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Background Worldwide, pleural infections are becoming more common. Overuse of empirical antibiotics has been linked to longer hospital stays and higher death rates, causing the emergence of antibiotic-resistant pathogens. So, proper care requires the identification of the pathogenic bacteria using pleural fluid culture. In addition to normal culture, pleural fluid inoculation in blood culture bottles enhances the proportion of patients with detectable infections in less time. Aim To assess whether inoculating pleural fluid into a blood culture bottle will increase the yield of isolated pathogens compared to routine culture techniques in evaluating pleural infection. Also, to compare the time of pathogen detection when comparing the detection by blood culture bottle versus the routine microbiological culture technique. Recognize the distribution of isolated bacteria from our center and their susceptibility profile to different antibiotics and predict the most effective empirical antibiotics. Patients and methods Cross-sectional analytical prospective study conducted at the Department of Pulmonology and Clinical Pathology in Cairo University Hospitals. It included 70 patients with infected pleural effusion. Under ultrasound supervision, pleural fluid was extracted and transported to the laboratory for routine microbiological culture. At the same time, an automated blood culture bottle was inoculated with 5–10 ml to be incubated. All the detected pathogens were identified and tested for antimicrobial susceptibility according to CLSI. Results The mean age of our patients was 47.1 ± 15.6 years. Empyema was documented in 16 (22.9%) of our patients, whereas 54 (77.1%) had exudative pleural effusion. Positive aerobic infection in blood culture bottle was seen in 37 patients, compared to 21 patients in direct pleural culture. A statistically significant difference was found between the culture positive rate in aerobic blood culture bottles and direct pleural culture (P=0.001). Conclusion Blood culture bottle inoculation of infected pleural fluid increases the sensitivity of microbial yield in a shorter time than standard culture.

Background: Worldwide, pleural infections are becoming more common. Overuse of empirical antibiotics has been linked to longer hospital stays and higher death rates, causing the emergence of antibiotic-resistant pathogens. So, proper care requires the identification of the pathogenic bacteria using pleural fluid culture. In addition to normal culture, pleural fluid inoculation in blood culture bottles enhances the proportion of patients with detectable infections in less time. Aim: To assess whether inoculating pleural fluid into a blood culture bottle will increase the yield of isolated pathogens compared to routine culture techniques in evaluating pleural infection. Also, to compare the time of pathogen detection when comparing the detection by blood culture bottle versus the routine microbiological culture technique. Recognize the distribution of isolated bacteria from our center and their susceptibility profile to different antibiotics and predict the most effective empirical antibiotics. Patients and methods: Cross-sectional analytical prospective study conducted at the Department of Pulmonology and Clinical Pathology in Cairo University Hospitals. It included 70 patients with infected pleural effusion. Under ultrasound supervision, pleural fluid was extracted and transported to the laboratory for routine microbiological culture. At the same time, an automated blood culture bottle was inoculated with 5–10 ml to be incubated. All the detected pathogens were identified and tested for antimicrobial susceptibility according to CLSI. Results: The mean age of our patients was 47.1 ± 15.6 years. Empyema was documented in 16 (22.9%) of our patients, whereas 54 (77.1%) had exudative pleural effusion. Positive aerobic infection in blood culture bottle was seen in 37 patients, compared to 21 patients in direct pleural culture. A statistically significant difference was found between the culture positive rate in aerobic blood culture bottles and direct pleural culture (P =0.001). Conclusion: Blood culture bottle inoculation of infected pleural fluid increases the sensitivity of microbial yield in a shorter time than standard culture. [ABSTRACT FROM AUTHOR]

Bioindicator species are used to assess the damage and magnitude of possible impacts of anthropic origin on the environment, such as the reckless consumption of antimicrobials. Chelonia mydas has several characteristics that make it a suitable bioindicator of marine pollution and of the presence of pathogens that cause diseases in humans. This study aimed to investigate the green sea turtle as a reservoir of resistant bacteria, mainly because C. mydas is the most frequent sea turtle species in Brazilian coastal regions and, consequently, under the intense impact of anthropic factors. Free-living green sea turtles ranging from 42.8 to 92 cm (average = 60.7 cm) were captured from Itaipú Beach, Brazil. Cloaca samples (characterizing the gastrointestinal tract) and neck samples (representing the transient microbiota) were collected. Bacterial species were identified, and their was resistance associated with the antimicrobials cephalothin, ciprofloxacin, gentamicin, tetracycline, and vancomycin. Citrobacter braaki, Klebsiella oxytoca, K. variicola and Proteus mirabilis were found resistant to cephalothin and Morganella morganii and Enterococcus faecalis tetracycline-resistant isolates in cloaca samples. In neck samples, species resistant to tetracycline were Salmonella sp., Serratia marcescens, S. ureylitica and Proteus mirabilis. This data reinforces that the green turtle is a bioindicator of antimicrobial resistance (AMR). [ABSTRACT FROM AUTHOR]

The environmental variations and their interactions with the biosphere are vital in the Arctic Ocean during the summer sea-ice melting period in the current scenario of climate change. Hence, we analysed the vertical distribution of bacterial and archaeal communities in the western Arctic Ocean from sea surface melt-ponds to deep water up to a 3040 m depth. The distribution of microbial communities showed a clear stratification with significant differences among different water depths, and the water masses in the Arctic Ocean – surface mixed layer, Atlantic water mass and deep Arctic water – appeared as a major factor explaining their distribution in the water column. A total of 34 bacterial phyla were detected in the seawater and 10 bacterial phyla in melt-ponds. Proteobacteria was the dominant phyla in the seawater irrespective of depth, whereas Bacteroidota was the dominant phyla in the melt-ponds. A fast expectation-maximization microbial source tracking analysis revealed that only limited dispersion of the bacterial community was possible across the stratified water column. The surface water mass contributed 21% of the microbial community to the deep chlorophyll maximum (DCM), while the DCM waters contributed only 3% of the microbial communities to the deeper water masses. Atlantic water mass contributed 37% to the microbial community of the deep Arctic water. Oligotrophic heterotrophic bacteria were dominant in the melt-ponds and surface waters, whereas chemoautotrophic and mixotrophic bacterial and archaeal communities were abundant in deeper waters. Chlorophyll and ammonium were the major environmental factors that determined the surface microbial communities, whereas inorganic nutrient concentrations controlled the deep-water communities. [ABSTRACT FROM AUTHOR]

