Electrobioremediation of oil spills

Annually, thousands of oil spills occur across the globe. As a result, petroleum substances and petrochemical compounds are widespread contaminants causing concern due to their toxicity and recalcitrance. Many remediation strategies have been developed using both physicochemical and biological approaches. Biological strategies are most benign, aiming to enhance microbial metabolic activities by supplying limiting inorganic nutrients, electron acceptors or donors, thus stimulating oxidation or reduction of contaminants. A key issue is controlling the supply of electron donors/acceptors. Bioelectrochemical systems (BES) have emerged, in which an electrical current serves as either electron donor or acceptor for oil spill bioremediation. BES are highly controllable and can possibly also serve as biosensors for real time monitoring of the degradation process. Despite being promising, multiple aspects need to be considered to make BES suitable for field applications including system design, electrode materials, operational parameters, mode of action and radius of influence. The microbiological processes, involved in bioelectrochemical contaminant degradation, are currently not fully understood, particularly in relation to electron transfer mechanisms. Especially in sulfate rich environments, the sulfur cycle appears pivotal during hydrocarbon oxidation. This review provides a comprehensive analysis of the research on bioelectrochemical remediation of oil spills and of the key parameters involved in the process

Temporal variability and effect of environmental variables on airborne bacterial communities in an urban area of Northern Italy

Despite airborne microorganisms representing a relevant fraction of atmospheric suspended particles, only a small amount of information is currently available on their abundance and diversity and very few studies have investigated the environmental factors influencing the structure of airborne bacterial communities. In this work, we used quantitative PCR and Illumina technology to provide a thorough description of airborne bacterial communities in the urban area of Milan (Italy). Forty samples were collected in 10-day sampling sessions, with one sessionper season.Themeanbacterialabundancewasabout104 ribosomal operons perm3 of air andwas lower inwinter than in the other seasons. Communitieswere dominated by Actinobacteridae, Clostridiales, Sphingobacteriales and fewproteobacterial orders (Burkholderiales, Rhizobiales, Sphingomonadales andPseudomonadales).Chloroplastswere abundant in all samples. Ahigher abundanceof Actinobacteridae,which are typical soil-inhabiting bacteria, and a lower abundance of chloroplasts in samples collected on cold days were observed. The variation in community composition observed within seasons was comparable to that observed between seasons, thus suggesting that airborne bacterial communities showlarge temporal variability, even between consecutive days. The structure of airborne bacterial communities therefore suggests that soil and plants are the sources which contribute most to the airborne communities of Milan atmosphere, but the structure of the bacterial community seems to depend mainly on the source of bacteria that predominates in a given period of time

Biorisanamento di siti contaminati (Capitolo 12)

Questo testo nasce da un progetto che ha coinvolto un gruppo numeroso di docenti impegnati da anni sugli insegnamenti di Microbiologia ambientale nelle facolt\ue0 di Scienze biologiche e ambientali. Autori che hanno aderito con entusiasmo, per colmare un vuoto nella pubblicistica di settore e per fornire agli studenti uno strumento agile e, nel contempo, completo e utile per superare gli esami e per apprendere le basi fondamentali e le applicazioni della Microbiologia ambientale. La prima parte di questo libro affronta gli argomenti di ecologia microbica: dalla distribuzione dei microrganismi nei diversi ambienti naturali al ruolo nei cicli degli elementi, alle interazioni con altri organismi, ai processi di trasformazione dei metalli e dei composti organici naturali e di sintesi, trattandone sempre gli aspetti fisiologici, genetici e molecolari alla base delle diverse funzioni. Un ampio spazio \ue8 dedicato ai metodi e alle strategie per studi di ecologia microbica, con approfondimenti sui metodi molecolari per l\u2019analisi delle comunit\ue0 microbiche. La seconda parte \ue8 dedicata alle problematiche ambientali e alle applicazioni a salvaguardia dell\u2019ambiente, come i processi che riguardano il trattamento delle acque di scarico, le emissioni gassose, il biorisanamento di siti contaminati, il compostaggio dei rifiuti organici, l\u2019impatto della contaminazione ambientale sulla salute dell\u2019uomo, il biodeterioramento dei manufatti artistici. L\u2019ultimo capitolo tratta i principi di diritto ambientale che disciplinano le politiche ambientali, a livello locale, nazionale e comunitario

