Ettlia oleoabundans growth and oil production on agricultural anaerobic waste effluents

The feasibility of growth and oil production by Ettlia oleoabundans fed with anaerobic digester effluents of three agriculture wastes from the Arkansas Delta, catfish processing waste, soybean field waste, and rice hulls, was studied. Compared to standard BBM medium, all three effluents were deficient in phosphate and nitrate, but rich in ammonia and urea. Best growth was on 2% (v/v) soy effluent, but scant oil was produced on any of the effluents. When the three effluents were mixed, growth did not substantially increase, but oil content increased up to sixfold, depending on age of the effluent. Similar to growth in BBM, the main fatty acids produced were palmitic, oleic, and linoleic. These results show that anaerobically digested agricultural wastes can potentially support both growth and high oil productivity in E. oleoabundans.