The large number of dormant microorganisms present in the environment is an important component of microbial diversity, and neglecting dormant microorganisms would be disruptive to all research under the science of microbial diversity. However, current methods can only predict the dormancy potential of microorganisms in a sample and are not yet able to monitor dormant microorganisms directly and efficiently. Based on this, this study proposes a new method for the identification of dormant microorganisms based on high-throughput sequencing technology: Revived Amplicon sequence variants (ASV) Monitoring (RAM). Pao cai (Chinese fermented vegetables) soup was used to construct a closed experimental system, and sequenced samples were collected at 26 timepoints over a 60-day period. RAM was used to identify dormant microorganisms in the samples. The results were then compared with the results of the currently used gene function prediction (GFP), and it was found that RAM was able to identify more dormant microorganisms. In 60 days, GFP monitored 5045 ASVs and 270 genera, while RAM monitored 27,415 ASVs and 616 genera, and the RAM results were fully inclusive of the GFP results. Meanwhile, the consistency of GFP and RAM was also found in the results. The dormant microorganisms monitored by both showed a four-stage distribution pattern over a 60-day period, with significant differences in the community structure between the stages. Therefore, RAM monitoring of dormant microorganisms is effective and feasible. It is worth noting that the results of GFP and RAM can complement and refer to each other. In the future, the results obtained from RAM can be used as a database to extend and improve the monitoring of dormant microorganisms by GFP, and the two can be combined with each other to build a dormant microorganism detection system. [ABSTRACT FROM AUTHOR]

The damaging competition between crops and parasitic weeds has a negative impact on agricultural productivity; however, the impact of disturbance on the soil's microbial community has received less attention. Hence, this study investigates the microbial composition and diversity of the maize rhizosphere infected with Striga hermonthica using a shotgun sequencing approach from two maize-growing fields (Eruwa, Nigeria and Mbuzini, South Africa). The rhizosphere soil DNA was extracted from infested soil using a Nucleospin soil genomic DNA extraction kit and sequenced on an Illumina platform. The dominant phyla were Actinobacteria, Bacteroidetes, Deinococcus-Thermus, Acidobacteria, Chloroflexi, Cyanobacteria, Planctomycetes, Verrucomicrobia, Chlorobi, Proteobacteria, Firmicutes, Nitrospirae, Thermotogae, Synergistetes, Ascomycota, Euryarchaeota, and Crenarchaeota. Bacteria phyla were observed to be of higher proportion in the rhizosphere soil samples obtained from Striga-infested maize field in Eruwa (Es) than those recovered from Mbuzini (Ms). The alpha diversity of microbial communities indicated insignificance differences (p > 0.05) between the five taxonomical groups (phylum, class, order, family, and genus), while the beta diversity produced a significant (p = 0.01, R = 0.52) difference in the microbial diversity of the infested soil. In summary, the study sheds light on the diversity and composition of the microbiome of Striga hermonthica-infested soil, which influences the microbial functions in the management and sustenance of plant health against parasitic weeds. [ABSTRACT FROM AUTHOR]

The knowledge about the microbial diversity of different olives varieties from diverse regions in the Mediterranean basin is limited. This work aimed to determine the microbial diversity of three different fermented olive varieties, collected from different regions in Cyprus, via Next Generation Sequencing (NGS) analysis. Olives were spontaneously fermented for 120days, microbial DNA was extracted from the final products, and subjected to 16S rRNA gene and ITS1 loci metabarcoding analysis for the determination of bacterial and fungal communities, respectively. Results revealed that the bacterial profile of the studied varieties was similar, while no noteworthy differences were observed in olives from different regions. The bacterial profile was dominated by the co-existence of Lactobacillus and Streptococcus, while the genera Lactococcus and Salinivibrio and the family Leuconostocaceae were also present in increased relative abundances. Regarding fungal communities, the analysis indicated discrimination among the different varieties, especially in Kalamata ones. The most abundant fungi were mainly the genera Aspergillus, Botryosphaeria, Meyerozyma, and Zygosaccharomyces for Cypriot olives, the genera Botryosphaeria, Saccharomyces, Geosmithia, and Wickeromyces for Kalamata variety, while the dominant fungi in the Picual variety were mainly members of the genera Candida, Penicillium, Saccharomyces, Hanseniospora and Botryosphaeria. Potential microbial biomarkers that distinguish the three varieties are also proposed. Moreover, interaction networks analysis identified interactions among the key taxa of the communities. Overall, the present work provides useful information and sheds light on an understudied field, such as the comparison of microbiota profiles of different varieties from several regions in Cyprus. The study enriches our knowledge and highlights the similarities and the main differences between those aspects, booming in parallel the need for further works on this frontier, in the attempt to determine potentially olives’ microbial terroir in Cyprus. Our work should be used as a benchmark for future works in this direction. [ABSTRACT FROM AUTHOR]

Enhanced nitrogen removal by hydroxylamine (NH 2 OH) on anammox-related process recently received attention. This study investigated the impact of NH 2 OH on the partial-denitrification/anammox (PDA) biosystem. Results show that NH 2 OH (≤10 mg N/L) immediately induced nitrite accumulation and provided sufficient NO 2 - to anammox, achieving a 18.1 ± 4.3 % increase of nitrogen removal efficiency compared to the absence of NH 2 OH. Long-term exposure to NH 2 OH accelerated the functional microbial community transformation to PDA. Thauera was highly enriched (6.1 % → 26.9 %) along with Candidatus Brocadia increased in the biofilms, which mainly favor the coupling process of nitrate reduction and anammox. Although the migration mechanism of anammox and denitrifier revealed by CLSM-FISH alleviates the adverse effects of NH 2 OH, the anammox was inhibited when NH 2 OH exceeding 15 mg N/L through destroying the inner reduction of NO 2 - . These results suggested appropriate NH 2 OH addition favors the synergy between denitrifying and anammox bacteria, providing a promising option for wastewater treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Anammox granules harbor a variety of bacteria, with each granule layer providing a niche for bacteria with specific metabolic functions. To investigate microbial distribution, nitrogen transformation rates, and extracellular polymeric substance (EPS) content across the depth layers of anammox granules, granules sized 0.9-2.0 mm were sheared into seven layers. The outer layers exhibited higher anammox bacterial abundance (9.9 %) than the inner layers (8.1 %). In contrast, the abundance of denitrifying bacteria increased from 25.0 % in outer layers to 34.9 % in inner layers. Nitrifying bacteria, along with heterotrophic nitrifying and aerobic denitrifying bacteria, were predominantly found in outer layers. Despite the higher EPS content in inner layers, denitrification rates remained low across all layers, likely due to limited carbon availability from microbial lysis or EPS. These findings offer valuable insights into the niche distribution of microbial communities within anammox granules., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Bioindicator species are used to assess the damage and magnitude of possible impacts of anthropic origin on the environment, such as the reckless consumption of antimicrobials. Chelonia mydas has several characteristics that make it a suitable bioindicator of marine pollution and of the presence of pathogens that cause diseases in humans. This study aimed to investigate the green sea turtle as a reservoir of resistant bacteria, mainly because C. mydas is the most frequent sea turtle species in Brazilian coastal regions and, consequently, under the intense impact of anthropic factors. Free-living green sea turtles ranging from 42.8 to 92 cm (average = 60.7 cm) were captured from Itaipú Beach, Brazil. Cloaca samples (characterizing the gastrointestinal tract) and neck samples (representing the transient microbiota) were collected. Bacterial species were identified, and their was resistance associated with the antimicrobials cephalothin, ciprofloxacin, gentamicin, tetracycline, and vancomycin. Citrobacter braaki, Klebsiella oxytoca, K. variicola and Proteus mirabilis were found resistant to cephalothin and Morganella morganii and Enterococcus faecalis tetracycline-resistant isolates in cloaca samples. In neck samples, species resistant to tetracycline were Salmonella sp., Serratia marcescens, S. ureylitica and Proteus mirabilis. This data reinforces that the green turtle is a bioindicator of antimicrobial resistance (AMR).

