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Characterization and biotechnological potential of extracellular polysaccharides synthesized by Alteromonas strains isolated from French Polynesia marine environments

Publication . Concórdio-Reis, Patrícia; Delgado Alves, Vitor; Moppert, Xavier; Guezennec, Jean; Freitas, Filomena; Reis, Maria A.M.

Marine environments comprise almost three quarters of Earth’s surface, representing the largest ecosystem of our planet. The vast ecological and metabolic diversity found in marine microorganisms suggest that these marine resources have a huge potential as sources of novel commercially appealing biomolecules, such as exopolysaccharides (EPS). Six Alteromonas strains from different marine environments in French Polynesia atolls were selected for EPS extraction. All the EPS were heteropolysaccharides composed of different monomers, including neutral monosaccharides (glucose, galactose, and mannose, rhamnose and fucose), and uronic acids (glucuronic acid and galacturonic acid), which accounted for up to 45.5 mol% of the EPS compositions. Non-carbohydrate substituents, such as acetyl (0.5–2.1 wt%), pyruvyl (0.2–4.9 wt%), succinyl (1–1.8 wt%), and sulfate (1.98–3.43 wt%); and few peptides (1.72–6.77 wt%) were also detected. Thermal analysis demonstrated that the EPS had a degradation temperature above 260 C, and high char yields (32–53%). Studies on EPS functional properties revealed that they produce viscous aqueous solutions with a shear thinning behavior and could form strong gels in two distinct ways: by the addition of Fe2+, or in the presence of Mg2+, Cu2+, or Ca2+ under alkaline conditions. Thus, these EPS could be versatile materials for different applications

2021Journal article

Open access

Co-processed olive oils with Thymus mastichina L. - New product optimization

Publication . Peres, Fátima; Roldão, Marta; Mourato, Miguel; Louro Martins, Luisa; Ferreira-Dias, S.

Olive co-processing consists of the addition of ingredients either in the mill or in the malaxator. This technique allows selecting the type of olives, the ingredients with the greatest flavoring and bioactive potential, and the technological extraction conditions. A new product—a gourmet flavored oil—was developed by co-processing olives with Thymus mastichina L. The trials were performed using overripe fruits with low aroma potential (cv. ‘Galega Vulgar’; ripening index 6.4). Experimental conditions were dictated by a central composite rotatable design (CCRD) as a function of thyme (0.4-4.6%, w/w) and water (8.3-19.7%, w/w) contents used in malaxation. A flavored oil was also obtained by adding 2.5% thyme during milling, followed by 14% water addition in the malaxator (central point conditions of CCRD). The chemical characterization of the raw materials, as well as the analysis of the flavored and unflavored oils, were performed (chemical quality criteria, sensory analysis, major fatty acid composition, and phenolic compounds). Considering chemical quality criteria, the flavored oils have the characteristics of “Virgin Olive Oil” (VOO), but they cannot have this classification due to legislation issues. Flavored oils obtained under optimized co-processing conditions (thyme concentrations > 3.5-4.0% and water contents varying from 14 to 18%) presented higher phenolic contents and biologic value than the non-flavored VOO. In flavored oils, thyme flavor was detected with high intensity, while the defect of “wet wood”, perceived in VOO, was not detected. The flavored oil, obtained by T. mastichina addition in the mill, showed higher oxidative stability (19.03 h) than the VOO and the co-processed oil with thyme addition in the malaxator (14.07 h), even after six-month storage in the dark (16.6 vs. 10.3 h)

2021Journal article

Open access

Influence of dietary Spirulina inclusion and lysozyme supplementation on the longissimus lumborum muscle proteome of newly weaned piglets

Publication . Ribeiro, David M.; Martins, Cátia F.; Kules, Josipa; Horvatic, Anita; Guillemin, Nicolas; Freire, João; Eckersall, P. David; Almeida, André M.; Prates, José A.M.

