The document describes integrating anaerobic digestion of sewage sludge with advanced biofuel production. Sewage sludge was treated with anaerobic digestion under two conditions: 1) low pH control and 2) chemical inhibition of methanogens. Both treatments resulted in accumulation of acetic acid. Acetic acid from digestion was then used as a carbon source for a fungus (Mortierella isabellina) and engineered Escherichia coli to produce fatty acids. The engineered E. coli strain had higher fatty acid yield and produced both medium and long chain fatty acids, while the fungus mainly produced long chain fatty acids. The study demonstrated a potential process to combine anaerobic digestion with microbial cultivation to simultaneously treat sewage