Evidence of compositional differences between the extracellular and intracellular DNA of a granular sludge biofilm
Article first published online: 31 MAY 2011
© 2011 The Authors. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology
Letters in Applied Microbiology
Volume 53, Issue 1, pages 1–7, July 2011
How to Cite
Cheng, M., Cook, A.E., Fukushima, T. and Bond, P.L. (2011), Evidence of compositional differences between the extracellular and intracellular DNA of a granular sludge biofilm. Letters in Applied Microbiology, 53: 1–7. doi: 10.1111/j.1472-765X.2011.03074.x
- Issue published online: 10 JUN 2011
- Article first published online: 31 MAY 2011
- Accepted manuscript online: 5 MAY 2011 10:14AM EST
- 2010/2167: received 30 November 2010, revised 13 March 2011 and accepted 27 March 2011
- aerobic granular sludge;
- cation exchange resin;
- extracellular polymeric substances extraction;
- extracellular DNA
Aims: Extracellular polymeric substances (EPS) are an important component of microbial biofilms, and it is becoming increasingly apparent that extracellular DNA (eDNA) has a functional role in EPS. This study characterizes the eDNA extracted from the novel activated sludge biofilm process of aerobic granules.
Methods and Results: Exposing the sludge to cation exchange resin (CER) was used for the extraction of eDNA and intracellular DNA (iDNA) from aerobic granules. This was optimized for eDNA yield while causing minimal cell lysis. We then compared the DNA composition of these extractions using randomly amplified polymorphic DNA (RAPD) fingerprinting and PCR-based denaturing gradient-gel electrophoresis (DGGE). Upon the analysis of the genomic DNA and the 16S rRNA genes, differences were detected between the sludge biofilm eDNA and iDNA.
Conclusions: Different bacteria within the biofilm disproportionally release DNA into the EPS matrix of the biofilm.
Significance and Impact of the Study: The findings further the idea that eDNA has a functional role in the biofilm state, which is an important conceptual information for industrial application of biofilms.