A total of 68 315 digitised records of myxomycetes from the eastern United States were compiled from all readily available sources. After cleaning the database for inconsistencies, 58 594 records remained that were suitable for analysis. A total of 460 different species of myxomycetes were recorded, out of which 410 were classified as rare. Five species were represented by more than 1 500 records and 44 species were represented by only a single record. The states of New York, Virginia and West Virginia have the highest number of records. Almost half of the recognised morphospecies of myxomycetes in the world occur in the eastern United States. A small number of species thrive in different ecological conditions, whereas most species require more specific ecological settings for the formation of fruiting bodies. States associated with high biodiversity have been subjected to more intensive sampling efforts, and southern states seem to have been less studied than northern ones. The project described herein apparently represents one of the few efforts to characterise the myxobiota of a relatively large region of the world.

Abstract Endometriosis (EMS) is a multifactorial disease that affects 10%–15% women of reproductive age and is associated with chronic pelvic pain and infertility. The pathogenesis of EMS has not been consistently explained until now. In this study, we involved 36 endometriosis patients and 14 control subjects who performed laparoscopic surgery due to gynecological benign tumor. The samples from lower third of vagina (CL), posterior vaginal fornix (CU), cervical mucus (CV), endometrium (ET) and peritoneal fluid (PF), were collected and sequenced by 16S rRNA amplicon. The continuous change of the microbiota distribution was identified along the reproductive tract. The flora in lower reproductive tract (CL, CU) were dominated by Lactobacillus. Significant difference of the community diversity began showing in the CV of EMS patients and gradually increased upward the reproductive tract. It indicates the microbiota in cervical samples is expected to be an indicator for the risk of EMS. This study also highlights the decreasing of Lactobacillus in vaginal flora and the increasing of signature Operational Taxonomic Units (OTUs) in transaction zone (CV) and upper reproductive tract (ET, PF) of EMS patients, which reflect the alteration of microbial community associated with EMS, participation of specific colonized bacteria in the EMS pathogenesis and relationship between microbiota and development of disease.

Cell phones are an essential device for today’s people. The warm environment on the cell phone may cause continuous growth of bacteria which can include harmful pathogens. This research aimed to determine if there is a relationship between gender and the daily routine environment with the bacteria count on the cell phone. The data were analysed using the chi-square test and the results showed no relationship (P>0.05). In addition, a survey questionnaire was conducted to study the common habits that are conducive to a microbial distribution pattern on a cell phone. Some of the common habits were using the cell phones while in the washroom and improper cell phone cleaning methods. The behavior of using the cell phone while dining and the microbial distribution pattern were found to be independent. This study aimed to provide awareness on the importance of keeping cell phones clean to minimize microbial contamination.

The damaging competition between crops and parasitic weeds has a negative impact on agricultural productivity; however, the impact of disturbance on the soil’s microbial community has received less attention. Hence, this study investigates the microbial composition and diversity of the maize rhizosphere infected with Striga hermonthica using a shotgun sequencing approach from two maize-growing fields (Eruwa, Nigeria and Mbuzini, South Africa). The rhizosphere soil DNA was extracted from infested soil using a Nucleospin soil genomic DNA extraction kit and sequenced on an Illumina platform. The dominant phyla were Actinobacteria, Bacteroidetes, Deinococcus-Thermus, Acidobacteria, Chloroflexi, Cyanobacteria, Planctomycetes, Verrucomicrobia, Chlorobi, Proteobacteria, Firmicutes, Nitrospirae, Thermotogae, Synergistetes, Ascomycota, Euryarchaeota, and Crenarchaeota. Bacteria phyla were observed to be of higher proportion in the rhizosphere soil samples obtained from Striga-infested maize field in Eruwa (Es) than those recovered from Mbuzini (Ms). The alpha diversity of microbial communities indicated insignificance differences (p > 0.05) between the five taxonomical groups (phylum, class, order, family, and genus), while the beta diversity produced a significant (p = 0.01, R = 0.52) difference in the microbial diversity of the infested soil. In summary, the study sheds light on the diversity and composition of the microbiome of Striga hermonthica-infested soil, which influences the microbial functions in the management and sustenance of plant health against parasitic weeds.

The large number of dormant microorganisms present in the environment is an important component of microbial diversity, and neglecting dormant microorganisms would be disruptive to all research under the science of microbial diversity. However, current methods can only predict the dormancy potential of microorganisms in a sample and are not yet able to monitor dormant microorganisms directly and efficiently. Based on this, this study proposes a new method for the identification of dormant microorganisms based on high-throughput sequencing technology: Revived Amplicon sequence variants (ASV) Monitoring (RAM). Pao cai (Chinese fermented vegetables) soup was used to construct a closed experimental system, and sequenced samples were collected at 26 timepoints over a 60-day period. RAM was used to identify dormant microorganisms in the samples. The results were then compared with the results of the currently used gene function prediction (GFP), and it was found that RAM was able to identify more dormant microorganisms. In 60 days, GFP monitored 5045 ASVs and 270 genera, while RAM monitored 27,415 ASVs and 616 genera, and the RAM results were fully inclusive of the GFP results. Meanwhile, the consistency of GFP and RAM was also found in the results. The dormant microorganisms monitored by both showed a four-stage distribution pattern over a 60-day period, with significant differences in the community structure between the stages. Therefore, RAM monitoring of dormant microorganisms is effective and feasible. It is worth noting that the results of GFP and RAM can complement and refer to each other. In the future, the results obtained from RAM can be used as a database to extend and improve the monitoring of dormant microorganisms by GFP, and the two can be combined with each other to build a dormant microorganism detection system.

