Isolation and degradation characterization of C24MT1, a highly effective long-chain alkane-degrading bacterium

Abstract:

[Background] Petroleum is known as liquid gold. While creating a great social value, the utilization of petroleum for industrial production causes serious pollution to the environment. Microbial remediation is one of the effective approaches to control oil pollution, which has the advantages of low cost, high efficiency, and no secondary pollution. [Objective] To isolate and study the degradation characteristics and microbial remediation potential of highly efficient n-tetracosane-degrading strain from the oil-contaminated soil. [Methods] The strain was identified by morphological observation and 16S rRNA gene sequencing. Gas chromatography was employed to examine the n-tetracosane degradation effect of the strain. Further, we employed gas chromatography-mass spectrometry (GC-MS) to identify the degradation intermediates for predicting the potential metabolic pathway. [Results] Strain C24MT1 was identified as Acinetobacter sp., which was highly capable of degrading n-tetracosane. The optimum degradation conditions of the strain were 30 °C, pH 9.0, and salinity of 2 g/L, under which the degradation rate of 9 g/L n-tetracosane was 86.63%. The strain grew well (OD₆₀₀=0.39) in strong alkaline environment (pH 11) and maintained high alkane degradation rate (75.38%), demonstrating strong tolerance to extreme environment. According to the degradation intermediates, we predicted that the metabolic pathways of n-tetracosane in the strain might include terminal oxidation and subterminal oxidation. [Conclusion] Acinetobacter sp. C24MT1 had excellent environmental adaptability and alkane-degrading ability, demonstrating great application prospects in the development of microbial inoculants and the remediation of petroleum-contaminated soil. This study provides excellent bacterial resources for the remediation of soil contaminated by high-concentration petroleum in saline-alkali areas and enriches the bacterial resource for the biodegradation of petroleum hydrocarbons.

Key words:petroleum hydrocarbons;biodegradation;Acinetobacter;degradation characteristics;metabolic pathways