Alkane monooxygenase diversity recovered from Central Asia sediments

Previous studies in our lab and elsewhere showed that different microbial gene groups are obtained from geographically distant sites. Alkane monooxygenases activate terminal carbon-carbon bonds in the first step of alkane degradation with the addition of an oxygen to the compound, resulting in an alcohol product. The aim of this study was to test the hypothesis that unique microbial populations and alkane monooxygenase (alkB and Cytochrome P450) genes can be recovered from geographically distinct sites, with varying degrees of anthropogenic impact. Sediment was collected from six river and stream sites with various levels of human impact located in Bishkek, Kyrgyzstan as well as Dushanbe and Khorog, Tajikistan, in Central Asia. The sites included rural and mountain streams, as well as rivers near or in cities. All sediments were enriched in media containing hexadecane as a carbon source and subcultured into fresh media with the alkane two times. DNA was extracted from each enrichment culture at various points throughout the enrichment for 16S rRNA and alkB clone library construction. The enrichment cultures were also analyzed by terminal restriction fragment length polymorphism (TRFLP) analysis of both 16S rRNA and alkB genes. The alkB and P450 genes, as well as 16S rRNA, were targeted with 454 pyrosequencing to obtain an estimate of microbial and alkane hydroxylase diversity at the sample locations and enrichments. The data show that distinct populations of alkB and P450 genes can be enriched from different locations and countries in Central Asia confirming that there is a wide diversity of alkane degrading genes in the environment.