Associate Laboratory on Biotechnology, Bioengineering and microELectromechanical Systems

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Publications

Comparison of different pretreatment processes envisaging the potential use of food waste as microalgae substrate

Publication . Marques, Fabiana; Pereira, Francisco; Machado, Luís; Martins, Joana T.; Pereira, Ricardo N.; Costa, Monya; Genisheva, Zlatina; Pereira, Hugo; Vicente, António A.; Teixeira, José A.; Geada, Pedro

A significant fraction of the food produced worldwide is currently lost or wasted throughout the supply chain, squandering natural and economic resources. Food waste valorization will be an important necessity in the coming years. This work investigates the ability of food waste to serve as a viable nutritional substrate for the heterotrophic growth of Chlorella vulgaris. The impact of different pretreatments on the elemental composition and microbial contamination of seven retail food waste mixtures was evaluated. Among the pretreatment methods applied to the food waste formulations, autoclaving was able to eliminate all microbial contamination and increase the availability of reducing sugars by 30%. Ohmic heating was also able to eliminate most of the contaminations in the food wastes in shorter time periods than autoclave. However, it has reduced the availability of reducing sugars, making it less preferable for microalgae heterotrophic cultivation. The direct utilization of food waste containing essential nutrients from fruits, vegetables, dairy and bakery products, and meat on the heterotrophic growth of microalgae allowed a biomass concentration of 2.2 x 108 cells center dot mL-1, being the culture able to consume more than 42% of the reducing sugars present in the substrate, thus demonstrating the economic and environmental potential of these wastes.

2024-04Journal article

Open Access

Optimization of Pavlova gyrans biomass production and the fatty acid profile using a twostep approach

Publication . Maciel, Filipe; Couto, Daniela; Geada, Pedro; Pereira, Hugo; Teixeira, José; Domingues, M. Rosário; Silva, Joana; Vicente, António

This work aimed to optimize and characterize the biomass production of Pavlova gyrans through a sequential multivariate approach. Among seventeen cultivation parameters, light intensity, NaNO3, and CuSO45H(2)O were identified as the most significative factors (p < 0.10) for biomass productivity. Together with NaH2PO4H2O, these variables were further studied in order to maximize the biomass production of P. gyrans, with the optimum growth conditions identified as 700 mu mol(photons) m(-2) s(-1) light intensity, 1500 mg L-1 NaNO3, 6 mu g L-1 CuSO45H(2)O and 40 mg L-1 NaH2PO4H2O. These conditions allowed a 3.8-fold increase in biomass production (2.26 g AFDW per L) and improved the biochemical profile (p < 0.05) when compared with the control (Walne's medium). Namely, it was increased the contents of protein (from 10.59 to 30.76% DW), PUFAs (from 37.13 to 47.11% TFA), n - 3 FAs (26.49 to 38.27% TFA), and DHA (from 5.73 to 10.33% TFA). The nutritional value of the microalga (p < 0.05) was also improved, decreasing its atherogenic (AI - from 1.34 to 0.93) and thrombogenic (TI - from 0.45 to 0.24) indices, while the hypocholesterolemic index (HI) increased from 0.96 to 1.63. This work highlights the importance of different growth conditions in P. gyrans, playing a relevant role in the large-scale implementation of this microalga with beneficial nutritional composition for human consumption.

2023Journal article

Open Access