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The recent literature indicates that, depending on the feedstocks and pyrolysis temperature, biochar can be a good source of nutrients. On the contrary, some biochars are not good sources of available carbon and other nutrients, but their porous structure seems to be a suitable microenvironment for microbial colonization. We investigated the response of soil biological parameters, microbial biomass carbon and nitrogen (MBC and MBN), in relation to mobile N species. Five different biochars were produced at different temperatures (300, 350, 400, 450, and 500 °C) from the same feedstock (woodchips). The physicochemical and morphological characteristics of the individual biochar samples were described, and incubation was carried out with the application of 2% biochar to two different soil types (luvisol and fluvisol). The addition of 2% biochar did not change the pH in the slightly acid soils used in the experiment, in spite of the alkaline character of biochar. The increasing amounts of total and nitrate-available nitrogen during the experiment are probably related to changes in soil microbial activity. The amount of soluble carbon was constant during the experiment, confirming its stability in the soil, most likely because of the high amount of lignin in the feedstock. The influence of biochar on the soil microbiome was determined on the basis of the concentrations of MBC and MBN. Microbial biomass was increased in both soils treated with biochar produced at lower temperatures. The physicochemical characteristics of the biochar as well as the sorption behavior of N-NO3− and N-NH4+ indicate that at a pyrolysis temperature of 400 °C, biochar properties change substantially. However, these findings are only valid for biochar produced from woodchips, and the long-term effects of biochar application on soil properties need to be investigated in further studies.

Biostimulation of the activity of degrading autochthonous microbiota constitutes one of the most accepted bioremediation tools for oil-polluted soils. Applications of nutrients such as nitrogen fertilizers, oleophilic fertilizers or surfactants are some of the strategies employed. Soil microcosm experiments were performed in open glass containers to compare the biological activity of two types of soils: a sandy soil with low nutrient content and low biological activity and a clay loam soil with high nutrient content and high biological activity. Arabian crude oil was used as the contaminant, applied at 10,000 mg kg−1 and 20,000 mg kg−1. Different treatments were used including natural attenuation, used as a control, and the application of different biostimulation products. The results showed that for sandy soil at high hydrocarbon pollution, amendment with oleophilic fertilizer combined with a surfactant was the best treatment, whereas at low hydrocarbon pollution no significant differences were found among the treatments. In clay loam soil, at 10,000 mg kg−1 of hydrocarbon pollution, surfactant application was the most efficient treatment for total petroleum hydrocarbons removal. However, when Arabian crude oil was supplied at 20,000 mg kg−1, nitrogen, phosphorous, and potassium treatment and the oleophilic fertilizer S200C in combination with surfactant treatment presented the highest rate of total petroleum hydrocarbons removal. Thus, the suitability of biostimulation treatments was strongly influenced by the initial physicochemical and biological characteristics of the soil.

Sewage sludge composting is a profitable process economically viable and environmentally friendly. In despite of there are several kind of composting types, the use of combined system of semipermeable cover film and aeration air-floor is widely developed at industrial scale. However, the knowledge of the linkages between microbial communities structure, enzyme activities and physico-chemical factors under these conditions it has been poorly explored. Thus, the aim of this study was to investigate the bacterial dynamic and community structure using next generation sequencing coupled to analyses of microbial enzymatic activity and culturable dependent techniques in a full-scale real composting plant. Sewage sludge composting process was conducted using a semi-permeable Gore-tex cover, in combination with an air-insufflation system. The highest values of enzymatic activities such as dehydrogenase, protease and arylsulphatase were detected in the first 5 days of composting; suggesting that during this period of time a greater degrading activity of organic matter took place. Culturable bacteria identified were in agreement with the bacteria found by massive sequencing technologies. The greatest bacterial diversity was detected between days 15 and 30, with Actinomycetales and Bacillales being the predominant orders at the beginning and end of the process. Bacillus was the most representative genus during all the process. A strong correlation between abiotic factors as total organic content and organic matter and enzymatic activities such as dehydrogenase, alkaline phosphatase, and ß-glucosidase activity was found. Bacterial diversity was strongly influenced by the stage of the process, community-structure change was concomitant with a temperature rise, rendering favorable conditions to stimulate microbial activity and facilitate the change in the microbial community linked to the degradation process. Moreover, results obtained confirmed that the use of semipermeable cover in the composting of sewage sludge allow a noticeable reduction in the process-time comparing to conventional open windrows.

