The invention relates to methods for harvesting macromolecules such as lipids and proteins by culturing in growth medium a photo synthetic cyanobacteria that secretes vesicles into the growth medium, and separating the secreted vesicles from the cyanobacteria and/or from the growth medium.
 This invention was made with Government support under Grant No. OCE0425602 awarded by the National Science Foundation, and under Grant No. DE-FG02-08ER64516 awarded by the U.S. Department of Energy. The Government has certain rights in this invention.