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1.
Huan Jing Ke Xue ; 40(7): 3126-3134, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854710

RESUMO

Application of microalgae in wastewater treatment is regarded as a potential green technology. However, its engineering application has been largely hindered because of the difficulty of biomass separation and harvesting. This study aimed to identify the key parameters influencing the process of microalgae immobilization. To do this, the study focused on immobilization technology and Scenedesmus obliquus, and employed the response surface methodology (RSM) and the Box-Behnken design (BBD). In an evaluation of the performance of microalgae beads, the fixing agent concentration, the cross-linking agent concentration, and the cross-linking time were selected as the independent variables, and the mechanical strength, the mass transfer rate, and the growth rate of immobilized microalgae beads were the response values. The optimal conditions and the uptake potential of the microalgae beads with respect to ammonia nitrogen (NH4+-N) were further explored and analyzed. The results showed that the optimal parameters for the preparation of immobilized microalgae beads were 5%, 2%, and 16 h, and the maximum removal capacity was obtained using mixotrophic cultivation with an embedding density of 1×106 cells·mL-1 and an organic matter concentration of 300 mg·L-1. In addition, the removal capacity of immobilized microalgae with respect to high concentrations of NH4+-N was significantly higher than for free-living microalgae. When the initial concentrations of NH4+-N were approximately 50 and 70 mg·L-1, NH4+-N was removed by the immobilized microalgae (after a 5-day mixotrophic cultivation) at a rate of (96.6±0.1)% and (65.2±4.5)%, respectively. With an initial NH4+-N concentration of 30 mg·L-1, the dominance of free-living microalgae was clear, with a removal rate of (97.8±0.6)% after a 3-day cultivation. However, under heterotrophic cultivation, the removal rate of NH4+-N by immobilized microalgae was generally low and gradually decreased with increasing concentrations. When the initial concentration was approximately 30 mg·L-1, the removal rate was only (49.0±3.1)%. This study provides new prospects for sustainable urban wastewater treatment, a new approach for resource recycling, and a strong theoretical foundation for the popularization and application of microalgae in wastewater treatment.


Assuntos
Amônia/isolamento & purificação , Microalgas/metabolismo , Nitrogênio/isolamento & purificação , Águas Residuárias , Purificação da Água/métodos , Biomassa , Células Imobilizadas/metabolismo
2.
Appl Microbiol Biotechnol ; 103(21-22): 8923-8935, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31520132

RESUMO

UV and gamma irradiation mutagenesis was applied on Aspergillus fumigatus and Alternaria tenuissima in order to improve their producing ability of paclitaxel. Among the screened mutants, two stable strains (designated TXD105-GM6 and TER995-GM3) showed the maximum paclitaxel production. Paclitaxel titers of the two respective mutants were dramatically intensified to 1.22- and 1.24-fold, as compared by their respective parents. Immobilization using five different entrapment carriers of calcium alginate, agar-agar, Na-CMC, gelatin, and Arabic gum was successfully applied for production enhancement of paclitaxel by the two mutants. The immobilized cultures were superior to free-cell cultures and paclitaxel production by the immobilized mycelia was much higher than that of the immobilized spores using all the tried carriers. Moreover, calcium alginate gel beads were found the most conductive and proper entrapment carrier for maximum production of paclitaxel. The feasibility of the paclitaxel production by the immobilized mycelia as affected by incubation period, medium volume, and number of beads per flask was adopted. Under the favorable immobilization conditions, the paclitaxel titers were significantly intensified to 1.31- and 1.88-fold by the respective mutants, as compared by their free cultures. The obtained paclitaxel titers by the immobilized mycelia of the respective mutants (694.67 and 388.65 µg L-1) were found promising in terms of fungal production of paclitaxel. Hence, these findings indicate the future possibility to reduce the cost of producing paclitaxel and suggest application of the immobilization technique for the biotechnological production of paclitaxel at an industrial scale.


