Enhanced fat degradation following the addition of a Pseudomonas species to a bioaugmentation product used in grease traps

The presence of fats, oils and greases(FOGs) in wastewater can lead to many problems including blockages. Investigation of a bioaugmentation product, consisting of Bacillus spp., to degrade butter(1%, W/V) and olive oil(1%, V/V) was performed in aerobic batch cultures for 13-day incubation. Gravimetric analysis of the remaining substrates showed slowly degradation of the oil after a 2-day lag, but no degradation of the butter. Addition of a Pseudomonas putida strain CP1 to the Bacillus spp. population promoted rapidly degradation of both fats after7 days of incubation. High fat accumulation revealed the potential use of the new bacterial mixture for production of added-value compounds. Lipase production only by the Bacillus spp.along with the analysis of the remaining lipids with thin layer chromatography and gas chromatography, suggested that the Bacillus spp. mainly only hydrolyzed the fat. The breakdown products were metabolized by the Pseudomonas putida CP1 performing preferential utilization of unsaturated fatty acids. Investigation of population dynamics using selective plating and a labeled Pseudomonas putida CP1::Tn7-gfp showed domination of the latter. The new mixture performed a successful cooperation with good potential for FOG treatment and an aggregative response desirable to fat degradation in grease traps.