NOVELTY - Simultaneously enhancing the production of both methane and volatile fatty acids in an anaerobic digestion bioreactor comprises providing a stream of organic feedstock; providing anaerobic digester bioreactors, each of the anaerobic digester bioreactors connected in series; and step-feeding predetermined percentages of the stream of organic feedstock to two or more of the anaerobic digester bioreactors connected in series.    USE - The method is used for simultaneously enhancing the production of both methane and volatile fatty acids in an anaerobic digestion bioreactor. The system is used for converting volatile fatty acids to lipids (all claimed).    ADVANTAGE - Methods and systems include anaerobic bioreactors using a step feed pattern to simultaneously increase the yield of methane and volatile fatty acid production. A step feed pattern introduces the feedstock to the bioreactor during different stages of digestion, rather than all the material at once in the beginning. This step feed pattern allows better mixing of the feedstock with the microbes, increasing the yield and kinetics of both methane and volatile fatty acid production in computer simulations. The step feed design allows the bioreactor to consist of multiple smaller tanks that may be better suited for environments with less available space. Methods and systems are adaptable for simultaneously enhancing the production of methane and volatile fatty acids from virtually any organic feedstock and can also be applied to waste streams from existing domestic (including, but not limited to high-rise multi-dwelling communities, new residential or commercial developments, hospital or educational complexes). Methods and systems are a novel way to produce lipids using substrates (volatile fatty acids), which are widely produced during anaerobic digestion of organic wastes and substrates. Using methods and systems according to the disclosed subject, it is possible to convert the volatile fatty acids into lipids. Lipids are an attractive product, since they can be converted directly to biodiesel, thus it is possible to convert just any organic compound (through first anaerobic conversion to volatile fatty acids) to lipids. This system is also superior to current lipid pipelines for biodiesel, including algae, since the yeasts and fungi can convert volatile fatty acids to lipids, which algae cannot. Additionally, this technology avoids the use of food commodities for the production of biodiesel, including from jatropha or cooking oils. Instead, it provides a flexible platform for integrating waste treatment into biofuels (biodiesel) production.    DETAILED DESCRIPTION - Simultaneously enhancing the production of both methane and volatile fatty acids in an anaerobic digestion bioreactor comprises providing a stream of organic feedstock; providing anaerobic digester bioreactors, each of the anaerobic digester bioreactors connected in series; step-feeding predetermined percentages of the stream of organic feedstock to two or more of the anaerobic digester bioreactors connected in series; feeding effluent from each of the anaerobic digester bioreactors to a subsequent one of the anaerobic digester bioreactors in the connected series of anaerobic digester bioreactors; and anaerobically digesting the stream of organic feedstock and the effluent from each of the anaerobic digester bioreactors to develop a final effluent stream including methane and volatile fatty acids. An INDEPENDENT CLAIM is a system for converting volatile fatty acids to lipids, comprising: a supply stream of organic feedstock; a feedstock treatment module for producing both methane and volatile fatty acids from the supply stream of organic feedstock, the feedstock treatment module including anaerobic digester bioreactors fluidly connected in series and fluidly joined with the supply stream of organic feedstock and adjustable valves for step-feeding predetermined percentages of the supply stream of organic feedstock to two or more of the anaerobic digester bioreactors; and an aerobic bioreactor for converting the volatile fatty acids produced by the anaerobic digester bioreactors in the feedstock treatment module to lipids.