[Display omitted] • Biofilms grown at different polyurethane carrier depths were layered. • Three distinct stages of biofilm development were studied. • Measurements and modeling were performed at various carrier depths. • AOB, AnAOB, and denitrifiers were mostly in the outer, middle, and inner layers. In this study, matrix degradation, microbial community development, and distribution using an individual-based model during biofilm formation on carriers at varying depths within a single-stage partial nitrification/anammox system were simulated. The findings from the application of individual-based model fitting, fluorescence in situ hybridization, and high-throughput sequencing reveal the presence of aerobic bacteria, specifically ammonia-oxidizing bacteria, as discrete particles within the outer layer of the carrier. Facultative anaerobic bacteria exemplified by anaerobic ammonia-oxidizing bacteria, are observed as aggregates within the middle layer. Conversely, anaerobic bacteria, represented by denitrifiers, are enveloped by extracellular polymeric substances within the inner layer. The present study extends the application of individual-based model to the formation of polyurethane-supported biofilms and presents valuable avenues for the design and advancement of pragmatic engineering carriers. [ABSTRACT FROM AUTHOR]

Co-fermentation of sewage sludge and algae was performed for enhancing the hydrogen production, and the effect of Fe2+ on co-fermentation process was examined. Results showed that both co-fermentation process and Fe2+ addition promoted hydrogen production. Highest hydrogen production of 28 mL/100 mL (14.8 mL H 2 /g VS added) was obtained from the co-fermentation group with 600 mg/L Fe2+ addition, which was 2.15 times, 2.00 times and 1.87 times of mono-fermentation of sludge, mono-fermentation of algae, and the co-fermentation group without Fe2+ addition. Both volatile solids and protein degradation were stimulated by co-fermentation process. Microbial analysis showed that co-fermentation groups with Fe2+ addition enriched Clostridium sensu stricto 13, Clostridium tertium and Terrisporobacter , which were positively correlated with cumulative hydrogen production. This study suggested that the co-fermentation of sludge and algae in the presence of Fe2+ could significantly improve the hydrogen production by stimulating the hydrogen-producing metabolism. Image 1 • Co-fermentation of sewage sludge and algae was performed for H 2 production. • Fe2+ addition promoted the substrate utilization and H 2 production. • H 2 production was positively related with soluble organics and Fe2+ in substrate. • Fe2+ addition enriched Clostridium sp. which was favorable for H 2 production. [ABSTRACT FROM AUTHOR]

A total of 68 315 digitised records of myxomycetes from the eastern United States were compiled from all readily available sources. After cleaning the database for inconsistencies, 58 594 records remained that were suitable for analysis. A total of 460 different species of myxomycetes were recorded, out of which 410 were classified as rare. Five species were represented by more than 1 500 records and 44 species were represented by only a single record. The states of New York, Virginia and West Virginia have the highest number of records. Almost half of the recognised morphospecies of myxomycetes in the world occur in the eastern United States. A small number of species thrive in different ecological conditions, whereas most species require more specific ecological settings for the formation of fruiting bodies. States associated with high biodiversity have been subjected to more intensive sampling efforts, and southern states seem to have been less studied than northern ones. The project described herein apparently represents one of the few efforts to characterise the myxobiota of a relatively large region of the world. [ABSTRACT FROM AUTHOR]

Endometriosis (EMS) is a multifactorial disease that affects 10%–15% women of reproductive age and is associated with chronic pelvic pain and infertility. The pathogenesis of EMS has not been consistently explained until now. In this study, we involved 36 endometriosis patients and 14 control subjects who performed laparoscopic surgery due to gynecological benign tumor. The samples from lower third of vagina (CL), posterior vaginal fornix (CU), cervical mucus (CV), endometrium (ET) and peritoneal fluid (PF), were collected and sequenced by 16S rRNA amplicon. The continuous change of the microbiota distribution was identified along the reproductive tract. The flora in lower reproductive tract (CL, CU) were dominated by Lactobacillus. Significant difference of the community diversity began showing in the CV of EMS patients and gradually increased upward the reproductive tract. It indicates the microbiota in cervical samples is expected to be an indicator for the risk of EMS. This study also highlights the decreasing of Lactobacillus in vaginal flora and the increasing of signature Operational Taxonomic Units (OTUs) in transaction zone (CV) and upper reproductive tract (ET, PF) of EMS patients, which reflect the alteration of microbial community associated with EMS, participation of specific colonized bacteria in the EMS pathogenesis and relationship between microbiota and development of disease. [ABSTRACT FROM AUTHOR]

Streambank legacy sediments may be important sources of sediment and nutrients from Mid-Atlantic watersheds. However, little is known about the nutrient processing roles of microorganisms that inhabit legacy sediments, let alone their composition, diversity, and distributions. In this study, we sampled 15 streambanks at multiple depths throughout four watersheds in the Mid-Atlantic Region of the USA. High throughput sequencing of 16S ribosomal RNA genes indicated that streambank microbial community composition varied within site depth and across contemporary land uses. Collectively, the most abundant microbial taxa in legacy sediments included Acidobacteria (25–45%), Proteobacteria (15–40%), Nitrospirae (2–10%), Chloroflexi (1–5%), and Actinobacteria (1–10%). Bacterial community composition was distinct between agriculture and urban sites as well as suburban and urban sites. There was significant variation in community composition between the top (1–25%), upper-middle (26–50%), and bottom layers (76–100%) of sediments, while the relative abundances differed between layers for only Acidobacteria and Proteobacteria. Several streambank chemistry variables (metals, %TC, and %TN) had weak positive correlations with community composition. Compared to ammonia-oxidizing bacteria, nitrifying archaea were more predominant. This study provides the first insights into detailed microbial composition of legacy sediments and identifies environmental drivers for community structure and nitrogen processing. Future studies should consider exploring the role of this unique microbial environment for nutrient processing and leaching from legacy sediments and its implications for watershed water quality. [ABSTRACT FROM AUTHOR]

