Molecular analysis of meso- and thermophilic microbiota associated with anaerobic biowaste degradation.
BACKGROUND
Microbial anaerobic digestion (AD) is used as a waste treatment process to degrade complex organic compounds into methane. The archaeal and bacterial taxa involved in AD are well known, whereas composition of the fungal community in the process has been less studied. The present study aimed to reveal the composition of archaeal, bacterial and fungal communities in response to increasing organic loading in mesophilic and thermophilic AD processes by applying 454 amplicon sequencing technology. Furthermore, a DNA microarray method was evaluated in order to develop a tool for monitoring the microbiological status of AD.


RESULTS
The 454 sequencing showed that the diversity and number of bacterial taxa decreased with increasing organic load, while archaeal i.e. methanogenic taxa remained more constant. The number and diversity of fungal taxa increased during the process and varied less in composition with process temperature than bacterial and archaeal taxa, even though the fungal diversity increased with temperature as well. Evaluation of the microarray using AD sample DNA showed correlation of signal intensities with sequence read numbers of corresponding target groups. The sensitivity of the test was found to be about 1%.


CONCLUSIONS
The fungal community survives in anoxic conditions and grows with increasing organic loading, suggesting that Fungi may contribute to the digestion by metabolising organic nutrients for bacterial and methanogenic groups. The microarray proof of principle tests suggest that the method has the potential for semiquantitative detection of target microbial groups given that comprehensive sequence data is available for probe design.
Institute of Biotechnology, University of Helsinki, Viikinkaari 4, 00790, Helsinki, Finland. jarmo.ritari@helsinki.fi
Jarmo
J
Ritari
Kaisa
K
Koskinen
Jenni
J
Hultman
Jukka M
JM
Kurola
Maritta
M
Kymäläinen
Martin
M
Romantschuk
Lars
L
Paulin
Petri
P
Auvinen
D001105:Archaea / Q000145:classification*; D001419:Bacteria / Q000145:classification*; D058448:Biota; D005658:Fungi / Q000145:classification*; D017744:Medical Waste Disposal; D054892:Metagenome; D008697:Methane / Q000378:metabolism; D046228:Microarray Analysis; D009930:Organic Chemicals / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013696:Temperature
D017744:Medical Waste Disposal; D009930:Organic Chemicals; D008697:Methane