A New Biocatalyst for Production of Optically Pure Aryl Epoxides by Styrene Monooxygenase from Pseudomonas fluorescens ST

We developed a biocatalyst by cloning the styrene monooxygenase genes (styA and styB) from Pseudomonas fluorescens ST responsible for the oxidation of styrene to its corresponding epoxide. Recombinant Escherichia coli was able to oxidize different aryl vinyl and aryl ethenyl compounds to their corresponding optically pure epoxides. The results of bioconversions indicate the broad substrate preference of styrene monooxygenase and its potential for the production of several fine chemicals

Adverse biological effects of Milan urban PM looking for suitable molecular markers of exposure

The results presented summarise the ones obtained in the coordinated research project Tosca, which extensively analysed the impact of Milan urban PM on human health. The molecular markers of exposure and effects of seasonally and size-fractionated PMs (summer and winter PM10, PM2.5) were investigated in in vitro (human lung cell lines) and in vivo (mice) systems. The results obtained by the analyses of cytotoxic, pro-inflammatory and genotoxic parameters demonstrate that the biological responses are strongly dependent upon the PM samples seasonal and dimensional variability, that ultimately reflect their chemical composition and source. In fact summer PM10, enriched in crustal elements and endotoxins, was the most cytotoxic and pro-inflammatory fraction, while fine winter PMs induced genotoxic effects and xenobiotic metabolizing enzymes (like CYP1B1) production, likely as a consequence of the higher content in combustion derived particles reach in PAHs and heavy toxic metals. These outcomes outline the need of a detailed knowledge of the PMs physico-chemical composition on a local scale, coupled with the biological hazard directly associated to PM exposure. Apparently this is the only way allowing scientists and police-makers to establish the proper relationships between the respirable PM quantity/quality and the health outcomes described by clinicians and epidemiologists

In vitro effects of microbiologically characterized Milan particulate matter

AbstractMilan is one of the biggest cities in Italy characterized by a heavy automotive traffic. Air pollution is a deal of concern owing to the high concentration of particulate matter (PM10 and PM2.5) registered all over the year. Existing epidemiological data suggest an impact of PM on human health; however, experimental data on the biological effects of PM are still poorly investigated. In vitro results obtained after exposure to PM10 and PM2.5 sampled in Milan during winter and summer are reported here. PMs were characterized for their chemical and microbiological composition and tested to evaluate their potential toxicity in the human pulmonary cell line A549 and in the monocytes cell line THP-1. The chemical and microbiological analysis showed an evident seasonality in PM properties. Interestingly summer PMs contains mainly gram negative bacterial population while winter PMs gram positive, spore forming and possibly pathogenic, bacteria. PMs triggered different biological responses which are possibly related to the sampling season. Summer PMs elicited a higher pro-inflammatory potential that correlates to the high content of gram negative bacteria as detected by the microbiological characterization. On the other hand the winter PMs are able to induce cell cycle arrest, disrupting the normal microtubule organization in mitotic cells. The results obtained underline that the chemical properties of the PM are only in part responsible for the biological responses, since the biological components are of primary importance triggering endpoints such as inflammation

Remediation of groundwater polluted by gasoline-derived compounds with biobarriers

Biobarriers (BBs) are a new type of in situ technology for the remediation of contaminated groundwater. In this work results of laboratory experiments on a BB system are discussed. First, a proper filling material for BB applications was selected among four possible granular materials (perlite, pumice, expanded clay, activated carbon), based on the physical-chemical properties affecting the BB performance and the bacterial adhesion capacity. Based on the results, pumice was selected as the filling material for the second part of the work, during which a laboratory column test was carried out without inoculation. Physical-chemical parameters (temperature, dissolved oxygen concentration, pH and specific electric conductivity) and pollutant concentrations (BTEX, MTBE, tert-butyl alcohol, 1,2,4-trimetylbenzene, naphthalene) were measured in water samples collected from eight piezometers uniformly distributed along the column length. Molecular microbiological analyses were also carried out on pumice before and after the treatment to assess the differences in the bacterial community. Different decreasing trends in the pollutant concentration along the column were observed for the different groups of contaminants that found explanation in the distribution of the different microbial populations throughout the column