Individual Bacterial Strains Research Articles

Bioremediation of soils contaminated with nicosulfuron by the bacterial complex ES58

Nicosulfuron residues in soil can be harmful to the environment. In this study, acid-producing Klebsiella oxytoca ES5 and Klebsiella grimontii ES8 were isolated to construct the ES58 bacterial complex. The culture medium was optimized using response surface methodology, nicosulfuron degradation by ES58 reached 97.21% in 96h. The optimal degradation conditions were: temperature: 25℃, pH 6, initial nicosulfuron concentration: 50mgL-1 and inoculum volume: 2%. The two individual strains and the bacterial complex were tested for the ability of nitrogen fixation, phosphorus solubilization, potassium decomposition and iron carrier production. The results revealed that both strains and the bacterial complex had the ability to promote the growth, with bacterial complex being more capable than the two individual bacterial strains. After 28 d of bioremediation of nicosulfuron-contaminated soil by ES58, degradation rate of nicosulfuron was 90.84% in the unsterilized soil. Furthermore, the remediation process restored the activities of catalase, invertase, dehydrogenase and urease in the soil. The ES5-specific gene budA and ES8-specific gene ldh were detected in the soil at the 28th day. ES58 exhibited different effects on the growth indexes of nicosulfuron-sensitive crops. The study provides a novel strategy for nicosulfuron degradation effective by constructing and utilizing bacterial complex.

Effectiveness of Biological Approaches for Removing Persistent Organic Pollutants from Wastewater: A Mini-Review.

Persistent organic pollutants (POPs), including organochlorine pesticides, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzo-p-furans, pose significant hazards to the environment and living organisms. This concise review aims to consolidate knowledge on the biological processes involved in removing POPs from wastewater, an area less explored compared to conventional physico-chemical methods. The focus is on the potential of various aerobic and anaerobic microorganisms, fungi, and bacteria for efficient bioremediation, mitigating or eradicating the deleterious effects of these chemicals. The review scrutinizes individual bacterial strains and mixed cultures engaged in breaking down persistent organic pollutants in water, highlighting promising results from laboratory investigations that could be scaled for practical applications. The review concludes by underscoring the opportunities for exploring and advancing more sophisticated bioremediation techniques and optimized bioreactors. The ultimate goal is to enhance the efficiency of microbial-based strategies, implicitly reducing the environmental impact of persistent chemicals.

Graphene in Medicine: Revolutionizing Healthcare through Advanced Nanomaterials

Nanomaterials, particularly carbon-based structures like graphene nanostructures, have revolutionized science and technology, offering groundbreaking advancements in bioengineering and medicine. These developments have enhanced our ability to detect, diagnose, and treat diseases, leading to significant innovations in therapy methods. The evolving field of graphene synthesis, with its less complex and more effective strategies, has captured the scientific community's interest. This review seeks to delve into the latest progress in the creation and application of graphene-based nanomaterials, especially their role in biomedical applications, with a primary focus on drug delivery systems. Graphene has emerged as a versatile material in the medical field. Its application as a sensor in monitoring vital parameters such as blood pressure and blood sugar levels, as well as nitric oxide levels in oxygen, has been noteworthy. In dentistry, graphene, combined with specific peptides, can identify individual bacterial strains, aiding in accurate disease diagnosis. Its role as an immunosensor is also significant, enabling the detection of trace amounts of substances like growth hormones. In the battle against cancer, graphene has shown promising results. It is actively being researched for broader medical applications including cancer therapy, diagnostic tools for diseases, tissue engineering, implants, DNA sequencing, biomarker identification, genetic material transfer, and in the combined fields of biomedical imaging and neuroscience. This review underscores the potential of graphene in medical science. As research continues, it is anticipated that graphene-based technologies will significantly contribute to personalized therapies, enhancing healthcare quality. The conclusion of this review emphasizes the need for ongoing research to explore and refine graphene-derived smart therapeutics. Such advancements will not only improve patient care but also drive us towards the zenith of human welfare, showcasing the transformative impact of nanotechnology in healthcare.Keywords: Graphene, Biomedical Applications, Drug Delivery Systems, Diagnostic Innovations and Personalized Therapeutics

Coordinated influence of Funneliformis mosseae and different plant growth-promoting bacteria on growth, root functional traits, and nutrient acquisition by maize.

