Evidence of species succession during chlorobenzene biodegradation

Abstract

We have previously reported the disappearance of a specific strain degrading chlorobenzene from a functionally stable bioreactor. In the present work, we investigated this species succession and isolated a new dominant strain, identified as Pandoraea pnomenusa sp. strain MCB032. A specific 16S rRNA-targeted oligonucleotide probe was designed and validated to identify strain MCB032 using fluorescence in situ hybridisation (FISH). The results confirmed the presence of strain MCB032 in samples collected over time, and showed that it was primarily located within the biofilm. Denaturing gradient gel electrophoresis (DGGE) provided evidence that the species succession occurred early in the operating period. The application of these biomolecular tools highlighted the remarkable stability of this new strain during the 15 months of reactor operation. The succession was attributed to the competitive kinetic behaviour of strain MCB032, which exhibited faster growth (micro(max) = 0.34 h(-1)) and higher substrate affinity (K(s) = 0.35 mg L(-1)) than strain JS150. Finally, this study contributed to the characterisation of the recently established Pandoraea genus, an emerging group in the biodegradation field.

Model for a solid–liquid stirred tank two-phase partitioning bioscrubber for the treatment of BTEX

“…One of the important observations is that the maximum specific growth rates that were estimated are an order of magnitude lower than the original values. This may be possibly attributed to a change in the population distribution and kinetics of the microbial consortium from the time these kinetic values were initially determined [25] until the experimental step changes were performed [5], as it is known that microbial consortia populations can change during the length of time of biodegradation experiments [34]. Also, biological activity from short shake flask experiments may not reflect biological activity during lengthy bioreactor runs.…”

Influence of key physicochemical and hydrodynamic specifications of three packing materials on both performance and bacterial community structure of gas‐biofilters

“…Moreover, it is well known that operating conditions and contaminant loading are more important factors than the inoculum structure in developing the community within the biofilters, when the inoculation and/or the packing material bring enough diversity to allow the emergence of adapted species. Then, in the present case, biofilter communities seem to be mostly influenced by the characteristics of the packing material even if the inoculation seems to favour the emergence of fitted species, the enrichment and dominance of a specific population being due to its competitive advantages in terms of growth and substrate affinity, as highlighted by kinetic studies …”

ERIC-PCR-based strain-specific detection of phenol-degrading bacteria in activated sludge of wastewater treatment systems

“…Many methods have been developed to identify the presence of certain bacteria in microbial communities (Ben‐Dov et al. 2007; Baptista et al. 2008) and to demonstrate the subgroup composition of specific populations (de Azeredo et al.…”