The ecology of complex microhabitats remains poorly characterized in most tropical and subtropical biomes, and holds potential to help understand the structure and dynamics of different biodiversity components in these ecosystems. We assessed nutritional and metabolic parameters of two bromeliad species (Aechmea gamosepala and Vriesea platynema) at an Atlantic Forest site and used 16S rDNA metabarcoding to survey the microbial communities inhabiting their tanks. We observed that levels of some nutrients (e.g., nitrogen) varied across seasons consistently in both species, while others (e.g., phenolic compounds) presented considerable differences between the two bromeliads. In contrast, patterns of tank microbial diversity did not follow a similar temporal trend. There was extensive variation in microbial composition among samples, which included intra-specific differences but also some consistent differences between the two bromeliads. For example, Citrobacter, Klebsiella and Pantoea presented significantly different abundances in the two species. Interestingly, the dominant bacterial genera in both species included Pseudomonas and Enterobacter, which have been reported to include plant-beneficial species. Overall, our data contribute to the characterization of the nutritional status of Atlantic Forest bromeliads and the composition of their prokaryotic communities, laying the foundation for detailed investigations targeting the ecological interactions between these plants and their associated microbes.

The chemical properties, ecotoxicity, and microbiome of leachates from phytomanaged Cu-contaminated soils were analyzed. The phytomanagement was carried out using Cu-tolerant poplar Populus trichocarpa × deltoides cv. Beaupré and black bent Agrostis gigantea L., aided by soil amendments, i.e., dolomitic limestone (DL) and compost (OM), alone and in combination (OMDL). Plants plus either DL or OMDL amendments reduced in leachates the electrical conductivity, the Cu concentration, and the concentration of total organic C except for the OMDL treatment, and decreased leachate toxicity towards bacteria. Total N concentration increased in the OM leachates. The aided phytostabilization increased the culturable bacteria numbers and the proportion of Cu-resistant bacteria in the leachates, as compared to the leachate from the untreated soil. Phytomanagement also enriched the microbial communities of the leachates with plant beneficial bacteria. Overall, the Cu stabilization and phytomanagement induced positive changes in the microbial communities of the soil leachates.

Theactive sludge process is one of the most-used techniques for the biodegradation of organic compounds present in effluents from an assortment of wastewaters. This study investigated the bacterial community structure of a petroleum industry’s activated sludge and its physical and chemical parameters using high-throughput sequencing. Samples were collected over one year: autumn 2015 (C1), winter 2015 (C2), spring 2015 (C3), and summer 2016 (C4). Total DNA was extracted, and the primers targeting the V4 region of the 16S rRNA gene were used for amplicon sequencing. The majority of the detected microorganisms were considered rare microbiota, presenting a relative abundance below 1% of the total sequences. All of the sequences were classified at the phylum level, and up to 55% of the ASVs (Amplicon Sequence Variants) were associated with known bacterial genera. Proteobacteria was the most abundant phylum in three seasons, while the phylum Armatimonadota dominated in one season. The genus Hyphomicrobium was the most abundant in autumn, winter and summer, and an ASV belonging to the family Fimbriimonadaceae was the most abundant in the spring. Canonical Correspondence Analysis showed that physicochemical parameters of SS, SD and TSS are correlated, as well as ammoniacal nitrogen. Sample C3 presented the highest values of COD, AN and solids (SS, SD and TSS). The highest COD, AN, and solids values are correlated to the high frequency of the phylum Armatimonadota in C3.

Mycolicibacterium gadium IBE100 and Mycobacterium paragordonae IBE200 are aerobic, chemoorganoheterotrophic bacteria isolated from activated sludge from a wastewater treatment plant. They use 2‐methylpropene (isobutene, 2‐MP) as the sole source of carbon and energy. Here, we postulate a degradation pathway of 2‐methylpropene derived from whole genome sequencing, differential expression analysis and peptide‐mass fingerprinting. Key genes identified are coding for a 4‐component soluble diiron monooxygenase with epoxidase activity, an epoxide hydrolase, and a 2‐hydroxyisobutyryl‐CoA mutase. In both strains, involved genes are arranged in clusters of 61.0 and 58.5 kbp, respectively, which also contain the genes coding for parts of the aerobic pathway of adenosylcobalamin synthesis. This vitamin is essential for the carbon rearrangement reaction catalysed by the mutase. These findings provide data for the identification of potential 2‐methylpropene degraders.