Extracellular polymeric substances (EPS) are one of the main components of microbial biofilms, which are markedly influenced by the chemical composition and functional properties of these EPS. This study quantified the adherence capacity of 29 bacterial strains isolated from marine water in Luria–Bertani and Bushnel-Haas culture media. Their capacity to produce EPS and the influence of the culture conditions on the chemical composition and emulsifying activity of their synthesised exopolymers was determined. Eighteen of the bacterial strains in this study produced EPS while eleven were unable to do so. Surface adherence was associated with bacterial growth and with the capacity of the isolates to synthesise EPS. Pseudoalteromonas elyakovii W18 showed the highest values for surface adherence and synthesised a non-bioemulsifier EPS. Principal component analysis (PCA) was used to establish the relationships between the biopolymer characteristics and surface adherence. The efficient adherence of P elyakovii on the surface of K1 (Anoxkaldnes©) carrier was confirming by scanning electronic microscopy.

The objective of this study was the development and design of a treatment system at a pilot-plant scale for the remediation of hydrocarbons in industrial wastewater. The treatment consists of a combined approach of absorption and biodegradation to obtain treated water with sufficient quality to be reused in fire defense systems (FDSs). The plant consists of four vertical flow columns (bioreactors) made of stainless steel (ATEX Standard) with dimensions of 1.65 × 0.5 m and water volumes of 192.4 L. Each bioreactor includes a holder to contain the absorbent material (Pad Sentec polypropylene). The effectiveness of the treatment system has been studied in wastewater with high and low pollutant loads (concentrations higher than 60,000 mg L−1 of total petroleum hydrocarbons (TPH) and lower than 500 mg L−1 of TPHs, respectively). The pilot-plant design can function at two different flow rates, Q1 (180 L h−1 ) and Q2 (780 L h−1 ), with or without additional aeration. The results obtained for strongly polluted wastewaters showed that, at low flow rates, additional aeration enhanced hydrocarbon removal, while aeration was unnecessary at high flow rates. For wastewater with a low pollutant load, we selected a flow rate of 780 L h−1 without aeration. Different recirculation times were also tested along with the application of a post-treatment lasting 7 days inside the bioreactor without recirculation. The microbial diversity studies showed similar populations of bacteria and fungi in the inlet and outlet wastewater. Likewise, high similarity indices were observed between the adhered and suspended biomass within the bioreactors. The results showed that the setup and optimization of the reactor represent a step forward in the application of bioremediation processes at an industrial/large scale., Compañía Logística de Hidrocarburos S.A

An autotrophic nitrogen removal bioreactor with granular biomass was exposed to high antibiotics concentration in order to evaluate its impact over the performance and the biomass of this bioprocess. A mixture of azithromycin, norfloxacin, trimethoprim and sulfamethoxazole caused loss of autotrophic nitrogen removal performance, coupled to a deep change in the bacterial community diversity and structure of the granular biomass. Azithromycin, norfloxacin and trimethoprim were efficiently removed in the CANON bioreactor, reducing its concentration 77.9 ± 11.2%, 51.7 ± 10.7% and 57.8 ± 8.1%, respectively. The granular biomass changed significantly with the addition of the antibiotics, decreasing in settling velocity but increasing in compactness, losing its inner porous structure but developing a protective outer layer build of cell material. Prolonged operation under the antibiotics loading promoted the adaptation of multi-drug resistant fungus Scedosporium boydii fungal species and of Acidovorax ebreus TPSY , Alcaligenes aquatilis , Paracoccus versutus or Ochrobactrum antropii , which have been identified as human, animal and/or plant pathogens.

This study evaluated the composting process of a mixture of sewage sludge and bulking agent in a semi-closed system at industrial scale, which consisted of an aerated static windrow covered with a semi-permeable film. Physical-chemical and respirometric variables were studied and bacteria and fungi were monitored to assess the improvement in the composting process. The system was compared with conventional open windrows in which lengthy composting times are required to obtain stabilized compost, compost sanitation is not always reached and periodical turning must be carried out to avoid anaerobic conditions. The high temperatures reached and maintained during the stage under the semi-permeable film (≈80 °C) permitted the sanitation of the compostable substrate, as demonstrated by the rapid disappearance of Salmonella sp. and the decrease in Escherichia coli in only 5 days of the process. The total microorganism concentration also decreased during the composting process. The rapid decrease in carbon content expressed in volatile solids (VS) (around 41%) showed that the composting process carried out under the semi-permeable film could be shortened to 30 days. The evolution of thermophilic and mesophilic bacteria and fungi was conditioned by the windrow temperature and the biodegradable organic matter content. An adequate linear correlation (r2 = 0.9214) between the total microorganism concentration (log CFU/g) and VS (%) was obtained during the composting process.

