Shifts in structure and dynamics of the soil microbiome in biofuel/fuel blend-affected areas triggered by different bioremediation treatments.

The use of biofuels has grown in the last decades as a consequence of the direct environmental impacts of fossil fuel use. Elucidating structure, diversity, species interactions, and assembly mechanisms of microbiomes is crucial for understanding the influence of environmental disturbances. However, little is known about how contamination with biofuel/petrofuel blends alters the soil microbiome. Here, we studied the dynamics in the soil microbiome structure and composition of four field areas under long-term contamination with biofuel/fossil fuel blends (ethanol 10% and gasoline 90%-E10; ethanol 25% and gasoline 75%-E25; soybean biodiesel 20% and diesel 80%-B20) submitted to different bioremediation treatments along a temporal gradient. Soil microbiomes from biodiesel-polluted areas exhibited higher richness and diversity index values and more complex microbial communities than ethanol-polluted areas. Additionally, monitored natural attenuation B20-polluted areas were less affected by perturbations caused by bioremediation treatments. As a consequence, once biostimulation was applied, the degradation was slower compared with areas previously actively treated. In soils with low diversity and richness, the impact of bioremediation treatments on the microbiomes was greater, and as a result, the hydrocarbon degradation extent was higher. The network analysis showed that all abundant keystone taxa corresponded to well-known degraders, suggesting that the abundant species are core targets for biostimulation in soil remediation processes. Altogether, these findings showed that the knowledge gained through the study of microbiomes in contaminated areas may help design and conduct optimized bioremediation approaches, paving the way for future rationalized and efficient pollutant mitigation strategies.

Fungal Screening for Potential PET Depolymerization.

Approximately 400 billion PET bottles are produced annually in the world, of which from 8 to 9 million tons are discarded in oceans. This requires developing strategies to urgently recycle them. PET recycling can be carried out using the microbial hydrolysis of polymers when monomers and oligomers are released. Exploring the metabolic activity of fungi is an environmentally friendly way to treat harmful polymeric waste and obtain the production of monomers. The present study addressed: (i) the investigation of potential of strains with the potential for the depolymerization of PET bottles from different manufacturers (crystallinity of 35.5 and 10.4%); (ii) the search for a culture medium that favors the depolymerization process; and (iii) gaining more knowledge on fungal enzymes that can be applied to PET recycling. Four strains (from 100 fungal strains) were found as promising for conversion into terephthalic acid from PET nanoparticles (npPET): Curvularia trifolii CBMAI 2111, Trichoderma sp. CBMAI 2071, Trichoderma atroviride CBMAI 2073, and Cladosporium cladosporioides CBMAI 2075. The fermentation assays in the presence of PET led to the release of terephthalic acid in concentrations above 12 ppm. Biodegradation was also confirmed using mass variation analyses (reducing mass), scanning electron microscopy (SEM) that showed evidence of material roughness, FTIR analysis that showed band modification, enzymatic activities detected for lipase, and esterase and cutinase, confirmed by monomers/oligomers quantification using high performance liquid chromatography (HPLC-UV). Based on the microbial strains PET depolymerization, the results are promising for the exploration of the selected microbial strain.

Two problems in one shot: Vinasse and glycerol co-digestion in a thermophilic high-rate reactor to improve process stability even at high sulfate concentrations.

Anaerobic co-digestion (AcoD) of sugarcane vinasse and glycerol can be profitable because of the destination of two biofuel wastes produced in large quantities in Brazil (ethanol and biodiesel, respectively) and the complementary properties of these substrates. Thus, the objective of this study was to assess the effect of increasing the organic loading rate (OLR) from 2 to 20 kg COD m-3 d-1 on the AcoD of vinasse and glycerol (50 %:50 % on a COD basis) in a thermophilic (55 °C) anaerobic fluidized bed reactor (AFBR). The highest methane production rate was observed at 20 kg COD m-3 d-1 (8.83 L CH4 d-1 L-1), while the methane yield remained stable at around 265 NmL CH4 g-1 CODrem in all conditions, even when influent vinasse reached 1811 mg SO42- L-1 (10 kg COD m-3 d-1). Sulfate was not detected in the effluent. Bacterial genera related to sulfate removal, such as Desulfovibrio and Desulfomicrobium, were observed by means of shotgun metagenomic sequencing at 10 kg COD m-3 d-1, as well as the acetoclastic archaea Methanosaeta and prevalence of genes encoding enzymes related to acetoclastic methanogenesis. It was concluded that process efficiency and methane production occurred even in higher sulfate concentrations due to glycerol addition.