Assuntos
Alternaria/metabolismo , Antineoplásicos/metabolismo , Aspergillus fumigatus/metabolismo , Paclitaxel/biossíntese , Alginatos/química , Alternaria/química , Alternaria/genética , Aspergillus fumigatus/química , Aspergillus fumigatus/genética , Células Imobilizadas/química , Células Imobilizadas/metabolismo , Fermentação , Microbiologia Industrial , Micélio/química , Micélio/genética , Micélio/metabolismo
3.
Nat Commun ; 10(1): 3656, 2019 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-31409793

RESUMO

In this work we model the glomerular filtration barrier, the structure responsible for filtering the blood and preventing the loss of proteins, using human podocytes and glomerular endothelial cells seeded into microfluidic chips. In long-term cultures, cells maintain their morphology, form capillary-like structures and express slit diaphragm proteins. This system recapitulates functions and structure of the glomerulus, including permselectivity. When exposed to sera from patients with anti-podocyte autoantibodies, the chips show albuminuria proportional to patients' proteinuria, phenomenon not observed with sera from healthy controls or individuals with primary podocyte defects. We also show its applicability for renal disease modeling and drug testing. A total of 2000 independent chips were analyzed, supporting high reproducibility and validation of the system for high-throughput screening of therapeutic compounds. The study of the patho-physiology of the glomerulus and identification of therapeutic targets are also feasible using this chip.


Assuntos
Glomérulos Renais/metabolismo , Dispositivos Lab-On-A-Chip , Nefrite Hereditária/metabolismo , Albuminas/metabolismo , Albuminúria/tratamento farmacológico , Albuminúria/metabolismo , Células Imobilizadas/química , Células Imobilizadas/metabolismo , Células Endoteliais/química , Células Endoteliais/metabolismo , Humanos , Glomérulos Renais/química , Glomérulos Renais/efeitos dos fármacos , Masculino , Nefrite Hereditária/tratamento farmacológico , Podócitos/química , Podócitos/metabolismo
4.
Biosens Bioelectron ; 142: 111571, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445395

RESUMO

The extracellular electron transfer of Shewanella oneidensis MR-1 (MR-1) has been extensively studied due to the importance of the biosensors and energy applications of bioelectrochemical systems. However, the oxidation of metal compounds by MR-1, which represents the inward extracellular electron transfer from extracellular electron donors into the microbe, is barely understood. In this study, MR-1 immobilized on an electrode electrocatalyzes the oxidation of [Fe(CN)6]4- to [Fe(CN)6]3- efficiently and selectively. The selectivity depends on midpoint potential and overall charge(s) of redox molecules. Among 12 investigated redox molecules, the negatively charged molecules with high midpoint potentials, i.e., [Ru(CN)6]4- and [Fe(CN)6]4-, show strong electrocatalysis. Neither reference bacteria (Escherichia coli K-12 nor Streptococcus mutans) electrocatalyze the oxidation of [Fe(CN)6]4-. The electrocatalysis decays when MR-1 is covered with palladium nanoparticles presumptively involved with cytochromes c. However, cytochromes c MtrC and OmcA on MR-1 do not play an essential role in this process. The results support a model that [Fe(CN)6]4- donor electrons to MR-1 by interacting with undiscovered active sites and the electrons are subsequently transferred to the electrode through the mediating effect of [Fe(CN)6]4-/3-. The selective electron uptake by MR-1 provides valuable and fundamental insights of the applications of bioelectrochemical systems and the detection of specific redox molecules.


