Assessing effects of earthworm cast on methanotrophic community in a soil biocover by concurrent use of microarray and quantitative real-time PCR

Effects of earthworm cast (EC) on the methanotrophic community in a soil biocover were evaluated using microarray and quantitative real-time PCR (qRT-PCR). Soil was collected from a biocover with either soil alone or a mixture of soil and EC (3:1, w/w). The microarray results showed a more diverse methanotrophic community in the EC biocover than that in the soil biocover (p < 0.05). A principal component analysis result confirmed a substantial change in the methanotrophic community structure due to the added EC. Type I methanotrophs dominated both biocovers, with Methylobacter being most abundant. The qRT-PCR results showed that EC greatly increased the methanotrophic population levels (p<0.05) up to 100 fold. In conclusion, EC can increase the population density of methanotrophs as well as their diversity, resulting in a substantial shift in the community structure. The results confirmed the promising potential of EC as a bed material for enhancing the biocover performance. (C) 2011 Elsevier B.V. All rights reserved.