Plasmonic Colloidosome-Based Multifunctional Platform for Bacterial Identification and Antimicrobial Resistance Detection.

Antimicrobial resistance (AMR) is an urgent threat to public health. Rapid bacterial identification and AMR tests are important to promote personalized treatment of patients and to limit the spread of AMR. Herein, we explore the utility of plasmonic colloidosomes in bacterial analysis based on mass spectrometry (MS) and Raman scattering. It is found that colloidosomes can provide a rigid micrometer-size platform for bacterial culture and analysis. Coupled with matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS, this platform enables bacterial identification at the species level with cell counts as low as 50, >100 times more sensitive than the standard method of MALDI-TOF MS based bacterial identification. Coupled with Raman scattering, it can distinguish single bacterial cells at the strain level and recognize AMR at the single-cell level. These reveal the broad potential of the platform for flexible and versatile bacterial detection and typing.

Application of independent immobilization in benzo[a]pyrene biodegradation by synthetic microbial consortium.

Bioaugmentation is an effective approach to remove the benzo[a]pyrene (BaP) from the environment, while its effect depends on the functional stability of the inoculated microorganisms. The aim of this study is to develop an approach on reducing the mutual exclusion of bacteria in the synthetic consortium in BaP degradation. Eight BaP-degrading bacterial strains were isolated from an enrichment with BaP as the sole carbon source. Two strains of Cupriavidus spp. exhibited greater degradation capacity (3.02-3.30 mg L-1 day-1) and selected as the "good degraders" in the synthetic consortia. Because of the mutual exclusion, the BaP-degradation capacity was reduced (1.47-1.77 mg L-1 day-1) when the other strains were added into "good degraders" through directly mixing the inocula. This mutual exclusion was mitigated through independent immobilization, in which the strains were embedded in sodium alginate before constructing the consortium. The consortium constructed by independent immobilization exhibited comparable BaP-degradation capacity with the high efficient strains. Therefore, the independent immobilization can be an advanced approach in functional consortium synthesis.

Simultaneous biodegradation of phenol and cyanide present in coke-oven effluent using immobilized Pseudomonas putida and Pseudomonas stutzeri

ABSTRACT Discharge of coke-oven wastewater to the environment may cause severe contamination to it and also threaten the flora and fauna, including human beings. Hence before dumping it is necessary to treat this dangerous effluent in order to minimize the damage to the environment. Conventional technologies have inherent drawbacks however, biological treatment is an advantageous alternative method. In the present study, bacteria were isolated from the soil collected from the sites contaminated by coke-oven effluent rich in phenol and cyanide. Nucleotides sequence alignment and phylogenetic analysis showed the identity of the selected phenol and cyanide degrading isolates NAUN-16 and NAUN-1B as Pseudomonas putida and Pseudomonas stutzeri, respectively. These two isolates tolerated phenol up to 1800 mg L-1 and cyanide up to 340 mg L-1 concentrations. The isolates were immobilized on activated charcoal, saw dust and fly ash. The effluent was passed through the column packed with immobilized cells with a flow rate of 5 mL min-1. The isolates showed degradation of phenol up to 80.5% and cyanide up to 80.6% and also had the ability to reduce biological oxygen demand, chemical oxygen demand and lower the pH of effluent from alkaline to near neutral. The study suggests the utilization of such potential bacterial strains in treating industrial effluent containing phenol and cyanide, before being thrown in any ecosystem.

Simultaneous biodegradation of phenol and cyanide present in coke-oven effluent using immobilized Pseudomonas putida and Pseudomonas stutzeri.

