I don't know what you mean by "extraction" (algae-water harvest or oil-algae extraction?) But I worked in aquaculture and we harvested first a centrifuge (westfalia) then breaking the cell membranes by ultrasound .... Maybe the ultrasound method is transferable?
Have you looked in this document: https://www.econologie.com/file/biocarbu ... S_NREL.pdf
Otherwise, it would also be necessary to look on the side of patents (oil companies for the most part ...).