Halet Dirk, Boon Nico, Verstraete Willy
Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium.
J Biosci Bioeng. 2006 Apr;101(4):297-302. doi: 10.1263/jbb.101.297.
In this study, we describe the effects of composting on the diversity, abundance and activity of the methanotrophic community present in the compost. Composting was allowed to proceed for 10 weeks in an in-vessel reactor. Self-heating capacity (Rottegrad) indicated that compost maturity was reached after 4 weeks. After 6 weeks, a second thermophilic phase was induced by manually increasing temperature to investigate whether or not the methanotrophs shifted back to the thermophilic population. Polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) with primers specific for type I methanotrophs of 16S rDNA and 16S rRNA were used to characterize the composition of the microbial community. Cluster and diversity analyses of RNA DGGE patterns were more sensitive than those of DNA DGGE patterns, and revealed that mesophilic and thermophilic methanotrophic communities could be differentiated. Moreover, it was seen that the diversity of the community was low during the thermophilic phase and increased during the final maturation phase. Real-time PCR analysis was also performed on the DNA and RNA extracts and showed no changes in the abundance of type I methanotrophs during the composting process (10(9) DNA copies/g compost). However, RNA-related activity did change, with the lowest activity (10(7) cDNA copies/g compost) observed during the thermophilic phase, subsequently increasing to its maximum value (10(9) cDNA copies/g compost), and finally decreasing during the maturation phase. This study confirmed the population dynamics, as seen for general groups such as bacteria and fungi during composting, for a very specific and sensitive group of bacteria, it is the type I methanotrophs.
在本研究中，我们描述了堆肥对堆肥中存在的甲烷氧化菌群落的多样性、丰度和活性的影响。在一个内置式反应器中进行了10周的堆肥过程。自热能力（Rottegrad）表明4周后堆肥达到成熟。6周后，通过手动升高温度诱导第二个嗜热阶段，以研究甲烷氧化菌是否会转变回嗜热菌群。使用针对16S rDNA和16S rRNA的I型甲烷氧化菌的特异性引物进行聚合酶链反应（PCR）-变性梯度凝胶电泳（DGGE），以表征微生物群落的组成。RNA DGGE图谱的聚类和多样性分析比DNA DGGE图谱更敏感，并且揭示了中温型和嗜热型甲烷氧化菌群落可以区分。此外，可以看出，在嗜热阶段群落的多样性较低，而在最终成熟阶段有所增加。还对DNA和RNA提取物进行了实时PCR分析，结果表明在堆肥过程中I型甲烷氧化菌的丰度没有变化（10⁹个DNA拷贝/克堆肥）。然而，与RNA相关的活性确实发生了变化，在嗜热阶段观察到最低活性（10⁷个cDNA拷贝/克堆肥），随后增加到其最大值（10⁹个cDNA拷贝/克堆肥），并最终在成熟阶段下降。本研究证实了堆肥过程中像细菌和真菌等一般菌群所呈现的种群动态，对于一类非常特殊且敏感的细菌，即I型甲烷氧化菌也是如此。