Discharge of coke-oven wastewater to the environment may cause severe contamination to it and also threaten the flora and fauna, including human beings. Hence before dumping it is necessary to treat this dangerous effluent in order to minimize the damage to the environment. Conventional technologies have inherent drawbacks however, biological treatment is an advantageous alternative method. In the present study, bacteria were isolated from the soil collected from the sites contaminated by coke-oven effluent rich in phenol and cyanide. Nucleotides sequence alignment and phylogenetic analysis showed the identity of the selected phenol and cyanide degrading isolates NAUN-16 and NAUN-1B as Pseudomonas putida and Pseudomonas stutzeri, respectively. These two isolates tolerated phenol up to 1800mgL-1 and cyanide up to 340mgL-1 concentrations. The isolates were immobilized on activated charcoal, saw dust and fly ash. The effluent was passed through the column packed with immobilized cells with a flow rate of 5mLmin-1. The isolates showed degradation of phenol up to 80.5% and cyanide up to 80.6% and also had the ability to reduce biological oxygen demand, chemical oxygen demand and lower the pH of effluent from alkaline to near neutral. The study suggests the utilization of such potential bacterial strains in treating industrial effluent containing phenol and cyanide, before being thrown in any ecosystem.

[Effects of immobilization on community structure and function of sulfide oxidizing microbiota].

Objective: To study the effects of cell immobilization on sulfide degradation ability and microbial community structure. Methods: Sulfide oxidizing microbiota was immobilized by entrapment on polyvinyl alcoholsodium alginate-activated carbon carrier. Sulfide degradation ability of the immobilized and free sulfide oxidizing microbiota was compared in sulfide-rich minimal medium. PCR-DGGE technique was used to reveal the effects of immobilization on microbial community structure. Results: The maximum sulfide degradation ability of the sulfide oxidizing microbiota in 12 h decreased from 1000 to 600 mg/L after immobilization. Community structure of the sulfide oxidizing microbiota changed after immobilization, but Catenococcus thiocycli was little affected. Thioclava pacifica was even strengthened in the microbiota after immobilization and sulfide degrading. Conclusion: In conclusion, limited by substrate diffusion and transfer in carrier material, sulfide degradation ability of the sulfide oxidizing microbiota under high sulfide concentration decreased after immobilization. Also, immobilization could affect the microbial community structure of sulfide oxidizing microbiota due to different adaptation ability to the microenvironment and adhesion ability to the carrier material.

Simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. after their exposure to petroleum hydrocarbons.

A method of simultaneous species-specific PCR detection and viability testing of poly(vinyl alcohol) cryogel-entrapped Rhodococcus spp. was developed that allowed the estimation of immobilized Rhodococcus opacus and Rhodococcus ruber survival after their exposure to petroleum hydrocarbon mixture. Spectrophotometric INT assay revealed high tolerance of gel-immobilized rhodococci to petroleum hydrocarbons, while among two Rhodococcus strains studied, R. ruber tolerated better to hydrocarbons compared to R. opacus. These findings were confirmed by respirometry results that showed increased respiratory activity of gel-immobilized Rhodococcus strains after 10-day incubation with 3% (v/v) petroleum hydrocarbon mixture. Moreover, jointly incubated rhodococcal strains demonstrated higher oxidative activities toward petroleum hydrocarbons than individual strains. Both Rhodococcus species were recovered successfully in cryogel granules using 16S rDNA-targeted PCR, even though the granules were previously stained with INT and extracted with ethanol. The method developed can be used for rapid detection and monitoring of gel-immobilized bacterial inocula in bioreactors or contaminated soil systems.

Activated zeolite--suitable carriers for microorganisms in anaerobic digestion processes?

Plant cell wall structures represent a barrier in the biodegradation process to produce biogas for combustion and energy production. Consequently, approaches concerning a more efficient de-polymerisation of cellulose and hemicellulose to monomeric sugars are required. Here, we show that natural activated zeolites (i.e. trace metal activated zeolites) represent eminently suitable mineral microhabitats and potential carriers for immobilisation of microorganisms responsible for anaerobic hydrolysis of biopolymers stabilising related bacterial and methanogenic communities. A strategy for comprehensive analysis of immobilised anaerobic populations was developed that includes the visualisation of biofilm formation via scanning electron microscopy and confocal laser scanning microscopy, community and fingerprint analysis as well as enzyme activity and identification analyses. Using SDS polyacrylamide gel electrophoresis, hydrolytical active protein bands were traced by congo red staining. Liquid chromatography/mass spectroscopy revealed cellulolytical endo- and exoglucanase (exocellobiohydrolase) as well as hemicellulolytical xylanase/mannase after proteolytic digestion. Relations to hydrolytic/fermentative zeolite colonisers were obtained by using single-strand conformation polymorphism analysis (SSCP) based on amplification of bacterial and archaeal 16S rRNA fragments. Thereby, dominant colonisers were affiliated to the genera Clostridium, Pseudomonas and Methanoculleus. The specific immobilisation on natural zeolites with functional microbes already colonising naturally during the fermentation offers a strategy to systematically supply the biogas formation process responsive to population dynamics and process requirements.

