S41: Production of omega-3 polyunsaturated fatty acids from biodiesel-waste glycerol by microalgal and fungal fermentation

Glycerol is the major byproduct in the biodiesel industry. Because it is prohibitively expensive to purify the crude glycerol for use in industry, biodiesel producers must find alternate methods for disposal. The objective of this work is to develop an algal and a fungal culture process using biodiesel derived crude glycerol as a carbon source for producing high levels of omega-3 polyunsaturated fatty acids, DHA and EPA, with medically established therapeutic capabilities against several diseases. The microalga Schizochytrium limacinum was used as the DHA producer; while the fungus Pythium irregulare was used as EPA producer. The glycerol samples contained methanol, soaps, and various elements including calcium, phosphorus, potassium, silicon, sodium, and zinc.  The results show that crude glycerol was a suitable carbon source for fermentation of these two species.  The crude glycerol-derived biomass had a high level of DHA/EPA and a nutritional profile similar to commercial algal biomass, suggesting a great potential for using crude-glycerol derived algae/fungi in omega-3 fortified food or feed.