Metagenomic analysis of the complex microbial consortium associated with cultures of the oil-rich alga Botryococcus braunii
Wiley Open Access
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.
Microalgae are widely viewed as a promising and sustainable source of renewable chemicals and biofuels. Botryococcus braunii synthesizes and secretes significant amounts of long-chain (C30-C40) hydrocarbons that can be subsequently converted into gasoline, diesel, and aviation fuel. B. braunii cultures are not axenic and the effects of co-cultured microorganisms on B. braunii growth and hydrocarbon yield are important, but sometimes contradictory. To understand the composition of the B. braunii microbial consortium, we used high throughput Illumina sequencing of metagenomic DNA to profile the microbiota within a well established, stable B. braunii culture and characterized the demographic changes in the microcosm following modification to the culture conditions. DNA sequences attributed to B. braunii were present in equal quantities in all treatments, whereas sequences assigned to the associated microbial community were dramatically altered. Bacterial species least affected by treatments, and more robustly associated with the algal cells, included members of Rhizobiales, comprising Bradyrhizobium and Methylobacterium, and representatives of Dyadobacter, Achromobacter and Asticcacaulis. The presence of bacterial species identified by metagenomics was confirmed by additional 16S rDNA analysis of bacterial isolates. Our study demonstrates the advantages of high throughput sequencing and robust metagenomic analyses to define microcosms and further our understanding of microbial ecology.
Shell Research Limited; Biotechnology and Biological Sciences Research Council, Grant/ Award Number: BB/K003240/2 and BB/ K003240/1; Medical Research Council Clinical Infrastructure award, Grant/Award Number: MR/M008924/1; Wellcome Trust Institutional Strategic Support Fund, Grant/Award Number: WT097835MF; Wellcome Trust Multi User Equipment Award, Grant/Award Number: WT101650MA
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