Bioaugmentation of UASB reactors with immobilized Sulfurospirillum barnesii for simultaneous selenate and nitrate removal.

Whole-cell immobilization of selenate-respiring Sulfurospirillum barnesii in polyacrylamide gels was investigated to allow the treatment of selenate contaminated (790 microg Se x L(-1)) synthetic wastewater with a high molar excess of nitrate (1,500 times) and sulfate (200 times). Gel-immobilized S. barnesii cells were used to inoculate a mesophilic (30 degrees C) bioreactor fed with lactate as electron donor at an organic loading rate of 5 g chemical oxygen demand (COD) x L(-1) day(-1). Selenate was reduced efficiently (>97%) in the nitrate and sulfate fed bioreactor, and a minimal effluent concentration of 39 microg Se x L(-1) was obtained. Scanning electron microscopy with energy dispersive X-ray (SEM-EDX) analysis revealed spherical bioprecipitates of

Enhanced hydantoinase and N-carbamoylase activity on immobilisation of Agrobacterium tumefaciens.

Cell extracts of Agrobacterium tumefaciens, immobilised in calcium alginate beads, had a 7-fold increase in N-carbamoylase (N-carbamylamino acid amidohydrolase E.C. 3.5.1) activity on reaction with N-carbamylglycine. The hydantoinase (dihydropyrimidinase E.C. 3.5.2.2) and N-carbamoylase activities remained stable over 4 weeks storage at 4 degrees C relative to the non-immobilised enzymes, with the hydantoinase activity showing a 5-fold increase in activity relative to the non-immobilised hydantoinase. The pH optima of the immobilised hydantoinase and N-carbamoylase enzymes decreased to pH 7 and pH 8, respectively. The temperature optimum remained at 40 degrees C for the N-carbamoylase enzyme while the hydantoinase activity was optimal at 50 degrees C.

Biooxidation of ferrous iron by immobilized Acidithiobacillus ferrooxidans in poly(vinyl alcohol) cryogel carriers.

PVA-cryogels entrapping about 10(9) cells of Acidithiobacillus ferrooxidans per ml of gel were prepared by freezing-thawing procedure, and the biooxidation of Fe2+ by immobilized cells was investigated in a 0.365 l packed-bed bioreactor. Fe2+ oxidation fits a plug-flow reaction model well. A maximum oxidation rate of 3.1 g Fe2+ l(-1) h(-1) was achieved at the dilution rate of 0.4 h(-1) or higher, while no obvious precipitate was determined at this time. In addition, cell-immobilized PVA-cryogels packed in bioreactor maintained their oxidative ability for more than two months under non-sterile conditions.

Asymmetric synthesis with immobilized yeast in organic solvents: equilibrium conversion and effect of reactant partitioning on whole cell biocatalysis.

A newly isolated strain of the yeast Saccharomyces cerevisiae is investigated for the biocatalytic reduction of ketones and the oxidation of alcohols in organic solvents. The yeast cells are immobilized by entrapment within calcium alginate beads and are found to possess the ability to stereoselectively reduce prochiral ketones and oxidize chiral alcohols to equilibrium conversions. The effect of reactant partitioning on the initial rate of the reactions is also investigated. The observed initial rates are found to vary inversely with reactant partitioning between the organic solvent and the biocatalyst beads. A kinetic model is developed to describe the initial reaction rate of hexanone reduction as a function of substrate concentration within the alginate beads.