Deep Desulfurization of Diesel Oil and Crude Oils by a Newly Isolated Rhodococcus erythropolis Strain

Abstract

The soil-isolated strain XP was identified as Rhodococcus erythropolis. R. erythropolis XP could efficiently desulfurize benzonaphthothiophene, a complicated model sulfur compound that exists in crude oil. The desulfurization product of benzonaphthothiophene was identified as ␣-hydroxy-␤-phenyl-naphthalene. Resting cells could desulfurize diesel oil (total organic sulfur, 259 ppm) after hydrodesulfurization. The sulfur content of diesel oil was reduced by 94.5% by using the resting cell biocatalyst for 24 h at 30°C. Biodesulfurization of crude oils was also investigated. After 72 h of treatment at 30°C, 62.3% of the total sulfur content in Fushun crude oil (initial total sulfur content, 3,210 ppm) and 47.2% of that in Sudanese crude oil (initial total sulfur, 1,237 ppm) were removed. Gas chromatography with pulsed-flame photometric detector analysis was used to evaluate the effect of R. erythropolis XP treatment on the sulfur content in Fushun crude oil, and it was shown that most organic sulfur compounds were eliminated after biodesulfurization.

Genome Sequence of Rhodococcus erythropolis XP, a Biodesulfurizing Bacterium with Industrial Potential

“…Moreover, it is considered that Rhodococcus is a natural reservoir of new biosurfactants that are highly efficient and ecologically friendly and have a wide range of applications in oil, food, and pharmaceutical industries and in pollutant removal (7). R. erythropolis XP is a strain isolated from soils and has been proved efficient in deep desulfurization of petroleum oils, including gasoline, diesel, and crude oil, through the 4S pathway (10,12). Strain XP was also successfully used as a host for developing a recombinant biocatalyst for biodetoxification of S/N/O pollutants (11).…”

Selective Biodegradation of S and N Heterocycles by a Recombinant Rhodococcus erythropolis Strain Containing Carbazole Dioxygenase

“…In general, the lower the number of alkyl carbons on the CA ring, the more susceptible the compound was to biodegradation. The distribution of sulfur-containing compounds in crude oil was determined by GC with a pulsed-flame photometric detector (24). Sulfur compounds with retention times longer than that of DBT were desulfurized, and almost all of the highly alkylated sulfur compounds present at a detectable level were also removed (Fig.…”

“…In this study, a CA dioxygenase gene was introduced into the excellent DBT degrader Rhodococcus erythropolis XP (24), which could desulfurize DBT via a 4S pathway. The resultant recombinant was designated SN8.…”

The optimization of desulfurization conditions by response surface methodology

“…Bio desulfurization is a method to selectively convert the sulfur content of oil into water soluble sulfur compounds by microbial enzymes, and then through the oil and water separation method, the purpose of oil desulfurization will be achieved. Compared with catalytic desulfurization, bio desulfurization has many advantages, such as less investment, lower operating cost, cleaner and easier removal of thiophene compounds and so on, but it also has the following shortcomings at the same time, for example, flexibility is low, the process is not easy to control, and more stringent requirements are needed, due to the growth of microorganisms requires a certain condition [9][10][11][12]. It is a very important thing to create a good growth condition for the microorganism to improve the desulfurization efficiency.…”