value of VFA concentration so far reported for BSG. Propionic, acetic and butyric acids were the main VFAs produced. Community identification by FISH and its correlation with process parameters was performed by principal component analysis.<br /> (Copyright © 2020 Elsevier B.V. All rights reserved.)

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