Rhizospheric interactions among plant roots, arbuscular mycorrhizal fungi, and plant growth-promoting bacteria (PGPB) can enhance plant health by promoting nutrient acquisition and stimulating the plant immune system. This pot experiment, conducted in autoclaved soil, explored the synergistic impacts of the arbuscular mycorrhizal fungus Funneliformis mosseae with four individual bacterial strains, viz.: Cronobacter sp. Rz-7, Serratia sp. 5-D, Pseudomonas sp. ER-20 and Stenotrophomonas sp. RI-4A on maize growth, root functional traits, root exudates, root colonization, and nutrient uptake. The comprehensive biochemical characterization of these bacterial strains includes assessments of mineral nutrient solubilization, plant hormone production, and drought tolerance. The results showed that all single and interactive treatments of the mycorrhizal fungus and bacterial strains improved maize growth, as compared with the control (no fungus or PGPB). Among single treatments, the application of the mycorrhizal fungus was more effective than the bacterial strains in stimulating maize growth. Within the bacterial treatments, Serratia sp. 5-D and Pseudomonas sp. ER-20 were more effective in enhancing maize growth than Cronobacter sp. Rz-7 and Stenotrophomonas sp. RI-4A. All bacterial strains were compatible with Funneliformis mosseae to improve root colonization and maize growth. However, the interaction of mycorrhiza and Serratia sp. 5-D (M + 5-D) was the most prominent for maize growth improvement comparatively to all other treatments. We observed that bacterial strains directly enhanced maize growth while indirectly promoting biomass accumulation by facilitating increased mycorrhizal colonization, indicating that these bacteria acted as mycorrhizal helper bacteria.

Efficient degradation of methyl red dye from the aqueous solution by individual bacterial and their consortium in a sugarcane bagasse waste-based media

Dye is one of the major pollutions around the whole world which have adverse effects on the environment and human beings. There is a requirement for an efficient, reliable, sustainable, and eco-friendly approach to the removal of dyes. In the present research, three individual bacterial strains Enterobacter aerogenes (MBX6), Klebsiella pneumoniae (MBC34), and Micrococcus luteus (MBC23) and their consortium was used to remove Methyl Red (MR) dye. The dye removal was observed at different initial concentrations of dye, nutrient media, additives in the nutrient media and sugarcane bagasse extract as a bacterial growth medium. The outcomes of the study showed that the bacterial consortium exhibits better removal efficiencies (63.6%) than individual bacterial strains and the dye removal percentage (75.19%) enhanced with increasing concentration of sucrose (3%) which was used as media additive. The addition of the sugar in nutrient medium resulted in more effective dye removal. The maximum removal of MR dye (98.6%) was achieved when the consortium was grown in a media containing pure sugarcane bagasse extract. The use of sugarcane bagasse extract (agricultural waste product) as a novel growth medium for the cultivation of bacteria possessing dye removal capabilities can offer a sustainable and cost-effective solution for industrial wastewater treatment.

Cultivated Enterococcus faecium B6 from children with obesity promotes nonalcoholic fatty liver disease by the bioactive metabolite tyramine

ABSTRACT Gut microbiota plays an essential role in nonalcoholic fatty liver disease (NAFLD). However, the contribution of individual bacterial strains and their metabolites to childhood NAFLD pathogenesis remains poorly understood. Herein, the critical bacteria in children with obesity accompanied by NAFLD were identified by microbiome analysis. Bacteria abundant in the NAFLD group were systematically assessed for their lipogenic effects. The underlying mechanisms and microbial-derived metabolites in NAFLD pathogenesis were investigated using multi-omics and LC-MS/MS analysis. The roles of the crucial metabolite in NAFLD were validated in vitro and in vivo as well as in an additional cohort. The results showed that Enterococcus spp. was enriched in children with obesity and NAFLD. The patient-derived Enterococcus faecium B6 (E. faecium B6) significantly contributed to NAFLD symptoms in mice. E. faecium B6 produced a crucial bioactive metabolite, tyramine, which probably activated PPAR-γ, leading to lipid accumulation, inflammation, and fibrosis in the liver. Moreover, these findings were successfully validated in an additional cohort. This pioneering study elucidated the important functions of cultivated E. faecium B6 and its bioactive metabolite (tyramine) in exacerbating NAFLD. These findings advance the comprehensive understanding of NAFLD pathogenesis and provide new insights for the development of microbe/metabolite-based therapeutic strategies.

