Browsing by Author "Galinha, Claudia F."
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- Acidogenic fermentation of brewers’ spent grain monitored through two-dimensional fluorescence spectroscopyPublication . Guarda, Eliana C.; Costa, Eunice; Gil, Cátia; Amorim, Catarina L.; Galinha, Claudia F.; Duque, Anouk F.; Castro, Paula M. L.; Reis, Maria A. M.Biological systems are commonly controlled and monitored through offline and time-consuming tools, which often impairs an effective and real-time response to counteract system disturbances. The feasibility of using two-dimensional (2D) fluorescence spectroscopy as a non-invasive, non-destructive, and real-time procedure to monitor the acidogenic fermentation of brewer’s spent grain (BSG) in a granular sludge reactor was evaluated. For that, the effect of pH fluctuations on the system response was used as a model to ascertain the 2D fluorescence spectroscopy applicability to monitor the process performance, namely, to predict the fermentation products (FP) and the soluble protein (SProt) concentrations in the effluent stream through mathematical analysis. The pH fluctuations over the course of the reactor’s operation altered the granules’ microbiome composition, leading to different effluent FP profiles. Fluorescence excitation–emission matrices (EEMs) were used with projection to latent structures (PLS) modeling to predict the FP and SProt concentrations in the effluent with average errors below 0.75 and 0.43 g L–1, respectively. Both models were able to capture the tendency of the data even when the accuracy of prediction was not so high. The combined approach of using 2D fluorescence spectroscopy and mathematical analysis seemed promising for real-time monitoring of the acidogenic fermentation of complex substrates.
- Polyhydroxyalkanoates production from a waste-derived feedstock driven by the reactor operating conditions: the role of biomass microbiome and its reactivation capacityPublication . Guarda, Eliana C.; Amorim, Catarina L.; Pasculli, Gabriele; Castro, Paula M. L.; Galinha, Claudia F.; Duque, Anouk F.; Reis, Maria A. M.In the last years, the production of plastics at large-scale has been an issue of great concern due to their environmental and health impacts. Biobased and biodegradable plastics, such as polyhydroxyalkanoates (PHA), have emerged as a possible more ecological and sustainable alternative to those conventional plastics. PHA can be produced by mixed microbial cultures (MMC) from waste-based feedstocks. This work aimed to maximize the PHA production from fermented brewer's spent grain by selecting an efficient PHA-accumulating MMC, applying different organic loading rates (OLR, 45 or 60 CmmolFP/(L.d)) and sludge retention times (SRT, 4 or 2 days). Additionally, the biomass reactivation capacity after storage was evaluated. The global PHA productivity depends on the operating conditions, achieving its maximum (3.55 ± 0.8 gPHA/(L.d)) at the highest OLR and SRT tested. After storage, the global PHA productivity was similar to the one achieved before the starvation period. Depending on the operating conditions, the microbiome has its own bacterial composition signature containing various PHA-producers genera (e.g., Acidovorax, Amaricoccus, Brevundimonas, Leucobacter, Leadbetterella and Thauera) that persisted over time, albeit at different relative abundancies. A comprehensive overview of PHA production with data on system performance and microbiome is presented, which thereby can further contribute to the upscale of such valorisation processes.