BIOPEP-UWM, a peptide database, contains 5128 peptides from a myriad of resources. Five listed peptides are Angiotensin-I-converting enzyme (ACE-1; EC3.4.15.1) inhibitory peptides derived from a red alga, while two from Chlorella vulgaris have anti-cancer and antioxidative bioactivities. Herein, we describe a process combining hydrolysis with two enzymes, Alcalase and Viscozyme, and filtration to generate protein-rich, bioactive peptide-containing hydrolysates from mixed species of Chlorella sp. and Scenedesmus sp. The potential of generated algal hydrolysates to act as food ingredients was determined by assessment of their techno-functional (foaming, emulsification, solubility, water holding, and oil holding capacity) properties. Bioactive screening of hydrolysates in vitro combined with mass spectrometry (MS) and in silico predictions identified bioactive and functional hydrolysates and six novel peptides. Peptides derived from Chlorella mix have the sequences YDYIGNNPAKGGLF and YIGNNPAKGGLF with predicted anti-inflammatory (medium confidence) and umami potential. Peptides from Scenedesmus mix have sequences IEWYGPDRPKFL, RSPTGEIIFGGETM, TVQIPGGERVPFLF, and IEWYGPDRPKFLGPF with predicted anti-inflammatory, anti-diabetic, and umami attributes. Such microalgal hydrolysates could provide essential amino acids to consumers as well as tertiary health benefits to improve human global health.

Although microalgae exploitation is very promising, process sustainability is undermined by biomass production and harvesting. Among the various bottlenecks of the production process, particular attention should be paid to the water footprint. Indeed, a huge volume of water is required in microalgae production. Water reuse can support both the water footprint and medium cost reduction, saving water and unconverted substrates. The present study reports preliminary results regarding the utilization of a water reuse strategy for two Chlorophyta microalgae under batch conditions. Growth parameters and chlorophyll content are monitored and the optimal amount of reused medium is assessed. The results show that 70% of the medium can be reused with no loss of specific growth rate and chlorophyll fraction for Pseudococcomyxa simplex in three consecutive batch cultivations. By contrast, a significant decline in Chlorella vulgaris growth was observed after the first cultivation in reused medium, across all tested conditions.

BIOPEP-UWM, a peptide database, contains 5128 peptides from a myriad of resources. Five listed peptides are Angiotensin-I-converting enzyme (ACE-1; EC3.4.15.1) inhibitory peptides derived from a red alga, while two from Chlorella vulgaris have anti-cancer and antioxidative bioactivities. Microalgae are a future protein source and support several UN sustainable development goals (SDGs) including, 2, Zero Hunger and 3, Good Health and Well-being and 13, Climate Action. Herein, we describe a process combining hydrolysis and filtration to generate protein-rich, bioactive peptide-containing hydrolysates from mixed species of Chlorella sp. and Scenedesmus sp. The potential of generated algal hydrolysates to act as food ingredients was determined by assessment of their techno-functional (foaming, emulsification, solubility, water holding and oil holding capacity) properties. Bioactive screening of hydrolysates in vitro combined with mass spectrometry (MS), and in silico, predictions identified bioactive and functional hydrolysates and six novel peptides. Peptides derived from Chlorella sp. have the sequences YDYIGNNPAKGGLF and YIGNNPAKGGLF with predicted anti-inflammatory (medium confidence) and umami potential. Peptides from Scenedesmus sp. have sequences IEWYGPDRPKFL, RSPTGEIIFGGETM, TVQIPGGERVPFLF and IEWYGPDRPKFLGPF with predicted anti-inflammatory, anti-diabetic and umami attributes. Such microalgal hydrolysates could provide essential amino acids to consumers as well as tertiary, health benefits to improve human global health.

Microalgae cultivation for biotechnological purposes is an expanding field. Their cultivation is usually performed on a liquid culture medium and require the presence of an energy source. Culture media are water-salt solutions containing nitrogen, sulfur, phosphate sources, with trace of transition metals. Light source supplies energy through photosynthesis process, resulting in metabolic reactions and cell growth. Thanks to the huge number of existing species and their diversity, it is possible to exploit alternative water sources with chemical and physical properties far from the commonly used freshwater media. Among these, oilfield or formation waters (AFW) are saline wastewater produced during oil drilling. They represent over 95 % of the total fluids collected from gas and oil wells during fuel extraction. This study exploits the adaptation capability of a Galdieria sulphuraria strain in different salinity conditions to build up a more feasible microalgae-based platform. Batch cultivation of G. sulphuraria was evaluated in a range from 0 to 20 g/L NaCl in terms of growth rate, metabolite content, photophysiology, and intracellular redox state. Moreover, the same strain has been tested for artificial formation water growth in semicontinuous cultivation mode. In these condition, NaCl preadaptation effect has been assessed too. Results clearly demonstrate that biomass composition is influenced from medium salinity. Strains preadapted in 0 to 20 g/L range of NaCl salinity show almost same cell growth profile and a slightly different ratio between lipids, carbohydrates, and proteins. Pigments content and photophysiology point out that variations of osmotic pressure and ionic strength in medium affect Photosystem II (PSII). Regulation of light harvesting is necessary to trigger metabolism shift toward synthesis of metabolites required in the adaptation process.