Arthrospira platensis (Spirulina) is a microalga with a high content of crude protein. Its recalcitrant cell wall limits the accessibility of the animal endogenous enzymes to its intracellular nutrients. Enzymatic supplementation aiming to degrade cell walls could benefit microalgae digestibility. The objective of this study was to evaluate the impact of dietary Spirulina and lysozyme supplementation over the muscle proteome of piglets during the post-weaning stage. Thirty piglets were randomly distributed among three diets: control (no microalga), SP (10% Spirulina) and SP+L (10% Spirulina + 0.01% lysozyme). After 4 weeks, they were sacrificed and samples of the longissimus lumborum muscle were taken. The muscle proteome was analysed using a Tandem Mass Tag (TMT)-based quantitative approach. A total of 832 proteins were identified. Three comparisons were computed: SP vs Ctrl, SP+L vs Ctrl and SP+L vs SP. They had ten, four and twelve differentially abundant proteins. Glycogen metabolism and nutrient reserves utilization are seemingly increased in the SP piglets. Structural muscle protein synthesis increased, causing higher energy requirements in SP+L piglets. Our results demonstrate the usefulness of proteomics to disclose the effect of dietary microalgae, whilst unveiling putative mechanisms derived from lysozyme supplementation. Data are available via ProteomeXchange with identifier PXD024083

2021Journal article

Open access

Influence of dietary Spirulin inclusion and lysozyme supplementation on the longissimus lumborum muscle proteome of newly weaned piglets

Publication . Ribeiro, D. M.; Martins, Cátia Falcão; Kules, Josipa; Horvatic, Anita; Guillemin, Nicolas; Freire, João; Eckersall, P. David; Almeida, André; Prates, José A.M

Arthrospira platensis (Spirulina) is a microalga with a high content of crude protein. It has a recalcitrant cell wall that limits the accessibility of the animal endogenous enzymes to its intracellular nutrients. Enzymatic supplementation aiming to degrade cell walls could benefit microalgae digestibility. The objective of this study was to evaluate the impact of dietary Spirulina and lysozyme supplementation over the muscle proteome of piglets during the post-weaning stage. Thirty piglets were randomly distributed among three diets: control (no microalga), SP (10% Spirulina) and SP + L (10% Spirulina +0.01% lysozyme). After 4 weeks, they were sacrificed and samples of the longissimus lumborum muscle were taken. The muscle proteome was analysed using a Tandem Mass Tag (TMT)-based quantitative approach. A total of 832 proteins were identified. Three comparisons were computed: SP vs Ctrl, SP + L vs Ctrl and SP + L vs SP. They had ten, four and twelve differentially abundant proteins. Glycogen metabolism and nutrient reserves utilization are increased in the SP piglets. Structural muscle protein synthesis increased, causing higher energy requirements in SP + L piglets. Our results demonstrate the usefulness of proteomics to disclose the effect of dietary microalgae, whilst unveiling putative mechanisms derived from lysozyme supplementation. Data available via ProteomeXchange with identifier PXD024083. Significance: Spirulina, a microalga, is an alternative to conventional crops which could enhance the environmental sustainability of animal production. Due to its recalcitrant cell wall, its use requires additional measures to prevent anti-nutritional effects on the feeding of piglets in the post-weaning period, during which they endure post-weaning stress. One of such measures could be CAZyme supplementation to help degrade the cell wall during digestion. Muscle proteomics provides insightful data on the effect of dietary microalgae and enzyme activity on piglet metabolism.

2021-07-30Journal article

Open access

Enhanced biomethane production by co-digestion of mixed sewage sludge and dephenolised two-phase olive pomace

Publication . Fragoso, Rita; Henriques, Ana Catarina; Ochando-Pulido, Javier; Smozinski, Nicole; Duarte, Elizabeth

In this study, co-digestion of mixed sewage sludge from a wastewater treatment plant (WWTP) and partially dephenolised twophase olive pomace (DOP) as a co-substrate was addressed with the aim of improving the biodigestibility of both substrates. The introduction of DOP into WWTP anaerobic digester facilities could significantly increase biomethane production and enhance the sustainability of both activities. An improvement in the system’s performance was supported by stability parameters: total alkalinity increased and stabilised with the addition of 5% v/v DOP, and the specific energy loading rate was maintained at 0.177 ± 0.03 d−1, which indicated better buffer capacity and stability in the bioreactor, and the possibility of enhancing the organic loading rate. In terms of average daily biogas production rate, an increase of 39% was achieved, up to 0.39 ± 0.11 L L−1d−1. Moreover, there was a 40% and 37% improvement in specific methane production and methane production rate, respectively, up to 0.28 ± 0.02 L CH4 g TVS −1 and 0.26 ± 0.08 L L−1d−1. In addition, the proposed strategy leads to an energy saving of 20,328.6 kWh year−1 at the WWTP as a result of the electric energy production surplus, corresponding to an annual saving of €3293.23

2021Journal article

Open access