一株耐碱高效长链烷烃降解菌C24MT1的筛选及其降解特性

【背景】石油被称为“液体黄金”，人类的工业生产活动在利用其创造巨大社会价值的同时，也对自然环境造成了严重的污染。微生物修复技术是现阶段治理石油类污染有效的手段之一，具有经济、高效、无二次污染等优点。【目的】从受石油污染的土壤中分离高效降解长链烷烃正二十四烷的菌株，探究其降解特性及在微生物修复中的应用前景。【方法】通过形态学及16S rRNA基因测序进行菌株鉴定，采用气相色谱法检测菌株对正二十四烷的降解效果，并结合气相色谱-质谱(gas chromatography-mass spectrometer, GC-MS)分析降解中间产物以推测其潜在代谢途径。【结果】筛选到一株可高效降解正二十四烷的菌株C24MT1，经鉴定为不动杆菌属(Acinetobacter)。该菌株最适降解条件为30 °C、pH 9.0、盐度2 g/L，该条件下生长7 d对9 g/L正二十四烷的降解率高达86.63%；与此同时，菌株在强碱性环境(pH 11.0)中生长良好(OD₆₀₀为0.39)并保持较高烷烃降解率(75.38%)，对极端环境具备较强的耐受能力；对降解中间产物进行分析，推断菌株代谢长链烷烃正二十四烷的途径可能包括末端氧化及次末端氧化。【结论】不动杆菌C24MT1具有良好的环境适应能力及烷烃降解能力，在后续微生物菌剂开发和石油类污染土壤的环境修复领域具有巨大的应用前景。本研究可为盐碱地区高浓度石油类污染土壤的修复提供优良菌种，并进一步丰富石油烃类生物降解的菌种资源库。

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

[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.