BACKGROUND: Municipal wastewater could be a potential growth medium that has not been considered for cultivating oleaginous microorganisms. This study is designed to determine if a consortium of oleaginous microorganism can successfully compete for carbon and other nutrients with the indigenous microorganisms contained in primary effluent wastewater. RESULTS: The oleaginous consortium inoculated with indigenous microorganisms reached stationary phase within 24 h, reaching a maximum cell concentration of 0.58 g L-1. Water quality post-oleaginous consortium growth reached a maximum chemical oxygen demand (COD) reduction of approximately 81%, supporting the consumption of the glucose within 8 h. The oleaginous consortium increased the amount of oil produced per gram by 13% compared with indigenous microorganisms in raw wastewater. Quantitative polymerase chain reaction (qPCR) results show a substantial population increase in bacteria within the first 24 h when the consortium is inoculated into raw wastewater. CONCLUSION: This result, along with the fatty acid methyl esters (FAMEs) results, suggests that conditions tested were not sufficient for the oleaginous consortium to compete with the indigenous microorganisms. (C) 2010 Society of Chemical Industry