Marine microalgae and cyanobacteria are sources of diverse bioactive compounds with potential biotechnological applications in food, feed, nutraceutical, pharmaceutical, cosmetic and biofuel industries. In this study, five microalgae, Nitzschia sp. S5, Nanofrustulum shiloi D1, Picochlorum sp. D3, Tetraselmis sp. Z3 and Tetraselmis sp. C6, and the cyanobacterium Euhalothece sp. C1 were isolated from the Adriatic Sea and characterized regarding their growth kinetics, biomass composition and specific products content (fatty acids, pigments, antioxidants, neutral and polar lipids). The strain Picochlorum sp. D3, showing the highest specific growth rate (0.009 h⁻¹), had biomass productivity of 33.98 ± 0.02 mg L⁻¹ day⁻¹. Proteins were the most abundant macromolecule in the biomass (32.83–57.94%, g g⁻¹). Nanofrustulum shiloi D1 contained significant amounts of neutral lipids (68.36%), while the biomass of Picochlorum sp. D3, Tetraselmis sp. Z3, Tetraselmis sp. C6 and Euhalothece sp. C1 was rich in glycolipids and phospholipids (75%). The lipids of all studied microalgae predominantly contained unsaturated fatty acids. Carotenoids were the most abundant pigments with the highest content of lutein and neoxanthin in representatives of Chlorophyta and fucoxanthin in strains belonging to the Bacillariophyta. All microalgal extracts showed antioxidant activity and antimicrobial activity against Gram-negative E. coli and S. typhimurium and Gram-positive S. aureus.

Marine microalgae often live in a fluctuating environment including a decrease in salinity caused by global warming induced sea ice melting and freshwater inflows. Under conditions of fluctuating salinity, microalgae have evolved a variety of survival mechanisms such as lipid accumulation and remodeling. The purpose of this study was to investigated the membrane lipid remodeling of the marine green microalgaDunaliella tertiolectaas a short-term acclimation mechanism in response to hyposalinity (20 and 3 PSU) with respect to growth at optimal salinity (38 PSU). We identified 34 lipid species belonging to seven polar lipid classes.Dunaliella tertiolectaaccumulates cell lipids and remodels polar lipid classes and their fatty acids composition as response to hypoosmotic stress at 3 PSU. We found that the unsaturation of most polar lipids decreases overall, indicating decreased membrane fluidity and altered permeability, whereas shortening the length of fatty acids of polar lipids is not one of the strategies ofD. tertiolectato cope with the decrease in salinity. Increase in relative content (%) and unsaturation of monogalactosyldiacylglycerols (MGDG) and decrease in relative content (%) and unsaturation of phosphatidylglycerols (PG), suggesting changes in photosynthetic membranes of thylakoids at 20 and 3 PSU. At a very low salinity of 3 PSU, the relative content (%) of phosphatidylinositols (PI) increases, suggesting increased lipid trafficking and signaling in the cells. These changes are statistically significant and we hypothesize thatD. tertiolectais genetically adapted to withstand large salinity fluctuations through polar lipid composition.

The assimilation of inorganic nutrients by phytoplankton strongly depends on environmental conditions such as the availability of nitrogen and temperature, especially warming. The acclimation or adaptation of different species to such changes remains poorly understood. Here, we used a multimethod approach to study the viability and physiological and biochemical responses of the marine diatom Chaetoceros pseudocurvisetus to different temperatures (15, 25, and 30 °C) and different N:P ratios. Nitrogen limitation had a greater effect than high temperature on cell growth and reproduction, leading to a marked elongation of setae, decreased phosphorus assimilation, increased lipid accumulation, and decreased protein synthesis. The elongation of setae observed under these conditions may serve to increase the surface area available for the uptake of inorganic and/or organic nitrogen. In contrast, high temperatures (30 °C) had a stronger effect than nitrogen deficiency on cell death, nitrogen assimilation, chlorophyll a accumulation, the cessation of setae formation, and cell lipid remodelling. Significant changes in thylakoid lipids were observed in cells maintained at 30 °C, with increased levels of digalactosyldiacylglycerol and sulfoquinovosyldiacylglycerol. These changes may be explained by the role of galactolipids in thylakoid membrane stabilization during heat stress.

Driven by the bakery industry urge to satisfy consumer demand for fresh, diverse and high quality bakery products, we investigated the influence of barley sourdough and vacuum cooling on shelf life quality of partially baked bread stored in modified atmosphere packaging at ambient conditions. Barley sourdough was fermented with Lactobacillus reuteri (DSM 20016, F275). Partially baked bread with sourdough was microbiologically acceptable during 30 days of storage, while bread without sourdough had detectable mould on the 30th day. Stored bread samples were rebaked after 1, 8, 15, 22 and 30 days to determine moisture content, physical and sensorial properties. Moisture loss (5%) was detected on the 15th day, after which it remained stable until the end of investigated storage period. Nevertheless, textural quality of stored bread continuously declined due to crumb firming. Bread flavour did not change during mould-free storage time. The principal component analysis identified major differences in the flavour of sour and control bread, also in crumb firmness and moisture content of samples. This study indicates the positive role of barley sourdough fermented with L. reuteri in improving crumb texture for at least 15 days, and ensuring mould- and bacteria-free partially baked bread for 30 days. Vacuum cooling combined with sourdough improved bread shape, porosity, and reduced sour taste, crust colouring and crumbliness. Hence, it can successfully extend shelf life quality of partially baked bread in modified atmosphere packaging.

Two main parameters that structure the marine ecosystem by affecting species distribution, abundance, community structure, timing of major life cycle events, and trophic state of the ecosystem are temperature and nutrient availability. Faced with climate change, eukaryotic plankton cope at multiple levels through physiological accommodation, adaptive evolution, shift in time and/or space of habitat, and/or community responses. Thirty‐two years of our phytoplankton research indicate that Chaetoceros curvisetus/pseudocurvisetus adjust to climate change more successfully than the majority of the accompanying phytoplankton taxa in the mesotrophic part of the NW Adriatic Sea, the Mediterranean. While the abundance of the entire accompanying phytoplankton community has decreased significantly since 2003 (the period of the northern Adriatic warming and oligotrophication) compared to the previous period (1986–2003), the abundance of C. curvisetus/pseudocurvisetus remained unchanged, while its contribution to the community increased significantly. Accommodation strategies include a change in the timing of high abundance and blooms in the surface layer and successful blooming in the deeper layers during warm months. Apart from the observed in situ accommodation, physiological acclimation to warming may involve changes in photosynthesis, respiration, growth, and cell biochemistry. Here, we conducted laboratory experiments with C. pseudocurvisetus to investigate how warming affects its biochemical response through the fatty acid remodeling of phospholipid classes. Long‐term field observations and short‐term laboratory experiments suggest that marine diatoms C. curvisetus/pseudocurvisetus are potential global winners with the ability to acclimate/adapt to climate change.