Impact of pollution on the microbial diversity of a tropical river in an urbanized region of northeastern Brazil

Rivers are important ecosystems that are integrated into biogeochemical cycles and constitute an essential resource for numerous human uses. However, the assessment of the biological diversity and composition of microbial communities found in rivers remains incomplete, partly due to methodological constraints which are only recently being resolved with the advent of next generation sequencing (NGS) techniques. Using 454-pyrosequencing of the 16S gene, the present study analyzed the microbial diversity of the planktonic and sediment populations in a tropical river in northeastern Brazil that is exposed to severe pollution. Six water and six sediment samples were analysed. The dominant bacterial phyla in both sediment and water were the Proteobacteria, followed by Bacteroidetes and Actinobacteria in the water column and by Chloroflexi and Acidobacteria in the sediment. Biological diversity appeared to be greatly decreased by environmental pollution, whereas the microbial community structure was variable across the analyzed transect. Moreover, a narrow relationship between industrial and urban sources of contamination and the bacterial genera detected at these sites has been observed. A variety of potentially pathogenic bacteria was detected, including Klebsiella, Treponema, Faecalibacterium and Enterococcus, indicating that the river might pose a substantial risk to public health. [Int Microbiol 20(1): 11-24 (2017)]Keywords: environmental pollution · river plankton microbiota · biodiversit

Enhanced Production of 1,3‑Propanediol by Glycerol Fermentation Using an Attached‑to‑Silicone Bioflm Reactor

Glycerol fermentation for 1,3-propanediol (1,3-PDO) production was studied in an anaerobic up-flow reactor with biomass attached to silicone support. A mixed microbial culture was activated to perform the biofilm formation and attachment to a silicone hose prior the reactor operation. The reactor was operated over 362 days divided into two phases (P). In P1 and P2, the reactor was continuously fed with pure and crude glycerol, respectively. The operation consisted of increasing the glycerol loading rates (gly-LR). The achieved highest 1,3-PDO average yields were 0.43 mol mol-gly−1 and 0.62 mol mol-gly−1 when applied gly-LR was 18 and 46 g L−1 d−1 in P1 and P2, respectively. A maximum 1,3-PDO productivity of 14.7 g L−1 d−1 was obtained in P2. The higher yields of 1,3-PDO when the feed changed from pure to crude glycerol indicated a change in the microbial community. These results show that the studied system can be very promising and cost-effective for converting crude glycerol into value-added products on large scale even at high loadsThis study was funded by Spanish Ministry of Science and Innovation (Grant no: PID2019-104812GBI00X), UAM-Santander Inter-university Cooperation Projects with Latin America (CEAL-AL/2017-14), and CAPES-PrInt (fnance code 001, Process no 88887.467533/2019-00

Aspectos físico-químicos e biológicos relacionados à ocorrência de Biomphalaria glabrata em focos litorâneos da esquistossomose em Pernambuco

This study analyzes the physico-chemical and biological parameters of freshwater aquatic environments in coastal areas of the State of Pernambuco, Brazil, where snail vector foci and cases of schistosomiasis have been recorded. The tests were carried out using standard methods and sediments were analyzed using the X-ray fluorescence technique. The micro-algae were analyzed using conventional microscopy. The most abundant chemical elements in the sediments were Fe, Ca, Si and Al and there were high concentrations of electrolytes in comparison with data published in the literature. The mean values for salinity (7.7 g/L) and sulfate (489 mg/L) were much higher than normal for freshwater environments. The micro-algae identified are those that inhabit environments with higher levels of salinity. The snail Biomphalaria glabrata seems, therefore, to be more tolerant to salty environments and this constitutes a risk of spread of schistosomiasis