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矿井本源Methylobacter与Methylophilus属菌代谢甲烷特性

Methane metabolism characteristics of indigenous Methylobacter and Methylophilus genera in mines

  • 摘要: 煤矿甲烷排放不仅导致温室效应,更易积聚造成瓦斯爆炸等灾害事故,严重威胁矿井人员生命安全。为此,针对采空区甲烷蓄积及污染问题,从煤矿环境提取本源微生物,采用唯一碳源法进行富集驯化及分离纯化,得到2株甲烷氧化菌Methylobacter tundripaludum SV96T(T)与Methylophilus sp. D22(S)。使用单因素试验法进行培养条件优化,探究菌株的环境适应性及反应动力学。结果表明:两菌株均可利用蛋白胨、甲醇进行生长,可以作为实现扩大培养的辅助碳源;揭示了两菌株的环境适应性,即菌株S在试验多种条件下展现出显著环境适应性,菌株T对环境变化较敏感;确定两菌株的最佳培养温度均为35 ℃,菌株T:pH 7-接种量10%,菌株S:pH 8-接种量5%,最适培养条件下,甲烷消耗率分别达到(88.83±4.8)%、(83.21±5.1)%;动力学研究表明,菌株T、S生长整体符合Logistic增长模型,对数期比生长速率bmax分别为0.029 9 h−1、0.035 3 h−1,生长−甲烷消耗呈线性正相关,并从传质角度提出优化建议与应用策略;甲烷氧化过程中,CH4消耗与CO2生成的摩尔速率之比接近2∶1,符合甲烷氧化菌将碳源分配于氧化产能与生长的代谢模式,为包括煤矿甲烷治理的甲烷减排工程提供了优化方案,在模拟采空区环境代谢CH4试验中,66 h内T、S菌液均将CH4体积分数代谢至0.1%以下,拟合发现两者的代谢过程遵循Logistic衰减规律。试验表明,菌株S具有更强的环境适应性及应急处理能力,而菌株T需在稳定工况中先定殖存活,以实现高效代谢。研究结果为采空区甲烷的微生物治理技术提供菌种资源及理论基础。

     

    Abstract: Coal mine methane tends to accumulate, leading to gas explosions and other disasters and posing a serious threat to the safety of mine personnel. To address this problem, two methane-oxidizing bacteria (MOB) are isolated from the coal mine environment through enrichment culture with methane as the sole carbon source,and are identified as Methylobacter tundripaludum SV96T (strain T) and Methylophilus sp. D22 (strain S). The culture conditions of the two strains are optimized by the one-factor-at-a-time method, and their environmental adaptability and reaction kinetics were investigated. The results showed that both strains canutilize peptone and methanol for growth, and these substances can serve as auxiliary carbon sources for scale-up cultivation. Meanwhile, the two strains differ in environmental adaptability: strain S exhibits strong environmental adaptability under various experimental conditions, whereas Strain T is relatively sensitive to environmental changes. The optimal culture temperature for both strains is 35 ℃. For strain T, the optimal pH and inoculation amount are 7 and 10%, respectively, and 8 and 5% for strain S. Under the optimal culture conditions, the methane consumption rates of strains T and S reach (88.83±4.8)% and (83.21±5.1)%, respectively. Kinetic analysis shows that the overall growth of strains T and S conformed to the Logistic growth model, with maximum specific growth rates bmax in the logarithmic phase of 0.029 9 h−1 and 0.035 3 h−1, respectively. A linear positive correlation is observed between growth and methane consumption, and optimization suggestions and application strategies proposed from the perspective of mass transfer. The CH4 oxidation process exhibits a conversion characteristic in which the molar consumption rate of CH4 is approximately twice the molar production rate of CO2, which is consistent with the metabolic pattern of methanotrophs partitioning carbon between oxidative energy production and growth. The above results provide an optimization scheme for methane emission reduction projects, including coal mine methane control. In the experiment simulating the goaf environment, both strainsT and S reduce the CH4 volume fraction to below 0.1% within 66 h, and fitting reveals that their metabolic processes follow the Logistic decay kinetics. The experiment shows that strain S exhibitsstronger environmental adaptability and a stronger rapid response capability, whereas strain T requires prior colonization and survival under stable operating conditions before achieving efficient metabolism. The results provide strain resources and a theoretical basis for the microbial treatment technology of CH4 in goafs.

     

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