Change of bacterial community in oil-polluted soil after enrichment cultivation with low-molecular-weight polyethylene

- The amount of 16S rRNA decreased while the alkB/16S rRNA ratio increased with increase of LMWPE enrichment cultivation.
- Abundance of genera Curtobacterium, Gordonia and Rhodococcus increased over the course of enrichment cultivation.
- The LMWPE biodegradability was higher in the sterilized compost inoculated with the LMWPE enrichment culture experienced soil.

Enrichment cultivation was performed after a seashore soil polluted by crude oil was inoculated into a basal medium with low-molecular-weight polyethylene (LMWPE) powder as the sole carbon source. From the whole DNAs, alkane monooxygenase gene (alkB), which has been reported to participate in the degradation of polyethylene, was measured with quantitative real-time PCR to monitor the abundance of polyethylene degrading bacteria in the culture. The change in the ratio of alkB/16S rRNA in the culture broth as a function of enrichment cultivation time was measured and used as an index for the ratio of microbes with alkB to those in the entire bacterial community in the culture broth. Through 16S rRNA sequence analysis, the bacterial community was analyzed at the genus level. With this technique, the changes in the community of soil microbes and their diversity as a function of enrichment cultivation time were examined. In addition, improvement in the LMWPE degradation ability of the bacterial community due to LMWPE enrichment cultivation was analyzed through biodegradability testing under controlled compost conditions.