Phytochemical Characterization and Antibacterial Activity of Albanian Juniperus communis and Juniperus oxycedrus Berries and Needle Leaves Extracts.

This paper aims to investigate the phytochemical profile and in vitro antibacterial activity of two juniper species collected in Albania, Juniperus communis and Juniperus oxycedrus. The berries and the needle leaves were subjected to solid-liquid solvent ultrasound-assisted extraction. The phytochemical characterization of the extracts was performed by spectrophotometric and chromatographic means. The extract of J. communis berries (JcB) showed a higher total phenolic and flavonoid content (3.04 ± 0.09 mg GAE/g DW, and 1.14 ± 0.36 mg QE/g DW, respectively), also a higher antioxidant activity from DPPH and ABTS radical screening assays, compared to J. oxycedrus berries (JoxB) extract. The extract of J. oxycedrus needle leaves (JoxL) prevailed in total flavonoid content (10.55 ± 0.24 mg QE/g DW), and ABTS assays (1.83 ± 0.01 mM TE/g DW), compared to the extract of J. communis needle leaves (JcL). The chromatographic analysis revealed the presence of ellagic acid and kaempferol in all the samples. Ellagic acid was the main identified compound with the highest quantity in the extracts of JoxB, JoxL, and JcB with an average of 445.69 ± 0.96 µg/g, 2890.05 ± 0.29 µg/g, and 8133.83 ± 4.03 µg/g, respectively. The antibacterial potential of the ethanolic extracts was evaluated on Bacillus spp., Escherichia coli, and Staphylococcus aureus. In the Agar Well Diffusion Assay, it was observed that all the tested bacterial strains were sensitive to the extracts, whereas selected extracts showed a similar inhibition activity rate compared with the antibiotic substance (Chloramphenicol), used as a positive control. The extracts showed a similar minimal inhibitory and bactericidal concentration for the individual bacterial strains, suggesting that J. communis and J. oxycedrus extracts have a similar potential in antibacterial activity.

Quantifying how much host, pathogen, and other factors affect human protective adaptive immune responses.

Recognizing the "essential" factors that contribute to a clinical outcome is critical for designing appropriate therapies and prioritizing limited medical resources. Demonstrating a high correlation between a factor and an outcome does not necessarily imply an essential role of the factor to the outcome. Human protective adaptive immune responses to pathogens vary among (and perhaps within) pathogenic strains, human individual hosts, and in response to other factors. Which of these has an "essential" role? We offer three statistical approaches that predict the presence of newly contributing factor(s) and then quantify the influence of host, pathogen, and the new factors on immune responses. We illustrate these approaches using previous data from the protective adaptive immune response (cellular and humoral) by human hosts to various strains of the same pathogenic bacterial species. Taylor's law predicts the existence of other factors potentially contributing to the human protective adaptive immune response in addition to inter-individual host and intra-bacterial species inter-strain variability. A mixed linear model measures the relative contribution of the known variables, individual human hosts and bacterial strains, and estimates the summed contributions of the newly predicted but unknown factors to the combined adaptive immune response. A principal component analysis predicts the presence of sub-variables (currently not defined) within bacterial strains and individuals that may contribute to the combined immune response. These observations have statistical, biological, clinical, and therapeutic implications.