Cell phones are an essential device for today's people. The warm environment on the cell phone may cause continuous growth of bacteria which can include harmful pathogens. This research aimed to determine if there is a relationship between gender and the daily routine environment with the bacteria count on the cell phone. The data were analysed using the chi-square test and the results showed no relationship (P>0.05). In addition, a survey questionnaire was conducted to study the common habits that are conducive to a microbial distribution pattern on a cell phone. Some of the common habits were using the cell phones while in the washroom and improper cell phone cleaning methods. The behavior of using the cell phone while dining and the microbial distribution pattern were found to be independent. This study aimed to provide awareness on the importance of keeping cell phones clean to minimize microbial contamination. [ABSTRACT FROM AUTHOR]

Biodrying of dewatered sludge is an eco-friendly and efficient technology to decrease the sludge moisture content (MC) by metabolic heat generated from sludge organic matter degradation. By analyzing the water states and visualizing the sludge pore structure during the biodrying process, it was found that the bound water accounted for 96.5–97.9% of the sludge water and interstitial water was only 2.0–3.5%. The microscopic and dispersed sludge pores were transformed into larger and linked ones by the transformation of bound water into interstitial water and the subsequent evaporation. As a result, the depth of live bacteria distribution thickened, reaching 0–180 µm, 0–330 µm, and 0–350 µm during the temperature ramp-up to 45.6 °C, the peak temperature of 70.7 °C, and the cool-down to 45.6 °C, respectively. Briefly, as moisture evaporated, the pore structure of the sludge expanded and the microbial distribution deepened. Moreover, the phylum of anaerobic bacteria was drastically decreased. [Display omitted] • Bound water accounted for 96.5%−98.0%. • Pores became connected. • Live bacteria grew towards sludge interion. • Anaerobic phylum reduced in biodrying. • Water states and VS had significant effect on microbial community. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Fe0 nanoparticles (Fe0 NPs) could improve H 2 production from macroalga. • Hydrogen production was enhanced by 6.5 times comparing to control test. • Fe0 NPs promoted hydrogen production and acid accumulation. • Fe0 NPs enriched Clostridium and Terrisporobacter sp. Abstract In this work, effect of Fe0 nanoparticles (Fe0 NPs) on macroalgae fermentation was explored. Hydrogen production was significantly enhanced by 6.5 times comparing with control test, achieving 20.25 mL H 2 /g VS added with addition of 200 mg/L Fe0 NPs. In-depth analysis of substrate conversion showed that both hydrogen generation and acids accumulation were promoted with Fe0 NPs supplementation. Microbial analysis demonstrated that both hydrogen-producing strains belonging to genus Clostridium and Terrisporobacter sp. favorable for acids formation were enriched with Fe0 NPs supplementation, while species Acinetobacter lwoffii beneficial to organics mineralization was eliminated. Complex substrate compositions resulted in more prevalent cooperative relationships among species in the system. This study suggested that Fe0 NPs plays a crucial role in macroalgae fermentation by affecting the microbial distribution, subsequently influencing the products distribution and energy conversion. [ABSTRACT FROM AUTHOR]

Low-impact development (LID) techniques are being applied to reduce non-point source (NPS) pollution which are generated from various land uses. Cost-effective LID design requires consideration of influent runoff properties as well as physical and ecological pollutant-removing mechanisms. However, current LID technology design has failed to reflect the different properties of influent water from various land uses, and the biological design factors in LID facilities causing low efficiency and difficulties in maintenance. This study was conducted to identify biological design factors by analyzing the impact of the pollutants included in influent runoff and physical environment on microbial growth in rain garden facilities applied to different land uses. The results showed that the non-point source pollutant loadings were about 1.5–3 times higher in the runoff from parking lots, which are frequently visited by automobiles than in roof runoff. Type of soil, chemical species, and chemical composition were assessed as internal environmental factors having significant impact on the phylum and the count of microorganisms in the facilities. The growth of Cyanobacteria, Streptophyta, Chlorophyta, Bacillariophyta, and Xanthophyceae was good when there was appropriate water content in the soil, light, and sandy soil. Based on these results, the future design of rain garden facilities should be performed by considering a microorganism appropriate to the properties of the influent pollutants, determining appropriate water content, nutrient content and soil type, and choosing plants that contribute to microbial growth. [ABSTRACT FROM AUTHOR]

[Display omitted] • EPDA granules were successfully cultured, and enhanced in situ enrichment of AnAOB. • AnAOB could harmoniously coexist with GAOs and PAOs in granules, and resided in the inner layer. • Advanced nitrogen and phosphorus removal was achieved in the EPDA granular system. • Anammox-related key functional genes had higher activity at the transcriptome level. The direct application of anammox to wastewater treatment is valuable, but the enrichment of anammox bacteria (AnAOB) is complicated due to the malignant competition of heterotrophic bacteria. Here, we propose the use of endogenous partial denitrification/anammox (EPDA) granular sludge to enhance anammox while achieving simultaneous removals of nitrogen and phosphorus. After operation for 330 days, the EPDA granules were successfully cultured with the mean size of 0.89 mm. Nitrogen and phosphorus were efficiently removed with the effluent total nitrogen (TN) and PO 4 3--P of 6.68±0.41 mg/L and 0.06±0.03 mg/L, respectively. Anammox took a leading role in the removal of TN with a contribution of 75±3%. Moreover, high-throughput sequencing (16S rRNA) results showed that AnAOB could coexist harmoniously with glycogen accumulating organisms (GAOs) and polyphosphate accumulating organisms (PAOs) in the EPDA granules, whereas mature EPDA granules could promote in situ enrichment of AnAOB. Microbial stratification analysis of the EPDA granule found that the inner layer was resided with AnAOB, while the outer layer was employed with GAOs and PAOs. Metagenomic and metatranscriptomic analyses found that the nitrate reductase (1150.56 RPM) was 4.6 times of nitrite reductase (249.98 RPM) at the transcriptome level. Moreover, the key enzymes related to anammox (hydrazine synthase and hydrazine dehydrogenase) were much higher than the other nitrogen conversion functional genes at the transcriptome level, confirming the main role of AnAOB in the removal of nitrogen. This study presents a novel strategy for the application of anammox from EPDA granular sludge. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antibiotic fermentation residues (AFRs) could be used for MCFAs production. • The fate of antibiotic resistance genes (ARGs) during fermentation was explored. • The chain elongation (CE) microorganisms could inhibit ARGs amplification. • The potential of gene horizontal transfer of ARGs increased during fermentation. • Two-stage anaerobic fermentation could effectively restrict the ARGs amplification. The potential of antibiotic resistance genes (ARGs) amplification restricts the biological recovery of antibiotic fermentation residues (AFRs) through two-stage anaerobic fermentation. This study explored the fate of ARGs during the fermentation of AFRs that comprising of acidification and chain elongation (CE). Results showed that with the alteration of fermentation process from acidification to CE, microbial richness was significantly increased, total abundance of ARGs was slightly decreased by 1.84%, and the significant negative correlations between ARGs and microbes were increased, implied the inhibitory effect of CE microbes to ARGs amplification. However, the total abundance of mobile genetic elements (MGEs) was increased by 24.5%, indicating that the potential of gene horizontal transfer of ARGs increased. This work suggested that two-stage anaerobic fermentation could effectively restrict the ARGs amplification, but more concerns are needed for the long-term dissemination of ARGs. [ABSTRACT FROM AUTHOR]