Phosphate solubilization by Antarctic yeasts isolated from lichens.

Antarctica has a great diversity of microorganisms with biotechnological potential but is not very well Known about yeasts with phosphate solubilization activity. Thus, the aim of this study was to evaluate the ability of yeasts from Antarctica lichens to solubilize phosphate in vitro. In the screening, 147 yeasts were tested and 43 (29%) showed P solubilization in solid NBRIP medium at 15.0 °C, with a higher prevalence of positive genera Vishniacozyma, followed by Cystobasidium. Most of the positive yeasts were isolated from Usnea auratiacoatra, followed by Polycauliona regalis and Lecania brialmontii. Two strains with better activity after screening were selected for the solubilization in the liquid medium, Vishniacozyma victoriae 2.L15 and A.L6 (unidentified). Vishniacozyma victoriae 2.L15 exhibiting activities at 25.0 °C (29.91 mg/L of phosphate and pH 6.85) and at 30.0 °C (619.04 mg/L of phosphate and pH 3.73) and A.L6 strain at 25.0 °C (25.05 mg/L of phosphate and pH 6.69) and at 30.0 °C (31.25 mg/L of phosphate and pH 6.47). Of eight organic acids tested by HPLC, tartaric and acetic acids were detected during phosphate solubilization, with greater release in the period of 144 (2.13 mg/L) and 72 (13.72 mg/L) hours, respectively. Future studies to elucidate the presence of functional genes for P metabolism in lichens, as well as studies in the field of proteomics for the discovery of yeast proteins related to P solubilization are needed. Thus, the high prevalence of lichen-associated yeast communities probably contributed to the high frequency of phosphate-solubilizing isolates in this study.

Cultured and uncultured microbial community associated with biogas production in anaerobic digestion processes.

The search for sustainable development has increased interest in the improvement of technologies that use renewable energy sources. One of the alternatives in the production of renewable energy comes from the use of waste including urban solids, animal excrement from livestock, and biomass residues from agro-industrial plants. These materials may be used in the production of biogas, making its production highly sustainable and environmentally friendly. The present study aimed to evaluate the cultivated and uncultivated microbial community from a substrate (starter) used as an adapter for biogas production in anaerobic digestion processes. 16S rDNA metabarcoding revealed the domain of bacteria belonging to the phyla Firmicutes, Bacteroidota, Chloroflexi and Synergistota. The methanogenic group was represented by the phyla Halobacterota and Euryarchaeota. Through 16S rRNA sequencing of isolates recovered from the starter culture, the genera Rhodococcus (Actinobacteria phylum), Vagococcus, Lysinibacillus, Niallia, Priestia, Robertmurraya, Proteiniclasticum (Firmicutes phylum), and Luteimonas (Proteobacteria phylum) were identified, genera that were not observed in the metabarcoding data. The volatile solids, volatile organic acids, and total inorganic carbon reached 659.10 g kg-1, 717.70 g kg-1, 70,005.0 g kg-1, respectively. The cultured groups are involved in the metabolism of sugars and other compounds derived from lignocellulosic material, as well as in anaerobic methane production processes. The results demonstrate that culture-dependent approaches, such as isolation and sequencing, and culture-independent studies, such as the Metabarcoding approach, are complementary methodologies that, when integrated provide robust and comprehensive information about the microbial communities involved in processes of the production of biogas in anaerobic digestion processes.

Hydrogen and organic acid production from dark fermentation of cheese whey without buffers under mesophilic condition.