Assuntos
Ferrocianetos/metabolismo , Metais/metabolismo , Shewanella/metabolismo , Técnicas Biossensoriais , Catálise , Células Imobilizadas/metabolismo , Técnicas Eletroquímicas , Eletrodos , Transporte de Elétrons , Elétrons , Nanopartículas/metabolismo , Nanopartículas/ultraestrutura , Oxirredução , Paládio/metabolismo
5.
ACS Appl Mater Interfaces ; 11(34): 30585-30595, 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31378063

RESUMO

One of the challenges for extrusion bioprinting using low-viscosity bioinks is the fast gravity-driven sedimentation of cells. Cells in a hydrogel bioink that features low viscosity tend to settle to the bottom of the bioink reservoir, and as such, their bioprintability is hindered by association with the inhomogeneous cellularized structures that are deposited. This is particularly true in cases where longer periods are required to print complex or larger tissue constructs. Increasing the bioink's viscosity efficiently retards sedimentation but gives rise to cell membranolysis or functional disruption due to increased shear stress on the cells during the extrusion process. Inspired by the rainbow cocktail, we report the development of a multilayered modification strategy for gelatin methacryloyl (GelMA) bioink to manipulate multiple liquid interfaces, providing interfacial retention to retard cell sedimentation in the bioink reservoir. Indeed, the interfacial tension in our layer-by-layer bioink system, characterized by the pendant drop method, was found to be exponentially higher than the sedimental pull (ΔGravity-Buoyancy = ∼10-9 N) of cells, indicating that the interfacial retention is crucial for preventing cell sedimentation across the adjacent layers. It was demonstrated that the encapsulated cells displayed better dispersibility in constructs bioprinted using the multilayered GelMA bioink system than that of pristine GelMA where the index of homogeneity of the cell distribution in the multilayered bioink was 4 times that of the latter.


Assuntos
Células Imobilizadas/metabolismo , Hidrogéis/química , Tinta , Animais , Bioimpressão , Células Imobilizadas/citologia , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Células NIH 3T3
6.
Mater Sci Eng C Mater Biol Appl ; 103: 109835, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31349495

RESUMO

Hydrogels are promising soft materials for the delivery of therapeutic cells and cargo molecules. Inspired by mussel adhesion chemistry, hydrogels based on catechol (Cat)-modified polysaccharides have been developed to enhance hydrogel-tissue interactions. However, due to the inevitable side reactions such as self-polymerization of dopamine involved in the conventional catechol conjugation process, the efficiency of catechol conjugation to polymers is typically low, leading to insufficient stability, low mechanical strength, and poor adhesiveness of these catechol-modified hydrogels. In this study, we report a new approach to synthesize catechol-functionalized hyaluronic acid with improved degree of substitution. Due to the significantly increased conjugated Cat groups, the obtained HA-Cat hydrogels not only can adhere to tissue samples under wet conditions but also can capture cell adhesion proteins to enhance cell attachment and spreading. Meanwhile, owing to the extensive Cat-protein interactions, these hydrogels can also facilitate long-term release of protein-based therapeutic cargoes, such as the osteoinductive BMP-2 protein, thereby effectively promoting osteogenic differentiation of stem cells. These findings show that the HA-Cat hydrogels are ideal carriers of therapeutic cells and drugs for tissue regeneration.


Assuntos
Catecóis/química , Adesão Celular , Células Imobilizadas/metabolismo , Hidrogéis/química , Células-Tronco Mesenquimais/metabolismo , Células Imobilizadas/citologia , Humanos , Células-Tronco Mesenquimais/citologia
7.
Nat Commun ; 10(1): 2946, 2019 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-31270421

RESUMO

The capability to encapsulate designated live cells into a biologically and mechanically tunable polymer layer is in high demand. Here, an approach to weave functional DNA polymer cocoons has been proposed as an encapsulation method. By developing in situ DNA-oriented polymerization (isDOP), we demonstrate a localized, programmable, and biocompatible encapsulation approach to graft DNA polymers onto live cells. Further guided by two mutually aided enzymatic reactions, the grafted DNA polymers are assembled into DNA polymer cocoons at the cell surface. Therefore, the coating of bacteria, yeast, and mammalian cells has been achieved. The capabilities of this approach may offer significant opportunities to engineer cell surfaces and enable the precise manipulation of the encapsulated cells, such as encoding, handling, and sorting, for many biomedical applications.


