BACKGROUND: Fermentative production of 1-butanol yields dilute aqueous solutions. Recovery of the butanol from these solutions is most commonly performed by energy-intensive distillation. This work investigated the liquid-liquid (L-L) phase behavior of mixtures of butanol and water to explore the potential of using L-L phase separation as a recovery possibility for 1-butanol. The phase behavior is preferably influenced by compounds already present in the fermentation, such as carbohydrates and salts.
Microbial
presence and regrowth in drinking water distribution
systems (DWDSs) is routinely monitored to assess the biological stability
of drinking water without a residual disinfectant, but the conventional
microbiological culture methods currently used target only a very
small fraction of the complete DWDS microbiome. Here, we sequenced
16S rRNA gene amplicons to elucidate the attached and suspended prokaryotic
community dynamics within three nonchlorinated DWDSs with variable
regrowth conditions distributing similarly treated surface water from
the same source. One rural location, with less regrowth related issues,
differed most strikingly from the other two urban locations by the
exclusive presence of Pseudonocardia (Actinobacteria) in the biofilm and
the absence of Limnobacter (Betaproteobacteriales) in the water and loose deposits
during summer. There was a dominant seasonal effect on the drinking
water microbiomes at all three locations. For one urban location,
it was established that the most significant changes in the microbial
community composition on a spatial scale occurred shortly after freshly
treated water entered the DWDS. However, summerly regrowth of Limnobacter, one of the dominant genera in the distributed
drinking water, already occurred in the clean water reservoir at the
treatment plant before further distribution. The highlighted bacterial
lineages within these highly diverse DWDS communities might be important
new indicators for undesirable regrowth conditions affecting the final
drinking water quality.
Bathers release bacteria in swimming pool water, but little is known about the fate of these bacteria and potential risks they might cause. Therefore, shower water was characterized and subjected to chlorination to identify the more chlorine-resistant bacteria that might survive in a chlorinated swimming pool and therefore could form a potential health risk. The total community before and after chlorination (1 mg Cl L for 30 s) was characterized. More than 99% of the bacteria in the shower water were Gram-negative. The dominant bacterial families with a relative abundance of ≥10% of the total (non-chlorinated and chlorinated) communities were Flavobacteriaceae (24-21%), Xanthomonadaceae (23-24%), Moraxellaceae (12-11%) and Pseudomonadaceae (10-22%). The relative abundance of Pseudomonadaceae increased after chlorination and increased even more with longer contact times at 1 mg ClL. Therefore, Pseudomonadaceae were suggested to be relatively more chlorine resistant than the other identified bacteria. To determine which bacteria could survive chlorination causing a potential health risk, the relative abundance of the intact cell community was characterized before and after chlorination. The dominant bacterial families in the intact community (non-chlorinated and chlorinated) were Xanthomonadaceae (21-17%) and Moraxellaceae (48-57%). Moraxellaceae were therefore more chlorine resistant than the other identified intact bacteria present.
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