In this study, effects of porous carrier's size (polyurethane-based) on microbial characteristics were systematically investigated in addition to nitrogen removal performance in six microaerobic bioreactors. Among different sized carriers (50, 30, 20, 15,10, 5 mm), 15 mm carrier showed highest nitrogen removal (98%) due to optimal micro-environments created for aerobic nitrifiers in outer layer (0-7 mm), nitrifiers and denitrifiers in middle layer (7-10 mm) and anaerobic denitrifiers in inner layer (10-15 mm). Candidatus brocadia, a dominant anammox bacteria, was solely concentrated close to centroid (0-70 μm) and strongly co-aggregated with other bacterial communities in the middle layer of the carrier. Contrarily, carriers with a smaller (<15 mm) or larger size (>15 mm) either destroy the effective zone for anaerobic denitrifiers or damage the microaerobic environments due to poor mass transfer. This study is of particular use for optimal design of carriers in enhancing simultaneous nitrification-denitrification in microaerobic wastewater treatment processes. [ABSTRACT FROM AUTHOR]

Aiming for treating decentralized domestic wastewater in rural China, this study evaluates the effects of ceramsite size and structure, and water recirculation parameters, upon the performance of recirculating biofilter (RBF). RBF shows stable capability of chemical oxygen demand (COD) remediation and ammonia nitrification. In addition, the microbial flora and structures of the various layers in the system are analyzed via high-throughput sequencing in order to study the microbial diversity. The results indicate that while the ceramic particle size has no significant influence on the COD remediation capacity, the ceramics with smaller particle sizes exhibit better ammonia nitrogen (NH 4 +-N) removal ability, with a first-order linear relationship between the influent ammonia nitrogen load and the effluent NH 4 +-N concentration in RBF (R2 > 0.64). An increased hydraulic load and intermittent operation are shown to deteriorate the water quality with respect to NH 4 +-N, while an increased recirculation ratio increases the removal rate of NH 4 +-N from the effluent. Further, the water distribution time has a stronger effect upon the NH 4 +-N concentration in the effluent than does the recirculation ratio. Moreover, the microbial structure of the multi-layer recirculating trickle biofilter varies significantly during the process. The results indicate that a high recirculation ratio, long water distribution time, and multi-layer structure will be beneficial for improving the pollutant treatment capacity of RBF. • Ceramics with smaller sizes exhibit better ammonia nitrogen removal ability. • Influent NH 4 +-N load first-order linear related effluent NH 4 +-N concentration. • Water distribution time strongly effects the effluent NH 4 +-N concentration. • Multi-layer structure effectively differentiated microbial community structure. [ABSTRACT FROM AUTHOR]

The redistribution of soil and associated organic matter across landscape represents a major perturbation to the carbon cycle because the established colluvial soils change the levels of C mineralization and sequestration. In this study, two profiles of a colluvial soil 4 m deep were analyzed to test whether its two layers produced by erosion differ from the organic layer of the original soil and if the microbial characteristics correspond to the soil properties. The structure of microbial communities was assessed by both quantitative PCR and Illumina amplicon sequencing. Microbial activities were determined by hydrolytical enzymes. The bacterial community structure was correlated with vertical gradients of soil chemical properties. The dominating bacterial phyla were the same along the whole profile but their relative abundance changed. The upper horizon determined by tillage and reaching to approx. 75 cm had highest values of dissolved organic carbon, P and K and was characterized by Proteobacteria and Bacteroidetes . Also, the activities of hydrolytical enzymes occurred mostly there. The second horizon of deposited soil reaching to approx. 250 cm was characterized by Acidobacteria and Gemmatimonadetes . The lowest horizon of buried Chernozem was characterized by increased soil organic carbon, manganese, iron and sulfate and characterized by Nitrospirae and Rubrobacteria . The community analysis indicated that chemolithotrophic processes might be important in these buried horizons so the decomposition may be slower and residence times for these deep carbon pools longer than in the original upper horizons. In these colluvial systems, erosion could lead to soil organic C stabilization. [ABSTRACT FROM AUTHOR]

Hydrothermal plumes are widely distributed throughout the global spreading ridges, yet few of them are microbiologically explored. The ultraslow-spreading ridges, recently recognized as a unique, new class of mid-ocean-ridge system, have provided surprises and new insights in hydrothermal system research. A suite of water column samples including both hydrothermal plume samples and ambient seawater were collected at different depths from the ultraslow-spreading Southwest Indian Ridge (SWIR) in 2010. We use molecular approaches such as clone libraries, denaturing gradient gel electrophoresis (DGGE) and quantitative PCR to determine microbial community compositions and their spatial variability within the hydrothermal plume and seawater. Phylogenetic analysis showed that plume samples were mainly dominated by members ofα-Proteobacteriaandγ-Proteobacteriaand members of marine group I group within theCrenarchaeota. Within the hydrothermal plume, archaeal populations were spatially homogeneous, while bacterial compositions were heterogeneous and remarkably distinct at different depths. Moreover, several lineages, closely related to known Mn(II) oxidizers were found to be abundant and even predominant within the plume bacterial communities. DGGE band patterns showed that there was no significant difference in microbial compositions between the samples of hydrothermal plume and ambient seawater. Taken together, we inferred that microbial communities in the SWIR hydrothermal plumes were sourced from ambient seawater rather than from seafloor vent-derived niches. This is the first report on the characteristics of microbial community structures in hydrothermal plume and ambient seawater in the Southwest Indian Ridge. [ABSTRACT FROM PUBLISHER]