Application of multi-species microbial bioassay for toxicity risk assessment LumiMARA luminometric tests and chemical analyses to assess water quality in the świętokrzyskie voivodeship

The area of Świętokrzyskie voivodeship is located within the range of several macro-regions, the parent rocks are highly differentiated, which affects the diversity of soil and water conditions. and water conditions. The weakest soils occur in the central and northern parts, the best soils in the eastern and southern parts of the Świętokrzyskie Voivodeship. The study presents selected physicochemical properties of groundwaters captured by borehole wells and spring waters in selected areas of the and spring waters in selected areas of the swietokrzyskie voivodeship. The analysed water was subjected to toxicity analysis using multispecies LumiMARA test (Microbial Assay for Risc Assessment) and physicochemical parameters were determined - pH, carbonate hardness and total hardness, conductivity, OWO and chlorides. The water samples for the study were collected at different times of the year 2021- January, April, July, November. The conductivity of the tested waters, regardless of the source of origin, varies by location. The aim of the study was to analyze the quality of water due to ground and water conditions and very high interest and use of water from the studied sources by the inhabitants of the regions. The study showed that the analysed waters contained toxic substances in concentrations exceeding the WHO recommendations. Chemical analyses were reflected in ecotoxicological analyses, which showed toxic effects on individual bacterial strains and allowed the waters to be classified into individual toxicity classes.

Polyethylene Biodegradation by an Artificial Bacterial Consortium: Rhodococcus as a Competitive Plastisphere Species.

Polyethylene (PE), a widely used recalcitrant synthetic polymer, is a major global pollutant. PE has very low biodegradability due to its rigid C-C backbone and high hydrophobicity. Although microorganisms have been suggested to possess PE-degrading enzymes, our understanding of the PE biodegradation process and its overall applicability is still lacking. In the present study, we used an artificial bacterial consortium for PE biodegradation to compensate for the enzyme availability and metabolic capabilities of individual bacterial strains. Consortium members were selected based on available literature and preliminary screening for PE-degrading enzymes, including laccases, lipases, esterases, and alkane hydroxylases. PE pellets were incubated with the consortium for 200 days. A next-generation sequencing ana-lysis of the consortium community of the culture broth and on the PE pellet identified Rhodococcus as the dominant bacteria. Among the Rhodococcus strains in the consortium, Rhodococcus erythropolis was predominant. Scanning electron microscopy (SEM) revealed multilayered biofilms with bacteria embedded on the PE surface. SEM micrographs of PE pellets after biofilm removal showed bacterial pitting and surface deterioration. Multicellular biofilm structures and surface biodeterioration were observed in an incubation of PE pellets with R. erythropolis alone. The present study demonstrated that PE may be biodegraded by an artificially constructed bacterial consortium, in which R. erythropolis has emerged as an important player. The results showing the robust colonization of hydrophobic PE by R. erythropolis and that it naturally possesses and extracellularly expresses several target enzymes suggest its potential as a host for further improved PE biodeterioration by genetic engineering technology using a well-studied host-vector system.

Array-based specific classification of bacterial species via ligands with dimethylamino/amino groups.

The early detection of bacterial species plays a crucial role in patient prognosis and the development of effective therapeutic regimens. This study introduces an accessible and promising colorimetric sensor array designed to classify gram-positive (G+) and gram-negative (G-) bacterial species. The classification relies on 6 chemical ligands with dimethylamino/amino groups as sensing elements and silver nanotriangles as colorimetric probes. Using these specific sensor arrays, we successfully differentiated G- and G+ bacterial species and discriminated individual bacterial strains, and the sensors exhibited remarkable reproducibility and high sensitivity. Moreover, the sensor array can identify bacterial mixtures and bacteria at varying concentrations, underscoring its versatility. In summary, this sensor array offers an effective tool for bacterial analysis with promising applications in the field of biomedical diagnostics.

Biodegradation of pyrene by bacterial consortia: Impact of natural surfactants and iron oxide nanoparticles