Assuntos
Células Imobilizadas/citologia , DNA/química , Polímeros/química , Membrana Celular/metabolismo , Sobrevivência Celular , Células Imobilizadas/metabolismo , Humanos , Células MCF-7 , Polimerização
8.
Biosens Bioelectron ; 141: 111435, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31238280

RESUMO

Existing at the interface of biology and electronics, living cells have been in use as biorecognition elements (bioreceptors) in biosensors since the early 1970s. They are an interesting choice of bioreceptors as they allow flexibility in determining the sensing strategy, are cheaper than purified enzymes and antibodies and make the fabrication relatively simple and cost-effective. And with advances in the field of synthetic biology, microfluidics and lithography, many exciting developments have been made in the design of cell-based biosensors in the last about five years. 3D cell culture systems integrated with electrodes are now providing new insights into disease pathogenesis and physiology, while cardiomyocyte-integrated microelectrode array (MEA) technology is set to be standardized for the assessment of drug-induced cardiac toxicity. From cell microarrays for high-throughput applications to plasmonic devices for anti-microbial susceptibility testing and advent of microbial fuel cell biosensors, cell-based biosensors have evolved from being mere tools for detection of specific analytes to multi-parametric devices for real time monitoring and assessment. However, despite these advancements, challenges such as regeneration and storage life, heterogeneity in cell populations, high interference and high costs due to accessory instrumentation need to be addressed before the full potential of cell-based biosensors can be realized at a larger scale. This review summarizes results of the studies that have been conducted in the last five years toward the fabrication of cell-based biosensors for different applications with a comprehensive discussion on the challenges, future trends, and potential inputs needed for improving them.


Assuntos
Técnicas Biossensoriais/instrumentação , Técnicas de Cultura de Células/instrumentação , Técnicas Analíticas Microfluídicas/instrumentação , Animais , Técnicas Biossensoriais/métodos , Técnicas de Cultura de Células/métodos , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Avaliação Pré-Clínica de Medicamentos/instrumentação , Avaliação Pré-Clínica de Medicamentos/métodos , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Desenho de Equipamento , Humanos , Técnicas Analíticas Microfluídicas/métodos
9.
Enzyme Microb Technol ; 128: 72-78, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31186113

RESUMO

Glutaric acid is an attractive C5 dicarboxylic acid with wide applications in the biochemical industry. Glutaric acid can be produced by fermentation and bioconversion, and several of its biosynthesis pathways have been well characterized, especially the simple pathway involving glutaric acid from l-lysine using 5-aminovaleric acid. We previously reported the production of glutaric acid using 5-aminovaleric acid and α-ketoglutaric acid by a whole-cell reaction, resulting in a high conversion yield. In this study, we sought to enhance the stability and reusability of this whole-cell system for realizing the efficient production of glutaric acid under harsh reaction conditions. To this end, various matrices were screened to immobilize Escherichia coli whole-cell overexpressing 4-aminobutyrate aminotransferase (GabT), succinate semi-aldehyde dehydrogenase (GabD), and NAD(P)H oxidase (NOX). We ultimately selected a PVA-PEG gel (LentiKats®) for cell entrapment, and several factors of the reaction were optimized. The optimal temperature and pH were 35 °C and 8.5, respectively. Treatment with Tween 80 as a surfactant, as well as additional NOX, was found to be effective. Under the optimized conditions, an immobilized cell retained 55% of its initial activity even after the eighth cycle, achieving 995.2 mM accumulated glutaric acid, whereas free cell lost most of their activity after only two cycles. This optimized whole-cell system can be used in the large-scale production of glutaric acid.