BioH2 production from cheese whey (CW) was evaluated in two acidogenic reactors, UASB and structured fixed-bed (FB), without pH adjustment, under mesophilic conditions, and OLR of 25-90 g COD/L.d. Stage 1 was conducted as a control experiment using sucrose. BioH2 production occurred under pH < 3.0 with maximum yields of 5.8 and 3.0 mol H2/mol sucroseconsumed for UASB and FB reactors, respectively. In Stage 2, CW was the only substrate and a negligible bioH2 production was observed. Nevertheless, a maximum lactic acid concentration of 9.6 g/L was obtained, indicating that pH adjustment can be non-essential for lactic acid production from CW. In Stage 3, a strategy to enrich hydrogenogenic biomass was conducted by initially feeding the reactors with sucrose and gradually replacing it by CW. This strategy brought better bioH2 results compared to Stage 2, but it could not bear over the long-term, as non-hydrogen producing bacteria became predominant.

New Insights into Controlling Homoacetogenesis in the Co-digestion of Coffee Waste: Effect of Operational Conditions and Characterization of Microbial Communities.

In this research batch reactors were operated with coffee processing waste and autochthonous microbial consortium, and a taxonomic and functional analysis was performed for phase I of stabilization of maximum H2 production and for phase II of maximum H2 consumption. During phase I, the reactor's operating conditions were pH 4.84 to 8.18, headspace 33.18% to 66.82%, and pulp and husk from 6.95 to 17.05 g/L. These assays continued for phase II, with initial pH conditions of 5.8-8.1, headspace of 33.18-66.82%, and pulp and husk remaining from phase I. The highest homoacetogenesis was observed in assay 5 with pH 7.7, 40% headspace, and 15 g/L of pulp and husk (initial concentrations of phase I). A relative abundance of Clostridium 41%, Lactobacillus 20% and Acetobacter 14% was observed in phase I. In phase II, there was a change in relative abundance of 21%, 63%, and 1%, respectively, and functional genes involved with autotrophic (formyltetrahydrofolate synthase) and heterotrophic (enolase) homoacetogenesis, butanol (3-hydroxybutyryl-CoA dehydrogenase), and propionic acid (propionate CoA-transferase) were identified. This study provides a new and amplified insight into the physicochemical and microbiological factors, which can be used to propose adequate operational conditions to maximize the bioenergy production and reduce homoacetogenesis in biological reactors.

Pharmaceutical biotechnological potential of filamentous fungi isolated from textile industry.

The need for more effective drugs for the treatment of infectious diseases as well as for general applications including wound healing and burn surgery, has guided efforts for the discovery of new compounds of medical interest. Microorganisms found in textile industrial waste have the ability to produce a variety of enzymes and/or secondary metabolites including molecules of pharmaceutical interest. The present work investigated the biotechnological potential of filamentous fungi isolated from textile industry wastewater for the production of collagenase and antimicrobial metabolites. From 28 isolates assayed, Sarocladium sp. ITF33 showed specific collagenolytic activity with values of 7.62 and 9.04 U mg-1 for the intracellular and extracellular fractions, respectively. The isolate Penicillium sp. ITF28 showed the best antimicrobial activity, reaching MIC ranging from 1.0 to 0.0625 mg mL-1 against five pathogenic bacteria. Molecular analyzes suggest that the isolate Sarocladium sp. ITF 33 can be considered a species not yet described. The results of the present work encourage studies of characterization and purification of the enzymes and secondary metabolites produced by the isolates found aiming future applications in the medical and pharmaceutical fields.

Antimicrobial activity against Microcystis aeruginosa and degradation of microcystin-LR by bacteria isolated from Antarctica.

Cyanobacteria massive proliferations are common in freshwater bodies worldwide, causing adverse effects on aquatic ecosystems and public health. Numerous species develop blooms. Most of them correspond to the toxic microcystin-producing cyanobacterium Microcystis aeruginosa. Microorganisms recovered from Antarctic environment can be considered an unexploited source of antimicrobial compounds. Data about their activity against cyanobacteria are scant or inexistent. This study aimed to evaluate the capacity of Antarctic bacteria to inhibit the proliferation of M. aeruginosa BCPUSP232 and to degrade microcystin-LR (MC-LR). Cell-free extracts of seventy-six bacterial strains were initially tested for antimicrobial activity. Unidentified (UN) strains 62 and ES7 and Psychromonas arctica were able to effectively lyse M. aeruginosa. Eight strains showed MIC ranging from 0.55 to 3.00 mg mL-1, with ES7 showing the best antimicrobial activity. Arthrobacter sp. 443 and UN 383 were the most efficient in degrading MC-LR, with 24.87 and 23.85% degradation, respectively. To our knowledge, this is the first report of antimicrobial and MC-LR degradation activities by Antarctic bacteria, opening up perspectives for their future application as an alternative or supporting approach to help mitigate cyanobacterial blooms.