In this study, a risk assessment of proteolytic Clostridium botulinum in canned foie gras was performed, the number of illnesses per year in France due to C. botulinum in foie gras was estimated. Data on initial level in raw materials were collected at manufacturers and analysed using a Negative Binomial distribution. The effect of the usual foie gras heat treatment (equivalent time at 121 °C: F 0 = 0.5 min) was considered at two levels: first, it led to an inactivation (estimated to 2.3 log); second it led to a spore injury and then to a spore inhibition. This latter effect was assessed by analysing data from a challenge test study carried out with Clostridium sporogenes spores in the foie gras product. The probability of spore recovering after thermal inhibition was estimated to 9.5 × 10 − 8 (corresponding to 7.0 log). The data on the consumption pattern were collected on the French market. The Quantitative Microbiological Risk Assessment (QMRA) model and all the assumptions are reported in detail in the study. The initial contamination of raw materials, effect of thermal treatment on microbial inactivation and spore inhibition were handled mathematically using a probabilistic framework, considering only the variability dimension. The model was implemented in Excel and run through Monte Carlo simulation, using @Risk software. In parallel, epidemiological data collected from the French Institute for Public Health Surveillance during the period 2001–2012 were used to estimate an Appropriate Level Of Protection (ALOP) and then a Food Safety Objective (FSO): ALOP equalled to 2.5 × 10 − 3 illnesses per million inhabitant per year, FSO equalled to 1.4 × 10 − 9 foie gras portions containing C. botulinum spore (expressed in decimal logarithm, FSO = − 8.9). The QMRA model output values were smaller, but on the same order of magnitude as these two figures: 8.0 × 10 − 4 illnesses per million inhabitants per year, and, 4.5 × 10 − 10 (− 9.3 log) foie gras portions containing C. botulinum spores able to recover. It was then possible to conclude that the current practices regarding thermal treatment of canned foie gras are sufficient to control the risk of C. botulinum in foie gras in France. [ABSTRACT FROM AUTHOR]

• Quantitative light-induced fluorescence used to evaluate caries activity in primary molars. • Red fluorescence measures are associated with caries activity. • Microbial factors may be important in predicting the activity of carious lesions. • The levels of Lactobacillus species in carious dentin, and levels of S. sobrinus in saliva are associated with caries lesion activity status. This study aimed to assess differences in quantitative measures obtained from the quantitative light-induced fluorescence method and microbial composition of carious dentin and saliva according to the activity status of caries lesions in primary molars. A total of 34 teeth from 34 children were evaluated in this study. The activity status of carious lesions was classified using the International Caries Classification and Management System criteria (active or inactive). Images of the carious lesions were captured using a quantitative light-induced fluorescence device for quantitative analyses. Carious dentin and saliva were collected to detect and quantify selected bacterial species (S. mutans, S. sobrinus, Lactobacillus species , F. nucleatum, P. nigrescence, P. intermedia) and C. albicans by quantitative polymerase chain reaction. Mann–Whitney U tests were performed to evaluate differences in quantitative measures from quantitative light-induced fluorescence, the microbial composition of carious dentin, and saliva according to the activity status of carious lesions. Red fluorescence values (∆R, ∆Rmax) from the quantitative light-induced fluorescence method were significantly higher in active lesions (∆R, p = 0.009; ∆Rmax, p = 0.014). The quantitative mean levels of Lactobacillus species (p = 0.010) in carious dentin and S. sobrinus (p = 0.017) in saliva were significantly higher in the active-lesion group. Quantitative measures related to red fluorescence from the quantitative light-induced fluorescence method, levels of Lactobacillus species from carious dentin, and levels of S. sobrinus from saliva were associated with caries lesion activity. [ABSTRACT FROM AUTHOR]

A species Schizoblastosporion starkeyi-henricii is common in peats and peaty soils. Fifteen strains of this species isolated from Europe and East Falkland Island were found homogenous in cultural, morphological and physiological characters, with the exception of one strain that was sensitive to elevated osmotic pressure. Analyses of the D1/D2 region of the 26S rDNA and internal transcribed spacers (ITS) confirm that these strains and also Asian isolates are conspecific. Our results show that ecological factors but not geographic distances determine the global distribution of yeast fungi. [ABSTRACT FROM AUTHOR]

Single-stage nitritation-anammox combines the growth of aerobic ammonium-oxidizing bacteria (AOB) and anaerobic ammonium oxidizing bacteria (AnAOB) in one reactor. The necessary compromise of their milieu conditions often leads to the growth of nitrite-oxidizing bacteria (NOB). For this study, a sequencing batch reactor (SBR) for nitritation-anammox was operated for 180 days with sewage sludge reject water (removal capacity, 0.4 kg N m day). The growth of NOB was favored by enhanced oxygen supply rather than extended aerobic phases. Suspended-type biomass from this SBR was taken regularly and sieved into three size fractions (all of them <1,000 μm). Batch experiments as well as fluorescence in situ hybridization were performed to study the distribution and activity of AnAOB, AOB, and NOB within those size fractions. Both the measured conversion rates and detected abundances decreased with increasing size fraction. The highest anammox conversion rates (15 g NH-N per kilogram VSS per hour) and the highest abundances of Brocadia fulgida were found in the medium size fraction (100-315 μm). The batch experiments proved to be accurate tools for the monitoring of multiple processes in the reactor. The results were representative for reactor performance during the 6 months of reactor operation. [ABSTRACT FROM AUTHOR]

The toxicity of trichloroethene ( TCE) likely restricts microbial activity in close vicinity of a TCE dense nonaqueous phase liquid ( DNAPL). This study examined the distribution of a dechlorinating community in relation to the distance from a TCE DNAPL using a diffusion-cell set-up. Subcultures of the KB-1™ culture dechlorinating TCE to cis-dichloroethene and grown with either formate or lactate as electron donor were used to inoculate the diffusion-cells. 16 S rRNA gene clone library analysis showed that both inocula consisted of dechlorinating bacteria similar to Geobacter lovleyi SZ and fermentative microorganisms related to Clostridium and Clostridiales. qPCR and RFLP analyses of pore water and sand samples showed a stratified microbial community composition in the diffusion-cells. Geobacter dominated where TCE was present, that is, in the lower 3 cm of the 5.5-cm-thick sand layer. Even at 0.5 cm distance from the DNAPL layer, Geobacter densities were two orders of magnitude higher than at inoculation, despite the expected TCE toxicity. In the upper 2.5 cm of the sand layer, where TCE was depleted, apparently fermenting populations prevailed, corresponding to Clostridium in some diffusion-cells. This analysis demonstrates that the microbial community composition in a source zone is related to the distance from the DNAPL. [ABSTRACT FROM AUTHOR]

