NOVELTY - Producing microbial intracellular products, involves growing microorganisms in a bioreactor and subjecting the grown microorganisms to fed-batch culture using volatile fatty acids as substrates to produce microbial intracellular products.    USE - For producing microbial intracellular products selected from intracellular proteins, intracellular organic polymers, and microbial lipids (claimed) (used as a raw material for biodiesel).    ADVANTAGE - The method industrially produces microbial intracellular products in a cost-effective manner and utilizes sugars such as glucose; utilizes inexpensive volatile fatty acids as substrates (carbon sources) while minimizing microbial growth inhibition resulting from the volatile fatty acids; maximizes the production of microbial intracellular products; and maximizes the productivity of a microbial reactor using a single bioreactor or a multi-stage continuous high-cell-density reactor system. The microbial intracellular products can be produced in a cost-effective manner using inexpensive volatile fatty acids as carbon sources instead of glucose. Among the produced microbial intracellular products, microbial lipids can be used as a raw material for biodiesel, and thus can also contribute to increasing the cost-effectiveness of biodiesel. The microorganisms were cultured in a medium containing little or no volatile fatty acids. As a result, the production of microbial lipid among microbial intracellular products is increased.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is inluded for producing microbial intracellular products from volatile fatty acids in a multi-stage continuous high-cell-density bioreactor system, involving: (a) culturing microorganisms in a bioreactor for microbial growth, thereby growing the microorganisms; (b) culturing the grown microorganisms of step (a) in a bioreactor including a medium containing volatile fatty acids, thereby producing microbial intracellular products; and (c) recovering the microbial intracellular products from the culture medium of the bioreactor for production of microbial intracellular products.