Premium
Ecophysiology of Defluviicoccus ‐related tetrad‐forming organisms in an anaerobic–aerobic activated sludge process
Author(s) -
Wong ManTak,
Liu WenTso
Publication year - 2007
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2007.01267.x
Subject(s) - biology , anaerobic exercise , alphaproteobacteria , activated sludge , microbiology and biotechnology , biochemistry , polyhydroxyalkanoates , acidogenesis , propionate , enhanced biological phosphorus removal , bioreactor , glycogen , food science , bacteria , wastewater , 16s ribosomal rna , botany , gene , anaerobic digestion , ecology , physiology , genetics , methane , engineering , waste management
Summary A group of uncultured tetrad‐forming organisms (TFOs) was enriched in an acetate‐fed anaerobic–aerobic sequencing membrane bioreactor showing deteriorated enhanced biological phosphorus removal capacity. Based on 16S rRNA gene clone library and fluorescence in situ hybridization (FISH) analyses, these TFOs were identified as novel members of the Defluviicoccus cluster in the Alphaproteobacteria , accounting for 90 ± 5% of the EUBmix FISH‐detectable bacterial cell area in the reactor biomass. Microautoradiography in combination with FISH and polyhydroxyalkanoate (PHA) staining revealed that these Defluviicoccus ‐related TFOs could take up and transform acetate, lactate, propionate and pyruvate, but not aspartic acid and glucose, into PHA under anaerobic conditions. In contrast, under continuous anaerobic–aerobic cultivation, Defluviicoccus vanus , the only cultured strain from the cluster, was able to take up glucose with concurrent glycogen consumption and PHA production under anaerobic conditions. Under subsequent aerobic conditions, the accumulated PHA was utilized and the biomass glycogen levels were restored. These findings not only re‐confirmed these Defluviicoccus ‐related TFOs as glycogen‐accumulating organisms, but also revealed unexpected levels of physiological, phylogenetic and morphological diversity among members of the Defluviicoccus cluster.