Taxonomic identification, phenol biodegradation and soil remediation of the strain Rhodococcus sacchari sp. nov. Z13.

Phenols are highly toxic chemicals that are extensively used in industry and produce large amounts of emissions. Notably, phenols released into the soil are highly persistent, causing long-term harm to human health and the environment. In this study, a gram-positive, aerobic, and rod-shaped bacterial strain, Z13, with efficient phenol degradation ability, was isolated from the soil of sugarcane fields. Based on the physiological properties and genomic features, strain Z13 is considered as a novel species of the genus Rhodococcus, for which the name Rhodococcus sacchari sp. nov. is proposed. The type strain is Z13 (= CCTCC AB 2022327 = JCM 35797). This strain can use phenol as its sole carbon source. Z13 was able to completely degrade 1200 mg/L phenol within 20 h; the maximum specific growth rate was μ = 0.93174 h, and the maximum specific degradation rate was q = 0.47405 h. Based on whole-genome sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, strain Z13 contains a series of phenol degradation genes, including dmpP, CatA, dmpB, pcaG, and pcaH, and can metabolize aromatic compounds. Moreover, the potential of strain Z13 for soil remediation was investigated by introducing Z13 into simulated phenol-contaminated soil, and the soil microbial diversity was analyzed. The results showed that 100% of the phenol in the soil was removed within 7.5 d. Furthermore, microbial diversity analysis revealed an increase in the relative species richness of Oceanobacillus, Chungangia, and Bacillus.