Effect of biostimulation and bioaugmentation on hydrocarbon degradation and detoxification of diesel-contaminated soil: a microcosm study.

Soil contamination with diesel oil is quite common during processes of transport and storage. Bioremediation is considered a safe, economical, and environmentally friendly approach for contaminated soil treatment. In this context, studies using hydrocarbon bioremediation have focused on total petroleum hydrocarbon (TPH) analysis to assess process effectiveness, while ecotoxicity has been neglected. Thus, this study aimed to select a microbial consortium capable of detoxifying diesel oil and apply this consortium to the bioremediation of soil contaminated with this environmental pollutant through different bioremediation approaches. Gas chromatography (GC-FID) was used to analyze diesel oil degradation, while ecotoxicological bioassays with the bioindicators Artemia sp., Aliivibrio fischeri (Microtox), and Cucumis sativus were used to assess detoxification. After 90 days of bioremediation, we found that the biostimulation and biostimulation/bioaugmentation approaches showed higher rates of diesel oil degradation in relation to natural attenuation (41.9 and 26.7%, respectively). Phytotoxicity increased in the biostimulation and biostimulation/bioaugmentation treatments during the degradation process, whereas in the Microtox test, the toxicity was the same in these treatments as that in the natural attenuation treatment. In both the phytotoxicity and Microtox tests, bioaugmentation treatment showed lower toxicity. However, compared with natural attenuation, this approach did not show satisfactory hydrocarbon degradation. Based on the microcosm experiments results, we conclude that a broader analysis of the success of bioremediation requires the performance of toxicity bioassays.

Antarctic lichens as a source of phosphate-solubilizing bacteria.

In association with lichens, bacteria can play key roles in solubilizing sources of inorganic phosphates that are available in the environment. In this study, the potential of bacteria isolated from 15 Antarctic lichen samples for phosphate solubilization was investigated. From 124 bacteria tested, 66 (53%) were positive for phosphate solubilization in solid NBRIP medium, with a higher prevalence of Pseudomonas, followed by Caballeronia and Chryseobacterium. Most of the phosphate-solubilizing bacteria were isolated from Usnea auratiacoatra, followed by Caloplaca regalis and Xanthoria candelaria. Two isolates showed outstanding performance, Pseudomonas sp. 11.LB15 and Pseudomonas sp. 1.LB34, since they presented solubilization in the temperature range from 15.0 to 30.0 °C, and maximum quantification of soluble phosphate at 25.0 °C was 511.21 and 532.07 mg/L for Pseudomonas sp. 11.LB15 and Pseudomonas sp. 1.LB34, respectively. At 30.0 °C soluble phosphate yield was 639.43 and 518.95 mg/L with pH of 3.74 and 3.87 for Pseudomonas sp. 11.LB15 and Pseudomonas sp. 1.LB34, respectively. Fumaric and tartaric acids were released during the solubilization process. Finally, bacteria isolated from Antarctic lichens were shown to have the potential for phosphate solubilization, opening perspectives for future application in the agricultural sector and contributing to reduce the use of chemical fertilizers.

Pigments from Antarctic bacteria and their biotechnological applications.

Pigments from microorganisms have triggered great interest in the market, mostly by their "natural" appeal, their favorable production conditions, in addition to the potential new chemical structures or naturally overproducing strains. They have been used in: food, feed, dairy, textile, pharmaceutical, and cosmetic industries. The high rate of pigment production in microorganisms recovered from Antarctica in response to selective pressures such as: high UV radiation, low temperatures, and freezing and thawing cycles makes this a unique biome which means that much of its biological heritage cannot be found elsewhere on the planet. This vast arsenal of pigmented molecules has different functions in bacteria and may exhibit different biotechnological activities, such as: extracellular sunscreens, photoprotective function, antimicrobial activity, biodegradability, etc. However, many challenges for the commercial use of these compounds have yet to be overcome, such as: the low stability of natural pigments in cosmetic formulations, the change in color when subjected to pH variations, the low yield and the high costs in their production. This review surveys the different types of natural pigments found in Antarctic bacteria, classifying them according to their chemical structure. Finally, we give an overview of the main pigments that are used commercially today.