Polycyclic aromatic hydrocarbons (PAHs) are potentially hazardous compounds that could cause a severe impact on many ecosystems. They are very challenging to remove using conventional methods due to their hydrophobic nature. However, this issue can be resolved by utilizing surface-active molecules to increase their bioavailability. In this study, pyrene was chosen as the PAH compound to explore its degradability by the effect of individual bacterial strains (Pseudomonas stutzeri NA3 and Acinetobacter baumannii MN3) and mixed consortia (MC) along with natural surfactant derived from Sapindus mukorossi and iron oxide nanoparticles (NPs). Additionally, fatty acids esters, dipeptides, and sugar derivative groups were identified as potent bioactive components of natural surfactants. Various techniques, such as XRD, VSM, TEM, and FE-SEM with EDX, were utilized to characterize the pristine and Fenton-treated iron oxide NPs. The analytical results confirmed that the Fe3O4 crystal phase and spherical-shaped NPs exhibited excellent magnetic properties. The impact of natural surfactants and iron oxide NPs has significantly contributed to the biodegradation process, resulting in a prominent decrease in chemical oxygen demand (COD) levels. Gas chromatography-mass spectrometry (GC-MS) analysis showed that biodegradation systems produced primary hydrocarbon intermediates, which underwent oxidative degradation through Fenton treatment. Interestingly, synthesized iron oxide NPs effectively produced hydroxyl radical (•OH) during the Fenton reaction, which was confirmed by electron paramagnetic resonance (EPR) spectra, and the pristine iron oxide NPs underwent a material transformation observed. The study demonstrated an integrated approach for biodegradation and the Fenton reaction process to enhance the pyrene degradation efficiency (90%) compared to other systems. Using natural surfactants and iron oxide NPs in aquatic environments serves as a crucial platform at the interface of microorganisms and contaminated oil products. This interaction offers a promising solution for PAHs bioremediation.

Bacterial Biodegradation of Perfluorooctanoic Acid (PFOA) and Perfluorosulfonic Acid (PFOS) Using Pure Pseudomonas Strains

The principal objective of the present research involved the achievement of high biodegradation degrees of perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) using pure individual bacterial strains. The use of such microorganisms can contribute to the improvement of the wastewater treatment process in sewage treatment plants through bioaugmentation or other bioremediation processes. Thus, in this study, we investigated the biodegradation potential of PFOA and PFOS. Bacterial strains tested in this study were from the Pseudomonas genus, namely: Pseudomonas aeruginosa and Pseudomonas putida, due to their known capacity to degrade xenobiotic compounds. The results indicated that Pseudomonas aeruginosa was able to transform 27.9% of PFOA and 47.3% of PFOS in 96 h, while Pseudomonas putida managed to transform 19.0% of PFOA and 46.9% of PFOS in the same time frame. During the biodegradation tests, PFHxA was recognized as the principal biotransformation product of PFOA in the presence of Pseudomonas aeruginosa, and PFPeA, PFPxA and PFHpA were recognized as the biotransformation products in the presence of Pseudomonas putida. For PFOS, only two biotransformation products (PHHxA and PFHpA) were observed as a consequence of biodegradation by both bacterial strains.

Strain-level screening of human gut microbes identifies Blautia producta as a new anti-hyperlipidemic probiotic

ABSTRACT Compelling evidence has tightly linked gut microbiota with host metabolism homeostasis and inspired novel therapeutic potentials against metabolic diseases (e.g., hyperlipidemia). However, the regulatory profile of individual bacterial species and strain on lipid homeostasis remains largely unknown. Herein, we performed a large-scale screening of 2250 human gut bacterial strains (186 species) for the lipid-decreasing activity. Different strains in the same species usually displayed distinct lipid-modulatory actions, showing evident strain-specificity. Among the tested strains, Blautia producta exhibited the most potency to suppress cellular lipid accumulation and effectively ameliorated hyperlipidemia in high fat diet (HFD)-feeding mice. Taking a joint comparative approach of pharmacology, genomics and metabolomics, we identified an anteiso-fatty acid, 12-methylmyristic acid (12-MMA), as the key active metabolite of Bl. Producta. In vivo experiment confirmed that 12-MMA could exert potent hyperlipidemia-ameliorating efficacy and improve glucose metabolism via activating G protein-coupled receptor 120 (GPR120). Altogether, our work reveals a previously unreported large-scale lipid-modulatory profile of gut microbes at the strain level, emphasizes the strain-specific function of gut bacteria, and provides a possibility to develop microbial therapeutics against hyperlipidemia based on Bl. producta and its metabolite.

