Abstract:In order to improve the flow properties of waxy crude oil, two strains were isolated from the oil contaminated soil near Liaohe Oilfield, which can degrade crude oil. The strains were identified as Cellulosi microbium sp. and Pseudomonas sp., and named 7# and 12# by 16S rRNA gene sequence analysis. The results showed that the compound bacteria could emulsify the liquid paraffin; when the volume ratio of compound bacteria was 1:1, the highest emulsification rate reached up to 77.5%; the optimal temperature was 35~40℃; the pH was 6~8, and the best growth of the compound bacteria was at the initial pH; the optimal inoculum volume ratio was 4%, the volume ratio was 2:1. After the crude oil was treated for 7 days with the compound bacteria at 37℃ and pH=7, the wax removal rate was 61.32% and the viscosity reduction rate reached up to 31.58%. Through microscope observation, wax crystals became smaller, further indicating that the strain could degrade the wax, which improved the flow properties of waxy crude oil.