Metagenomic Insights Into the Mechanisms for Biodegradation of Polycyclic Aromatic Hydrocarbons in the Oil Supply Chain.

Petroleum is a very complex and diverse organic mixture. Its composition depends on reservoir location and in situ conditions and changes once crude oil is spilled into the environment, making the characteristics associated with every spill unique. Polycyclic aromatic hydrocarbons (PAHs) are common components of the crude oil and constitute a group of persistent organic pollutants. Due to their highly hydrophobic, and their low solubility tend to accumulate in soil and sediment. The process by which oil is sourced and made available for use is referred to as the oil supply chain and involves three parts: (1) upstream, (2) midstream and (3) downstream activities. As consequence from oil supply chain activities, crude oils are subjected to biodeterioration, acidification and souring, and oil spills are frequently reported affecting not only the environment, but also the economy and human resources. Different bioremediation techniques based on microbial metabolism, such as natural attenuation, bioaugmentation, biostimulation are promising approaches to minimize the environmental impact of oil spills. The rate and efficiency of this process depend on multiple factors, like pH, oxygen content, temperature, availability and concentration of the pollutants and diversity and structure of the microbial community present in the affected (contaminated) area. Emerging approaches, such as (meta-)taxonomics and (meta-)genomics bring new insights into the molecular mechanisms of PAH microbial degradation at both single species and community levels in oil reservoirs and groundwater/seawater spills. We have scrutinized the microbiological aspects of biodegradation of PAHs naturally occurring in oil upstream activities (exploration and production), and crude oil and/or by-products spills in midstream (transport and storage) and downstream (refining and distribution) activities. This work addresses PAH biodegradation in different stages of oil supply chain affecting diverse environments (groundwater, seawater, oil reservoir) focusing on genes and pathways as well as key players involved in this process. In depth understanding of the biodegradation process will provide/improve knowledge for optimizing and monitoring bioremediation in oil spills cases and/or to impair the degradation in reservoirs avoiding deterioration of crude oil quality.

Undecane production by cold-adapted bacteria from Antarctica.

In the last decades, efforts to reduce the use of fossil fuels have increased the search for alternative sustainable sources of renewable energy. In this scenario, hydrocarbons derived from fatty acids are among the compounds that have been drawing attention. The intracellular production of hydrocarbons by bacteria derived from cold environments such as the Antarctic continent is currently poorly investigated, as extremophilic microorganisms provide a great range of metabolic capabilities and may represent a key tool in the production of biofuels. The aim of this study was to explore the ability of bacterial cells derived from extreme environments to produce hydrocarbons with potential for further use as biofuels. Seven bacteria isolated from Antarctic samples were evaluated for hydrocarbon production using GC-MS approaches. Two isolates, identified as Arthrobacter livingstonensis 593 and Pseudoalteromonas arctica 628, were able to produce the hydrocarbon undecane (CH3-(CH2)9-CH3) in concentrations of 1.39 mg L-1 and 1.81 mg L-1, respectively. Results from the present work encourage further research focusing on the optimization of hydrocarbon production by the isolates identified as producers, which may be used in further aircraft biofuel production. This is the first report on the production of the undecane compound by bacteria isolated from waterlogged soil and sponge from Antarctica.

Actinobacteria from Antarctica as a source for anticancer discovery.

