Aerobic Biodegradation of Crude Oil Components by Acidophilic Mycobacteria

Аннотация

Biodegradation of crude oil components by strain AG_S10, an acidophilic member of the genus Mycobacterium, was studied under extremely acidic conditions (pH 2.5). The degree of degradation of the same hydrocarbons in different kinds of oil was found to be different. The direction of biodegradation was, however, the same: the share of n-alkanes in oxidized oil decreased, while the share of branched alkanes increased. At the same time, the degree of redistribution of methane hydrocarbons in degraded oil varied significantly for different oils, although no strict dependence on the type of oil was found. After 28 days of incubation at 30°C and pH 2.5, the degradation of n- and iso-alkanes was 99 and 44%, respectively for the light, low-viscosity oil of the Nizhnevartovsk deposit, 58 and 32%, respectively for the medium-density oil of the Moscow oil-procesing plant, and 80 and 16% and 99 and 69%, respectively for the heavy, viscous oils of the Cheremukhovskoe and Usinkoye oil fields. Moreover, after extended cultivation time strain AG_S10 completely utilized alkanes, as well as a significant part of the naphthene component of the aliphatic fraction. The studied strain was characterized by ability to oxidize a broad spectrum of methane hydrocarbons, including high-molecular C₁₇–C₃₀n-alkanes, in oils of different properties and composition. Apart from its scientific interest, farther investigation of biodegradation of high-paraffin oils and viscous oils with elevated paraffin content by strain AG_S10 may be useful in view of the technical issues associated with paraffin accumulation in the course of recovery and transportation of these oils.