Selection of fat-degrading microorganisms for the treatment of lipid-contaminated environment

Abstract

To develop effective microbial agents applicable to complex technology for grease wastes utilization, a total of 124 microorganisms were screened for their ability to degrade lipidic compounds. The screening yielded five strains (UP2, F2, E13, Kl1 and N3) showing lipolytic activity and rapidly degrading sunflower and olive oil, tallow and lard. Among them, strains E13 and N3 were found to have the highest lipase activity and the more intensive rates of the degradation of saturated (palmitic and stearic) and unsaturated (oleic and linoleic) fatty acids and triglycerides containing these fatty acids. The strains were obtained from the culture collection of JSC “Biocentras” and identified as Enterobacter aerogenes E13 and Arthrobacter sp. N3. When a mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 was grown in a mineral medium containing 0.5% of sunflower oil, the hydrolysis products were diglycerides, monoglycerides and free fatty acids. Moreover, the mixed culture was consuming these hydrolysis products during cultivation at 30 °C. Investigation of lard biodegradation in black soil showed that a mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 degraded lard about 7 times more intensively than indigenous soil microorganisms (after six weeks of degradation in black soil, the concentration of lard was reduced by 87.5 and 8.0%, respectively). Therefore, the mixed culture of strains E. aerogenes E13 and Arthrobacter sp. N3 may be used for an effective grease waste reduction in a complex cleaning technology. Keywords: fat degradation, Enterobacter, Arthrobacter, lipase