Although many advances have been achieved to treat aggressive tumours, cancer remains a leading cause of death and a public health problem worldwide. Among the main approaches for the discovery of new bioactive agents, the prospect of microbial secondary metabolites represents an effective source for the development of drug leads. In this study, we investigated the actinobacterial diversity associated with an endemic Antarctic species, Deschampsia antarctica, by integrated culture-dependent and culture-independent methods and acknowledged this niche as a reservoir of bioactive strains for the production of antitumour compounds. The 16S rRNA-based analysis showed the predominance of the Actinomycetales order, a well-known group of bioactive metabolite producers belonging to the Actinobacteria phylum. Cultivation techniques were applied, and 72 psychrotolerant Actinobacteria strains belonging to the genera Actinoplanes, Arthrobacter, Kribbella, Mycobacterium, Nocardia, Pilimelia, Pseudarthrobacter, Rhodococcus, Streptacidiphilus, Streptomyces and Tsukamurella were identified. The secondary metabolites were screened, and 17 isolates were identified as promising antitumour compound producers. However, the bio-guided assay showed a pronounced antiproliferative activity for the crude extracts of Streptomyces sp. CMAA 1527 and Streptomyces sp. CMAA 1653. The TGI and LC50 values revealed the potential of these natural products to control the proliferation of breast (MCF-7), glioblastoma (U251), lung/non-small (NCI-H460) and kidney (786-0) human cancer cell lines. Cinerubin B and actinomycin V were the predominant compounds identified in Streptomyces sp. CMAA 1527 and Streptomyces sp. CMAA 1653, respectively. Our results suggest that the rhizosphere of D. antarctica represents a prominent reservoir of bioactive actinobacteria strains and reveals it as an important environment for potential antitumour agents.

The influence of upflow velocity and hydraulic retention time changes on taxonomic and functional characterization in Fluidized Bed Reactor treating commercial laundry wastewater in co-digestion with domestic sewage.

A large-scale (19.8L) Fluidized Bed Reactor (FBR) operated for 592 days was used to assess the removal performance of linear alkylbenzene sulfonate (LAS). Adjustments in hydraulic retention time (HRT) (18 and 30 h), ethanol (50, 100, 200 mg L-1) and linear alkylbenzene sulfonate (LAS) concentration (6.3-24.7 mg L-1) with taxonomic and functional characterization of biomass using Whole Genome Shotgun Metagenomic (WGSM) represented a major step forward for optimizing biological treatments of LAS. In addition, the variation of the upflow velocity (0.5, 0.7 and 0.9 cm s-1) was investigated, which is a parameter that had not yet been correlated with the possibilities of LAS removal in FBR. Lower Vup (0.5 cm s-1) allied to higher ethanol concentration (200 mg L-1) resulted in lower LAS removal (29%) with predominance of methanogenic archaea and genes related to methanogenesis, while higher Vup (0.9 cm s-1) led to aerobic organisms and oxidative phosphorylation genes. An intermediate Vup (0.7 cm s-1) and higher HRT (30 h) favored sulfate reducing bacteria and genes related to sulfur metabolism, which resulted in the highest LAS (83%) and COD (77%) removal efficiency.

In depth metagenomic analysis in contrasting oil wells reveals syntrophic bacterial and archaeal associations for oil biodegradation in petroleum reservoirs.

Microbial biodegradation of hydrocarbons in petroleum reservoirs has major consequences in the petroleum value and quality. The identification of microorganisms capable of in-situ degradation of hydrocarbons under the reservoir conditions is crucial to understand microbial roles in hydrocarbon transformation and the impact of oil exploration and production on energy resources. The aim of this study was to profile the metagenome of microbial communities in crude oils and associated formation water from two high temperature and relatively saline oil-production wells, where one has been subjected to water flooding (BA-2) and the other one is considered pristine (BA-1). The microbiome was studied in the fluids using shotgun metagenome sequencing. Distinct microbial compositions were revealed when comparing pristine and water flooded oil wells in contrast to the similar community structures observed between the aqueous and oil fluids from the same well (BA-2). The equal proportion of archaea and bacteria together with the greater anaerobic hydrocarbon degradation potential in the BA-1 pristine but degraded reservoir contrasted with the predominance of bacteria over archaea, aerobic pathways and lower frequency of anaerobic degradation genes in the BA-2 water flooded undegraded well. Our results suggest that Syntrophus, Syntrophomonas, candidatus Atribacteria and Synergistia, in association with mainly acetoclastic methanogenic archaea of the genus Methanothrix, were collectively responsible for the oil biodegradation observed in the pristine petroleum well BA-1. Conversely, the microbial composition of the water flooded oil well BA-2 was mainly dominated by the fast-growing and putatively aerobic opportunists Marinobacter and Marinobacterium. This presumable allochthonous community introduced a greater metabolic versatility, although oil biodegradation has not been detected hitherto perhaps due to in-reservoir unfavorable physicochemical conditions. These findings provide a better understanding of the petroleum reservoir microbiomes and their potential roles in biogeochemical processes occurring in environments with different geological and oil recovery histories.

