Significance and Impact of the Study: The resuscitation-promoting factor Rpf2 of Rhodococcus erythropolis was expressed and purified. The purified protein showed muralytic activity and protease activity. The purified protein promoted the R. erythropolis cell growth. The addition of the recombinant Rpf2 protein significantly increased petroleum degradation efficiencies of the indigenous micro-organisms of the contaminated soils. The recombinant protein also increased the cultivable petroleum-degrading bacteria diversities of the contaminated soils. The protein also promoted isolation effect of the oildegrading bacteria from the contaminated soils. The Rpf2 of R. erythropolis is an important bacterial growth stimulating factor.