The addition of compost from sewage sludge to soils represents a sustainable option from an environmental and economic point of view, which involves the valorisation of these wastes. However, before their use as a soil amendment, compost has to reach the quality levels according to the normative, including microbial parameters. Viruses are not included in this regulation and they can produce agricultural problems and human diseases if the compost is not well sanitised. In this study, we carried out the analysis of the viral populations during a composting process with sewage sludge at an industrial scale, using semipermeable cover technology. Viral community was characterised by the presence of plant viruses and bacteriophages of enteric bacteria. The phytopathogen viruses were the group with the highest relative abundance in the sewage sludge sample and at 70 days of the composting process. The diversity of bacterial viruses and their specificity, with respect to the more abundant bacterial taxa throughout the process, highlights the importance of the interrelations between viral and bacterial communities in the control of pathogenic communities. These results suggest the possibility of using them as a tool to predict the effectiveness of the process.

Polycyclic aromatic hydrocarbons (PAHs) are recalcitrant compounds resulting from both natural and anthropogenic processes, distributed in all environments worldwide. In soils, PAHs can remain for decades, absorbed into the soil particles and organic matter and, thus, inaccessible to microbial degradation. Microbial fungi are well suited for terrestrial habitats and can reach xenobiotic compounds in soil due to their multicellular mycelium. In general, fungi contribute to the overall microbial population in soils, allowing the transport and interaction with other communities. However, these communities have proven difficult to observe in conventional biotic studies. As such, the behavior of fungal communities in PAH-polluted soils remains poorly studied. Deeper knowledge could help to identify key drivers of bioremediation under different conditions for further application in real-world scenarios, including conditions obtained using cell culture techniques. This review serves to present an overview of the role of fungi in aromatic hydrocarbon degradation and the importance of the study of fungal functional diversity to understand the process of xenobiotic removal.

This study describes the capacity of different sorbents to form stable biofilms under highly hydrocarbon-polluted conditions and the degrading capacity of the microbiota present in the biofilm. With this aim, microcosms were designed in a 1 L beaker with 400 mL of culture medium or polluted wastewater and an amount equivalent of 200 mL of the selected sorbent carrier, made of cork and/or polypropylene meltblown. The culturable bacteria adhered to the sorbent carrier were quantified, and the time course of the hydrocarbon concentration was studied together with the formation of a biofilm on the carrier’s surface. The results revealed a different performance of the carriers in terms of bacterial adhesion, significantly reduction in the hydrocarbon content in water at the end of the assays, and a biofilm tolerance to high hydrocarbon concentration in the polluted water. From these results, it was concluded that the use of a sorbent, hydrophobic cork, or meltblown polypropylene, together with indigenous microbiota, constitutes a promising technology for the treatment of hydrocarbon-polluted water.

López-Goñi, Ignacio et al., Social networks are already being exploited for searching, storing, and sharing knowledge, demonstrating that they are an efficient vehicle for social learning. Consequently, they could be implemented as a competent tool for formal learning. Twitter is among the 10 most popular online social networks, integrating a community of over 500 million users around the world. Twitter has already been used in several educational programs and evaluated as a positive teaching experience with an outstanding potential in academic and educational environments (1–6). However, there are scarce examples available in the literature about its use in science teaching and communication. In this work, we present and analyze the application of Twitter to create an online space for communication and learning of basic microbiology. With this aim, a team of professionals in the field has imparted, to our knowledge, the first worldwide open access microbiology course via Twitter. Here we assess the results of our experience of using this social network as a tool for teaching, promoting, and communicating scientific knowledge to a wide audience.

In the present study, physico-chemical characteristics, heavy metals content, odour emissions, microbial enumeration and enzymatic activities were analysed during industrial scale composting of sewage sludge partially pre-treated to evaluate the effect of a combined system of semi-permeable film and aeration on these parameters. The results related to physico-chemical parameters showed a decrease in total organic carbon (TOC), organic matter (OM), total carbon (TC) along the process. Volatile solids (VS) were also reduced, reaching 36% at 120 days, which is above the limit according to the current legislation. Similarly, metal content was found to be an important variable in the evolution of enzymatic activity, while lead (Pb), zinc (Zn), and nickel (Ni) were the most influential. Moreover, heavy metals were found below the limit of type B compost quality or European class 2 at the end of the process, which is suitable for agriculture soil. The odorous impact generated during the hydrolytic stage was reduced to an average value of 4 ouE/s. This suggests that, covered stage with the semi-permeable film, could be a viable solution to mitigate odour emissions. The highest temperature was reached at 10 days and it was favoured by semi-permeable film. Temperature promoted the presence of thermophilic bacteria and fungi and indicated an early biodegradation process mediated by microorganisms. Statistical analyses revealed a high correlation of physico-chemical variables with microbial activity. Thus, samples from the first 14 days were highly correlated with enzymatic activities such as β-glucosidase (Ac-βGlu), protease (Ac-Pr), and dehydrogenase (Ac-De), which have usually been involved in the hydrolysis of organic matter.