A rapid assay for assessing bacterial effects on Arabidopsis thermotolerance

BackgroundThe role of beneficial microbes in mitigating plant abiotic stress has received considerable attention. However, the lack of a reproducible and relatively high-throughput screen for microbial contributions to plant thermotolerance has greatly limited progress in this area, this slows the discovery of novel beneficial isolates and the processes by which they operate.ResultsWe designed a rapid phenotyping method to assess the effects of bacteria on plant host thermotolerance. After testing multiple growth conditions, a hydroponic system was selected and used to optimize an Arabidopsis heat shock regime and phenotypic evaluation. Arabidopsis seedlings germinated on a PTFE mesh disc were floated onto a 6-well plate containing liquid MS media, then subjected to heat shock at 45 °C for various duration. To characterize phenotype, plants were harvested after four days of recovery to measure chlorophyll content. The method was extended to include bacterial isolates and to quantify bacterial contributions to host plant thermotolerance. As an exemplar, the method was used to screen 25 strains of the plant growth promoting Variovorax spp. for enhanced plant thermotolerance. A follow-up study demonstrated the reproducibility of this assay and led to the discovery of a novel beneficial interaction.ConclusionsThis method enables rapid screening of individual bacterial strains for beneficial effects on host plant thermotolerance. The throughput and reproducibility of the system is ideal for testing many genetic variants of Arabidopsis and bacterial strains.

An eco-friendly approach to biosurfactant production using low-cost wastes

It is of great importance to reduce the production cost of biosurfactants, which have application areas in a wide range of industrial processes with their antimicrobial and anti-biofilm properties. Accordingly, it was aimed to determine the potent low-cost waste for the cost-effective biosurfactant production by environmental origin Bacillus sp. strains. 2% (v/v) of individual bacterial strain was inoculated into 50 mL of Bushnell Haas medium (pH:7.0) containing 8% (v/v) of each low-cost waste, 1% (w/v) yeast extract and 0.1% (v/v) trace element, and incubation period was carried out at 30 °C and 150 rpm for 7 days. Following the extraction of the culture supernatants, maximum biosurfactant yielded 0.139 ± 0.003 with potato wastewater by potent Bacillus subtilis MG847158.1. Hemolytic activity, 7.70 ± 0.35 mm zone diameter for oil displacement, 50.1 ± 0.8 emulsification index, 89.73 ± 0.9% bacterial adhesion, and decreasing of surface tension from 72.80 ± 0.1 mN/m to 23.97 ± 0.05 mN/m were also obtained. The extracted biosurfactant was further purified by silica gel column chromatography and characterized as lipopeptide by TLC, FT-IR, NMR, and SEM. In addition to being quite effective against both Gram-negative and Gram-positive bacteria, the highest antimicrobial and anti-biofilm activities of biosurfactant were against two Gram-negatives: E. coli (18.1 ± 0.8 mm) (MIC 1 mg mL−1, MBC 2 mg mL-1) and K. pneumoniae (97%) strains. To sum up, it is the first study to emphasize that the produced biosurfactant with low-cost potato wastewater can be used as an alternative to commercial antimicrobial agents.

Barotolerance of Acid-adapted and Cold-adapted Bacterial Isolates of E. coli O157:H7, Salmonella spp., and L. monocytogenes in an Acidic Buffer Model

The fruit and vegetable juice industry has shown a growing trend in minimally processed juices. A frequent technology used in the production of functional juices is cold pressure, which refers to the application of high pressure processing (HPP) at low temperatures to inactivate foodborne pathogens. HPP juice manufacturers are required to demonstrate a 5-log reduction of the pertinent microorganism to comply with FDA Juice HACCP. However, there is no consensus on validation study approaches for bacterial strain selection or their preparation. Individual bacterial strains were grown using three different growth conditions: neutral, cold-adapted, and acid-adapted. Approximately 6.0–7.0 log CFU/mL of the matrix-adapted bacterial strains were inoculated individually into buffered peptone water (BPW) at pH 3.50 ± 0.10 (HCl adjusted) and treated at sublethal pressures of 500 MPa for Escherichia coli O157:H7 and 200 MPa for Salmonella spp. and Listeria monocytogenes (180 s, 4°C). Analyses were conducted at 0, 24, and 48 h (4°C storage) post-HPP on nonselective media. E. coli O157:H7 exhibited greater barotolerance than Salmonella spp. and L. monocytogenes. In neutral growth conditions, E. coli O157:H7 strain TW14359 demonstrated the greatest resistance (2.94 ± 0.64 log reduction), and E. coli O157:H7 strain SEA13B88 was significantly more sensitive (P < 0.05). Salmonella isolates, neutral and acid-adapted, expressed similar barotolerance to one another. Cold-adapted S. Cubana and S. Montevideo showed greater resistance compared to other cold-adapted strains. Acid-adapted L. monocytogenes strain MAD328 had <1.00 ± 0.23 log reduction while acid-adapted L. monocytogenes strains CDC and Scott A were significantly more sensitive (P < 0.05) with reductions of 2.13 ± 0.48 and 3.43 ± 0.50 log CFU/mL, respectively. These results suggested, under the conditions tested, bacterial strain and preparation methods influence HPP efficacy and should be considered when conducting validation studies.

