The present invention relates to a process for enriching a biomass of microalgae of the Thraustochytrium genus with DHA and with arginine and glutamic acid amino acids, characterized in that it comprises a step aimed at limiting the rate of growth of the microalga while at the same time maintaining or continuously introducing a source of nitrogen in or into the fermentation medium.

The invention relates to a peptide isolate isolated from a biomass of protein-rich microalgae, characterized in that it comprises: soluble peptides with a molecular weight of between 1 and 20 kDa, a protein content expressed as N.6.25 of more than 95%, essentially arginine and glutamic acid.

The invention relates to a method for preparing a lipid-rich microalgal flour, which comprises the following steps: (a) providing a microalgal biomass comprising more than 50% of lipids by dry weight of biomass; (b) lyzing the microalgae, (c) concentrating the microalgal lyzate to a solids content of more than 25% by weight, preferably to a solids content of between 35% and 50% by weight, (d) applying a heat treatment to the lyzate thus concentrated, (e) homogenizing at high pressure the lyzate obtained in step (d), so as to obtain a stable emulsion, (f) drying said emulsion to obtain the microalgal flour.

The invention pertains to a method for synthesizing a product of interest by culturing a microalgal cell producing the product of interest in the dark in a culture medium comprising an organic acid as a fixed carbon source, wherein the microalgal cell is a facultative heterotroph. The product of interest can be a microalgal biomass, a pigment, terpene, recombinant molecule, biogas, or a precursor thereof. In an embodiment, the culture medium comprises urea as a primary source of nitrogen. In one embodiment, the microalgal cell belongs to the order Chlamydomonadales. A method of identifying and isolating a microalgal cell having a preferred characteristic that is suitable for synthesis of a product of interest is also provided, the method comprising identifying and isolating a non-mutagenized or recombinant microalgal cell from a microalgal culture using a fluorescence activated cell sorting technique and/or a phototaxic response.

The invention pertains to a method for synthesizing a product of interest by culturing a microalgal cell producing the product of interest in the dark in a culture medium comprising an organic acid as a fixed carbon source, wherein the microalgal cell is a facultative heterotroph. The product of interest can be a microalgal biomass, a pigment, terpene, recombinant molecule, biogas, or a precursor thereof. In an embodiment, the culture medium comprises urea as a primary source of nitrogen. In one embodiment, the microalgal cell belongs to the order Chlamydomonadales. A method of identifying and isolating a microalgal cell having a preferred characteristic that is suitable for synthesis of a product of interest is also provided, the method comprising identifying and isolating a non-mutagenized or recombinant microalgal cell from a microalgal culture using a fluorescence activated cell sorting technique and/or a phototaxic response.

The invention relates to a method for fractionating the components of a biomass of protein-rich microalgae of the genus Chlorella, characterized in that it comprises the following steps: providing a microalgal biomass produced by fermentation, optionally, washing the biomass so as to eliminate the interstitial soluble compounds, thermal permeabilization of the biomass at a temperature of between 50 and 150° C., preferably 100 and 150° C., for a duration of between 10 seconds and 5 minutes, preferably for a duration of between 5 seconds and 1 minute, separation between the biomass thus permeabilized and the soluble fraction by a centrifugation technique, more particularly multistage centrifugation, optionally, recovery and clarification of the soluble fraction obtained in this way by microfiltration so as to remove residual insoluble substances therefrom, separation of the preceding soluble fraction by precipitation, so as to obtain a peptide isolate and a peptide concentrate.

A method of cultivating algal cells of an algae belonging to a class selected from Chlorophyceae, Euglenophyceae, Bacillariophyceae and Haptophyceae includes: irradiating the algal cells with an artificial light having a ratio of (i) photon flux density in a wavelength range of 520-630 nm to (ii) photosynthetic photon flux density, that is 65% or more; and measuring a cell size of the algal cells. Irradiation and non-irradiation of the algal cells with the artificial light are switched, or the photon flux density in the wavelength range of 520-630 nm is changed, according to the measured cell size.

A method of cultivating algal cells of an algae belonging to a class selected from Chlorophyceae, Euglenophyceae, Bacillariophyceae and Haptophyceae includes: irradiating the algal cells with an artificial light having a ratio of (i) photon flux density in a wavelength range of 520-630 nm to (ii) photosynthetic photon flux density, that is 65% or more; and measuring a cell size of the algal cells. Irradiation and non-irradiation of the algal cells with the artificial light are switched, or the photon flux density in the wavelength range of 520-630 nm is changed, according to the measured cell size.

A genetically modified phototrophic cell for in-vivo production of hydrogen. The phototrophic cell has been genetically modified to the effect that a) at least one of the native photosystem I components has been deleted, b) the native hydrogenase has been deleted, and c) at least one fusion protein is expressed, comprising i. a hydrogenase or hydrogenase component and ii. at least one PSI component, with the proviso that the PSI is complemented by expression of the at least one fusion protein, and the hydrogenase component itself, or together with at least one further hydrogenase component expressibly introduced into the cell, has hydrogenase activity.

A method and system is provided for increasing lipids, biomass, and metabolite yields of a microalgae culture of cells and other organisms with conserved metabolic pathways compared to an untreated culture or organism when maintained under normal conditions. The method includes irradiating with electromagnetic ionizing radiation to induce rapid and reproducible hormetic metabolic activation in the organism cells. In an embodiment, the irradiation can be applied in a exponential or stationary phase of microalgae growth. The hormetic effect involves up-regulation of expression of lipid metabolism genes encoding enzymes that are involved in the biosynthesis of lipids with accumulation of energy reserves in the form of lipids and/or accumulation of other metabolites. The method can be implemented in a system that can interface with existing microalgae cultivation platforms, standard microalgae cultivation conditions, alongside standard microalgae culture types, and similarly with organisms with conserved metabolic pathways in their growth substrates.