The micro-organism Vitreoscilla filiformis (Vf) was cultivated on a defined and sterile medium, expanded and isolated to constitute a biomass called "pure extract of thermal plankton". The term plankton describes the zooplankton (chemiotrope microorganisms) in contrast to the phytoplankton (phototrope microorganisms). At the end of culturing, the biomass is concentrated by stabilized centrifugation and autoclaved.