Physicochemical characterization of Pseudomonas stutzeri UFV5 and analysis of its transcriptome under heterotrophic nitrification/aerobic denitrification pathway induction condition.

Biological ammonium removal via heterotrophic nitrification/aerobic denitrification (HN/AD) presents several advantages in relation to conventional removal processes, but little is known about the microorganisms and metabolic pathways involved in this process. In this study, Pseudomonas stutzeri UFV5 was isolated from an activated sludge sample from oil wastewater treatment station and its ammonium removal via HN/AD was investigated by physicochemical and molecular approaches to better understand this process and optimize the biological ammonium removal in wastewater treatment plants. Results showed that P. stutzeri UFV5 removed all the ammonium in 48-72 hours using pyruvate, acetate, citrate or sodium succinate as carbon sources, C/N ratios 6, 8, 10 and 12, 3-6% salinities, pH 7-9 and temperatures of 20-40 °C. Comparative genomics and PCR revealed that genes encoding the enzymes involved in anaerobic denitrification process are present in P. stutzeri genome, but no gene that encodes enzymes involved in autotrophic nitrification was found. Furthermore, transcriptomics showed that none of the known enzymes of autotrophic nitrification and anaerobic denitrification had their expression differentiated and an upregulation of the biosynthesis machinery and protein translation was observed, besides several genes with unknown function, indicating a non-conventional mechanism involved in HN/AD process.

Mangrove soil as a source for novel xylanase and amylase as determined by cultivation-dependent and cultivation-independent methods.

Xylanase and α-amylase enzymes participate in the degradation of organic matter, acting in hemicellulose and starch mineralization, respectively, and are in high demand for industrial use. Mangroves represent a promising source for bioprospecting enzymes due to their unique characteristics, such as fluctuations in oxic/anoxic conditions and salinity. In this context, the present work aimed to bioprospect xylanases from mangrove soil using cultivation-dependent and cultivation-independent methods. Through screening from a metagenomic library, three potentially xylanolytic clones were obtained and sequenced, and reads were assembled into contigs and annotated. The contig MgrBr135 was affiliated with the Planctomycetaceae family and was one of 30 ORFs selected for subcloning that demonstrated only amylase activity. Through the cultivation method, 38 bacterial isolates with xylanolytic activity were isolated. Isolate 11 showed an enzymatic index of 10.9 using the plate assay method. Isolate 39 achieved an enzyme activity of 0.43 U/mL using the colorimetric method with 3,5-dinitrosalicylic acid. Isolate 39 produced xylanase on culture medium with salinity ranging from 1.25 to 5%. Partial 16S rRNA gene sequencing identified isolates in the Bacillus and Paenibacillus genera. The results of this study highlight the importance of mangroves as an enzyme source and show that bacterial groups can be used for starch and hemicellulose degradation.

Hydrocarbon-associated substrates reveal promising fungi for poly (ethylene terephthalate) (PET) depolymerization.

Recalcitrant characteristics and insolubility in water make the disposal of synthetic polymers a great environmental problem to be faced by modern society. Strategies towards the recycling of post-consumer polymers, like poly (ethylene terephthalate, PET) degradation/depolymerization have been studied but still need improvement. To contribute with this purpose, 100 fungal strains from hydrocarbon-associated environments were screened for lipase and esterase activities by plate assays and high-throughput screening (HTS), using short- and long-chain fluorogenic probes. Nine isolates were selected for their outstanding hydrolytic activity, comprising the genera Microsphaeropsis, Mucor, Trichoderma, Westerdykella, and Pycnidiophora. Two strains of Microsphaeropsis arundinis were able to convert 2-3% of PET nanoparticle into terephthalic acid, and when cultured with two kinds of commercial PET bottle fragments, they also promoted weight loss, surface and chemical changes, increased lipase and esterase activities, and led to PET depolymerization with release of terephthalic acid at concentrations above 20.0 ppm and other oligomers over 0.6 ppm. The results corroborate that hydrocarbon-associated areas are important source of microorganisms for application in environmental technologies, and the sources investigated revealed important strains with potential for PET depolymerization.