outlined herein but rather that concentrations times and other specific details may be modified through routine experimentation in some cases well known methods or components have not been included in the description embodiments herein represent methods and compositions for harvesting and using harvest suspension culture yields in some embodiments the cultures can be algae bacteria fungi or yeast cultures products contemplated herein for production from the algal yields can include but are not limited to biofuels protein vitamins carbohydrates and or amino acids in certain embodiments particles or heavy materials may be used as coagulants or concentrators of suspension cultures or wastewaters e g for removal of particulates or microorganisms for example in some embodiments microorganisms can associate with particles or heavy materials by adjusting the condition of the culture media in order to harvest the microorganisms previously it was demonstrated that adsorbed algae particles can be removed from water by a magnetic field algae were removed by passing through a high gradient magnetic filtration hgmf in this study about 90 of algae were removed at 500 1 200 mg l of magnetite as magnetic seeds in laboratory batch experiments one of the problems of this method was that removal of the algae required a large concentration of iron ions as a primary coagulant and iron coagulants tended to modify the algae surfaces reducing production of the algae and the coagulants could not be recycled for reuse making it an expensive process in some embodiments algae surfaces can be modified prior to adsorption using methods disclosed herein in certain embodiments algal suspension cultures can be changed to hydrophobic cultures prior to harvesting in accordance with these embodiments magnetite particles often do not meet such a hydrophobic.