Method of microalgal biomass processing for high-value chemicals production, the resulting composition of butyrogenic algal slowly fermenting dietary fiber, and a way to improve colon health using a slowly fermenting butyrogenic algal dietary fiber

A method to extract and isolate compounds from an algal biomass consisting of the steps:

• physically treating, optionally preceded by a growth pre-treatment of the algal biomass, the algal biomass by micro fluidization or ultra-sonication with a frequency greater than 20 KHz using a probe-type sonication or bath sonication, optionally in combination with extrusion using an extruder or with addition of a solvent, wherein the solvent is hexane, followed by
• centrifugation, wherein centrifugation of the physically treated biomass was performed at a speed of about 500 rpm to about 15000 rpm, followed by
• separating lipids and other oils at the top layer, the water soluble chemicals at the middle layer and the pellet at the bottom layer,
• hydrothermally treating the pellet by heating at alkaline pH, optionally in combination with pressure greater than 0.5 bar, while stirring, followed by
• centrifugation of the hydrothermally treated pellet at 2500 rpm for 10 minutes or 4000 rpm for 15 min,
• separating the supernatant from the resulting residue of the hydrothermally treated pellet, precipitating water-soluble polysaccharides from the supernatant, wherein the precipitated polysaccharides were washed and pH adjusted to about 7, and dried, and
• extracting carotenoids from the resulting residue using solvent, optionally including ultra-sonication or drying.