Abstract: Self-made sludge-ceramsite was tested as carrier in biofilter to investigate its biogenic stimulating properties for obtaining high biomass concentration, and the performance of Guangzhou ceramsite, Jiangxi ceramsite, and Shanxi activated carbon were provided as a baseline for comparison. Results show that the removal efficiencies of COD and total nitrogen (TN) increase along with the increased COD/NH4 +–N ratio (4, 5.7, 8, and 10) in the four biofilters. On average, the sludge-ceramsite biofilter converts 79.1–86.4% of NH4 +−N to NOx −−N and removes 43.9–51.0% of TN at COD/NH4 +–N ratios of 4–10, which are slightly better than the other biofilters. The well-developed porous structures (0.5μm

Abstract: Two-stage upflow anaerobic sludge blanket (UASB) process was investigated as an efficient process configuration option for the treatment of purified terephthalic acid (PTA) wastewater. To study its feasibility in a defined condition, synthetic wastewater containing only the major pollutants (i.e., acetate, benzoate, terephthalate and p-toluate) was used. By focusing the role of the second stage on the p-toluate degradation, improved overall COD and p-toluate removal capacities of 4.18 and 1.35 g-thCOD/L·day could be achieved together with a complete COD removal efficiency. In this situation, all the pollutants except p-toluate were completely degraded in the first stage while 38 and 62% of p-toluate originally present in the wastewater were consecutively degraded in the individual stages. The concomitant methane production rate in each stage was 0.91 and 0.35 L/L·day respectively, and the methane yield on p-toluate was determined to be 0.12 L/g-thCOD. Batch tests using the granules obtained from each stage revealed that the acidogenic microorganisms enriched in both stages had a universal ability to degrade all aromatic pollutants present in the PTA wastewater. Moreover, image analysis using scanning electron microscope and confocal laser scanning microscopy combined with fluorescence in situ hybridization technique elucidated that the distribution of acidogens and methanogens within the granule was varied in each stage, which influenced the mass transfer regime resulting in the different pollutant degradation rates during the batch tests. [Copyright &y& Elsevier]

Efficient nitrification and denitrification of wastewater containing 1,700 mgl−1 of ammonium-nitrogen was achieved using aerobic granular sludge cultivated at medium-to-high organic loading rates. The cultivated granules were tested in a sequencing batch reactor (SBR) fed with 6.4 or 10.2 kg NH-N m−3 day−1, a loading significantly higher than that reported in literature. With alternating 2 h oxic and 2 h anoxic operation (OA) modes, removal rate was 45.5 mg NH-N g−1 volatile suspended solids−1 h−1 at 6.4 kg NH-N m−3 day−1 loading and 41.3 ± 2.0 at 10.2 kg NH-N m−3 day−1 loading. Following the 60 days SBR test, granules were intact. The fluorescence in situ hybridization and confocal laser scanning microscopy results indicate that the SBR-OA granules have a distribution with nitrifers outside and heterotrophs outside that can effectively expose functional strains to surrounding substrates at high concentrations with minimal mass transfer limit. This microbial alignment combined with the smooth granule surface achieved nitrification–denitrification of wastewaters containing high-strength ammonium using aerobic granules. Conversely, the SBR continuous aeration mode yielded a distribution with nitrifers outside and heterotrophs inside with an unsatisfactory denitrification rate and floating granules as gas likely accumulated deep in the granules. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biofouling formation mechanism in MD for desulfurization wastewater were revealed. • Pioneering bacteria was identified and microbial succession process was discussed. • Microbial function and its effect on DOM and microbial variation was interpreted. • Heat- and salinity-stress driven the reconstruction of microbial community. • CP, flow-, heat-, nutrient-stress were responsible for the spatial distribution. The unrevealed mystery of biofouling obfuscates the understanding of fouling mechanism and the commercial application of Membrane distillation (MD). In this study, biofouling was revealed with respect to microbial morphology, distribution, succession, and function in MD for desulfurization wastewater. Heat- and salinity-stress driven the reconstruction of microbial community with a decrease in diversity, activity, and motility. Idiomarina and Phenylobacterium were enriched on membrane for higher cell motility and degradation ability. Horizontal distribution appeared with rising fouling tendency and longer but thinner cells, result from the Concentration polarization (CP), heat-, flow-, and nutrient-stress. Vertically, bacteria with higher motility, secretory ability, and activity like Chelativorans , Acinetobater , Salinarimonas attached to membrane surface firstly. Then pioneering bacteria with low microbial biosynthesis and cellular process but high degradation ability accumulated in the bottom layer, driven the DOM transformation for higher tryptophan and tyrosine metabolism. CP was a key reason for the accumulation of upper layer, in where the bacteria had low cellular process and motility. This work reveals the microbial succession and biofouling formation process, which provides an in-depth information to fill the knowledge gap of MD biofouling. [ABSTRACT FROM AUTHOR]

Three identical upflow laboratory-scale biofilters, inoculated with the benzene-degrading strain Pseudomonas sp. NCIMB 9688 but filled up with different packing media (PM), specifically raw sugarcane bagasse, sieved sugarcane bagasse and peat, were employed to eliminate benzene from waste air. Biofilters performances were evaluated by continuous runs in parallel at different influent benzene concentrations, sequentially stepped up through three different superficial gas velocities (31, 61, and 122 m h-1). The peat-packed biofilter exhibited the best performances over the whole experimentation, ensuring removal efficiency of 100% for influent benzene concentrations ≤0.05 g m-3, regardless of the superficial gas velocity, and up to 0.4 g m-3 at 31 m h-1. Maximum elimination capacities of biofilters packed with raw and sieved sugarcane bagasse and with peat were 3.2, 6.4 and 26 g mPM-3 h-1 at 6.1, 12 and 31 g mPM-3 h-1 loading rates, resulting in 52, 53 and 84% removals, respectively. The bacterial concentration distribution along the medium was shown to depend on the benzene loading rate and a correlation between specific benzene elimination rate and biomass concentration was established for biofilters packed with sieved sugarcane bagasse and peat. The macrokinetics of the process were also studied using the profiles of benzene and biomass concentrations, collected under different conditions over the height of both biofilters, and a zeroth-order kinetic model was shown to describe successfully the degradation process. [ABSTRACT FROM AUTHOR]