Browsing by Author "Duque, Anouk F."
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- Valorization of brewery waste through Polyhydroxyalkanoates production supported by a metabolic specialized microbiomePublication . Carvalheira, Mónica; Amorim, Catarina L.; Oliveira, Ana Catarina; Guarda, Eliana C.; Costa, Eunice; Ribau Teixeira, Margarida; Castro, Paula M. L.; Duque, Anouk F.; Reis, Maria A. M.Raw brewers’ spent grain (BSG), a by-product of beer production and produced at a large scale, presents a composition that has been shown to have potential as feedstock for several biological processes, such as polyhydroxyalkanoates (PHAs) production. Although the high interest in the PHA production from waste, the bioconversion of BSG into PHA using microbial mixed cultures (MMC) has not yet been explored. This study explored the feasibility to produce PHA from BSG through the enrichment of a mixed microbial culture in PHA-storing organisms. The increase in organic loading rate (OLR) was shown to have only a slight influence on the process performance, although a high selectivity in PHA-storing microorganisms accumulation was reached. The culture was enriched on various PHA-storing microorganisms, such as bacteria belonging to the Meganema, Carnobacterium, Leucobacter, and Paracocccus genera. The enrichment process led to specialization of the microbiome, but the high diversity in PHA-storing microorganisms could have contributed to the process stability and efficiency, allowing for achieving a maximum PHA content of 35.2 ± 5.5 wt.% (VSS basis) and a yield of 0.61 ± 0.09 CmmolPHA/CmmolVFA in the accumulation assays. Overall, the production of PHA from fermented BSG is a feasible process confirming the valorization potential of the feedstock through the production of added-value products.
- Valorization of raw brewers' spent grain through the production of volatile fatty acidsPublication . Ribau Teixeira, Margarida; Guarda, Eliana C.; Freitas, Elisabete B.; Galinha, Claudia F.; Duque, Anouk F.; Reis, Maria A. M.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 pretreatment step. The maximum volumetric VFA productivity of 91.3 +/- 9.1 mgCODL(-1) h(-1) and VFA concentration of 24.9 +/- 2.6 g L-1 were obtained for 16 days of HRT and 16 gTS(in)L(-1)d(-1) 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.