home Journal club New papers on Microbiology of the Built Environment, December 10, 2016

New papers on Microbiology of the Built Environment, December 10, 2016

Microbes on buildings

Analysis of dark crusts on the church of Nossa Senhora do Carmo in Rio de Janeiro, Brazil, using chemical, microscope and metabarcoding microbial identification techniques – Christine Gaylarde – International Biodeterioration & Biodegradation ($35.95)

Old Cathedral of Rio de Janeiro, source: Wikipedia

The dark crust on the surface of the Nossa Senhora do Carmo church, in the centre of Rio de Janeiro, was shown to contain high salt levels and neogypsum above the original granite. (…). Next generation DNA sequencing techniques were used for the first time to determine the total microbial populations that could be involved in surface deterioration of historic stone buildings in a tropical climate. High levels of halophilic and stress-resistant bacteria and fungi were identified, able to grow at high temperatures, salt and UV levels, and in the presence of low moisture and toxic fossil fuel emissions. Many produced pigments, adding to the discoloration of the stone surface. (…) Salt content appeared to be a major driving factor in community structure. This microbial population participated strongly in crust, formation. The final results of biofilm formation on the stone are surface discoloration, induration and degradation of the façade.

Microbes and agriculture

Review: Microbes in the Anthropocene: spillover of agriculturally selected bacteria and their impact on natural ecosystems – Thomas Bell – Proceedings of the Royal Society B (OA)

Illustration of some of the hypotheses discussed in the main text

Soil microbial communities are enormously diverse, with at least millions of species and trillions of genes unknown to science or poorly described. Soil microbial communities are key components of agriculture, for example, in provisioning nitrogen and protecting crops from pathogens, providing overall ecosystem services in excess of $1000bn per year. It is important to know how humans are affecting this hidden diversity. Much is known about the negative consequences of agricultural intensification on higher organisms, but almost nothing is known about how alterations to landscapes affect microbial diversity, distributions and processes. We review what is known about spatial flows of microbes and their response to land-use change, and outline nine hypotheses to advance research of microbiomes across landscapes. (…)

Microbes and polllution

Impact of wastewater treatment plant discharge on the contamination of river biofilms by pharmaceuticals and antibiotic resistance – Elodie Aubertheau – Science of the Total Environment ($41.95)

Graphical abstract

Wastewater treatment plants (WWTPs) are one of the main sources of pharmaceutical residue in surface water. Epilithic biofilms were collected downstream from 12 WWTPs of various types and capacities to study the impacts of their discharge through the changes in biofilm composition (compared to a corresponding upstream biofilm) in terms of pharmaceutical concentrations and bacterial community modifications (microbial diversity and resistance integrons). The biofilm is a promising indicator to evaluate the impacts of WWTPs on the surrounding aquatic environment. Indeed, the use of biofilms reveals contamination hot spots. All of the downstream biofilms present significant concentrations (up to 965 ng/g) of five to 11 pharmaceuticals (among the 12 analysed). Moreover, the exposition to the discharge point increases the presence of resistance integrons (three to 31 fold for Class 1) and modifies the diversity of the bacterial communities (for example cyanobacteria). The present study confirms that the discharge from WWTPs has an impact on the aquatic environment.

Microorganisms isolated from polluted urban soils highly effectives in degrading recalcitrant pesticides – Liliana Rocío Botero-Botero – Revista Facultad de Ingeniería (OA)

Degradation of chlorpyrifos, malathion, and methyl parathion

Between 1972 and 1984 all types of solid waste from the city of Medellin (note: in Colombia, EB) were deposited in an area which had no technical specification as a landfill. Domestic, hospital
and industrial waste was deposited, and accumulated to form a mountain of waste more than 10 meters high. To exacerbate the problem, when the site was closed for the deposit of solid waste, people remained living there to recycle materials. (…) Microbial
consortia isolated from Moravia soils (MS) showed a high capacity to degrade chlorpyrifos, methyl parathion and malathion pesticides (20, 30 and 130 mg Kg-1). To provide a point of comparison, the degradation of the 3 pesticides was also performed with isolated pools of
immature compost. The MS microbial consortia showed higher degradation rates than CI
microbial consortia when malathion, methyl parathion and chlorpyrifos were degraded.

Isolation and Characterization of Acrylamidase from Arthrobacter sp. DBV1 and Its Ability to Biodegrade Acrylamide – Dattatray K. Bedade – Applied Biochemistry and Biotechnology ($39.95)

Image credit: FoodNavigator.com / ZerborA

Although acrylamide finds diverse industrial applications, its presence in the environment is hazardous due to its carcinogenic, neurotoxic, and teratogenic properties. In spite of the general toxicity of acrylamide in the monomer form, some microorganisms are able to use it as a source of energy by catabolizing it to ammonia and acrylic acid by means of acrylamidase (EC 3.5.1.4). The present work reports on a novel soil isolate as an acrylamide-degrading bacteria. Based on biochemical characterization and 16S ribosomal RNA (rRNA) gene sequence, the bacterial strain was identified as Gram-positive Arthrobacter sp. DBV1. (…) These finding suggests that the strain could be attractive for biodegradation of acrylamide from the environment and also possibly from foods containing preformed acrylamide.

Sequential bioleaching of copper from brake pads residues using encapsulated bacteria – François Vermeulen – Minerals Engineering ($39.95)

Image credit: CopperFreeBrakes.org

Bioleaching of copper from pure granular shots and from a “pre-consumer” secondary resource from automotive industry (Brake Pads Powder, “BPP”) was carried out in a comparative study with conventional planktonic and PVA-encapsulated micro-organisms using a mixed culture of iron oxidizing bacteria: A. ferrooxidans, L. ferrooxidans and L. ferriphilum. The global process is characterized as “sequential” since a preliminary acid leaching is performed for ferrous iron extraction from the BPP material before the copper bioleaching itself.(…) Cell immobilization offers complementary benefits as continuous process and permanent bacteria acclimation. This technology presents an interesting alternative to conventional planktonic and “two-step” processes.

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Elisabeth Bik

After receiving my PhD at Utrecht University in The Netherlands, I worked at the Dutch National Institute for Health and the St. Antonius Hospital in Nieuwegein. In 2001, I joined the Department of Microbiology and Immunology at Stanford, where I have worked on the characterization of the microbiome of human oral, gastric, and intestinal samples, as well as samples from marine mammals. Since November 2016, I am the new Science Editor at uBiome, a microbiome genomics company enabling citizen science. But you might also find me working on the detection of science misconduct, at my blog Microbiome Digest , an almost daily compilation of scientific papers in the rapidly growing microbiome field, on Twitter at @MicrobiomDigest.

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