Enhanced Petroleum Removal by Potent Biosurfactant Producer Bacillus Subtilis CC9 Strain Isolated from an Oil Field

This study aimed to enhance the removal of petroleum with potent biosurfactant producing bacterial strains (Bacillius subtilis CC9, Enterobacter asburiae WMB1, Klebsiella oxytoca Rizhao 536-1, and Acinetobacter pittii PgBE252) isolated from an oil field. The biosurfactant production was determined by different screening methods such as hemolytic activity, drop-collapse, oil spreading, BATH, emulsification index and surface tension. While the presence of biosurfactant was detected with individual bacterial strain, B. subtilis CC9 strain was found to be quite effective on petroleum degradation (92%) with a high yield of biosurfactant production (0.95 ±0.05 g L-1). The degradation rate constant and half-life period of B. subtilis CC9 strain were calculated as K = 2.533 day−1, t1/2 = 0.273. It has been clearly shown with GC/MS analysis that B. subtilis CC9 strain was effective on the removal of long chain n-alkanes (C31 - C35) as well as short and medium chains. The FT-IR analysis also approved the presence of aliphatic and peptide moieties of biosurfactant extracted from B. subtilis CC9 strain. It is remarkably pointed out with this study that high yield of biosurfactant producing B. subtilis CC9 strain can be used in advanced petroleum bioremediation studies as an alternative to chemical surfactants.

Species-specific CD4+ T cells enable prediction of mucosal immune phenotypes from microbiota composition

How bacterial strains within a complex human microbiota collectively shape intestinal T cell homeostasis is not well understood. Methods that quickly identify effector strains or species that drive specific mucosal T cell phenotypes are needed to define general principles for how the microbiota modulates host immunity. We colonize germ-free mice with defined communities of cultured strains and profile antigen-specific responses directed toward individual strains exvivo. We find that lamina propria T cells are specific to bacterial strains at the species level and can discriminate between strains of the same species. Exvivo restimulations consistently identify the strains within complex communities that induce Th17 responses invivo, providing the potential to shape baseline immune tone via community composition. Using an adoptive transfer model of colitis, we find that lamina propria T cells respond to different bacterial strains in conditions of inflammation versus homeostasis. Collectively, our approach represents a unique method for efficiently predicting the relative impact of individual bacterial strains within a complex community and for parsing microbiota-dependent phenotypes into component fractions.

An improved method for corn stalk in-situ degrading synthetic bacterial consortium construction in a cold region of China

A cornstalk-degrading bacterial consortium was constructed from a cold region of China. Soil and cornstalks samples were screened using lignin or cellulose as sole carbon source to obtain individual bacterial strains. Additionally, a bottom-up strategy was used to construct a bacterial consortium composed of six strains with a synergistic enzymatic pattern, resulting in a cornstalk weight loss of 43.62%, which was 15.08 percentage points higher than the control. Lignin, cellulose, and hemicellulose components of cornstalk, respectively, lost 52.40%, 41.24%, and 45.97% of their weight at 15 °C soil conditions and within a 40 days period. This was significantly higher than the control treatment, especially for the lignin component. The consortium was composed of Bacillus subtilis, Pseudomonas sp., Citrobacter portucalensis, B. thuringiensis, P. putida, Acinetobacter lwoffii.