Abstract: Provided are compositions and methods for sustainable cultivation of algae for biomass, biofuel and bioproduct production, preferably with minimal addition of exogenous nutrients, comprising co-cultivating at least one algal species with at least one aerobic bacterial species and at least one diazotroph (or, in certain embodiments, cultivation of at least one algal species with at least one diazotroph) under continuous sustainable symbiotic conditions, wherein a significant proportion of the macronutrients derive from endogenous decomposed algal and bacterial cells. Certain aspects provide continuous symbiotic diazotroph-attenuated nitrogen stress co-cultivation, wherein a continuous, balanced attenuated nitrogen-stress response provides for adequate sustained algal growth, while yet preserving advantages of algal nitrogen stress responses for algal bioproduct production.

Abstract: Provided are surprisingly beneficial osmotic stress shock methods for facilitating disruption and/or extraction of microorganisms, comprising a synergistic combination of at least one hypotonic shock and at least two hypertonic shocks, wherein the last shock is a hypertonic shock. Preferred aspects of the invention relate to facilitating disruption of a broad spectrum of microorganisms (e.g., algae, bacteria, yeast, fungus, etc.). In particular aspects the microbial cells are subjected to: a hypertonic/hypotonic/hypertonic tertiary shock; a hypotonic/hypertonic/hypertonic tertiary shock; or a hypotonic/hypertonic/hypotonic/hypertonic quaternary shock. Particular aspects further comprise disrupting and/or extracting of the shocked microbial cells, and isolating a cellular constituent or bioproduct (e.g., biofuel, biocrude, bioenergy, biogas, biodiesel, bioethanol, biogasoline, pharmaceuticals, nutraceuticals, food, vitamins, feedstock, dyes, colorants, sulfur, fertilizer, bioplastic) therefrom.