Assuntos
Aminoácidos Neutros/metabolismo , Células Imobilizadas/metabolismo , Escherichia coli/metabolismo , Glutaratos/metabolismo , Biotransformação , Escherichia coli/enzimologia , Géis , Concentração de Íons de Hidrogênio , Polietilenoglicóis , Álcool de Polivinil , Temperatura Ambiente
10.
J Biosci Bioeng ; 128(5): 544-550, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31208800

RESUMO

Acinetobacter sp. Tol 5 exhibits an autoagglutinating nature and high adhesiveness to various abiotic surfaces through its bacterionanofiber protein AtaA. We have developed new bacterial immobilization methods utilizing the high adhesiveness of AtaA. We previously reported that salt is essential for the adhesiveness of AtaA. In the current study, we unexpectedly found that Tol 5 cells were not immobilized onto polyurethane foam support during growth in LB medium although AtaA was properly expressed and displayed onto the cell surface. The adhesion of Tol 5 resting cells was not affected by sugars but drastically inhibited by yeast extract and casein hydrolysates such as tryptone and casamino acids technical grade (CA-T). Some amino acids, which are major components of CA-T, partially inhibited the adhesion of Tol 5 cells. Experimental results suggested that oligopeptides might effectively inhibit the cell adhesion. Immobilized cells onto the support through AtaA were detached in CA-T solution. Also, the detached cells could be re-immobilized onto the support without impairing of their adhesiveness by replacing CA-T solution to a basal salt medium. Microscopic observation revealed that breaking of AtaA-mediated cell-cell interaction is important for the detachment of Tol 5 cells from the support. CA-T also inhibited AtaA-mediated autoagglutination and dispersed cell clumps through AtaA. This is the first report on adhesion inhibitors against AtaA and suggests that casein hydrolysates like CA-T would be a powerful tool for controlling AtaA-mediated bacterial immobilization.


Assuntos
Caseínas/metabolismo , Oligopeptídeos/metabolismo , Acinetobacter/metabolismo , Células Imobilizadas/metabolismo
11.
Appl Biochem Biotechnol ; 189(4): 1209-1222, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31228002

RESUMO

The foremost aim of the present study was to enhance butanol production in an extractive fermentation study in presence of non-ionic surfactant using immobilized cells. Earlier studies had shown improved butanol production with non-ionic surfactant and immobilized cells independently. Therefore, in the present work, the combined effect of extractive fermentation and immobilized cells on butanol production was studied. Different matrices (brick, bamboo, cotton fiber, flannel cloth, and polyurethane foam) were tested for immobilization of Clostridium sporogenes. Immobilized biomass thus obtained was used in an extractive fermentation study with non-ionic surfactant L62. Biomass immobilized on polyurethane foam (PF) doubled the butanol production in presence of 6% (v/v) L62 with respect to control (free cells without surfactant). Further, the effect of different carbon sources was also studied to check the suitability of different industrial wastes containing different carbon sources. Glucose was found to be the best carbon source.


Assuntos
Butanóis/metabolismo , Células Imobilizadas/metabolismo , Clostridium/genética , Tensoativos/química , Águas Residuárias/química , Poliuretanos/química , Águas Residuárias/microbiologia
12.
Appl Biochem Biotechnol ; 189(2): 448-458, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31044370

RESUMO

For efficiently enhancing the activity of isoeugenol monooxygenase, a whole cell overproducing active aggregate IEM720-18A was successfully fabricated via the fusion of amphiphilic short peptide 18A (EWLKAFYEKVLEKLKELF) and isoeugenol monooxygenase and then efficiently expressed in E. coli BL21 (DE3). Such resulting bacteria, E. coli BL21 (DE3) harboring pET30a-IEM720-18A was applied in the biotransformation of isoeugenol to vanillin with the optimization of cultivation conditions. Our results revealed that the vanillin concentration reached to the highest level (14.5 mmol/L) under the optimized reaction conditions including 1.5-g cells containing active aggregate of IEM720-18A, 10% (v/v) dimethyl sulfoxide (DMSO), 100 mmol/L isoeugenol, 50 mmol/L glycine-sodium hydroxide buffer (pH 10.5) in 10 mL reaction volume, and 200 rpm at 25 °C for 36 h. Moreover, the active aggregate IEM720-18A was immobilized with 100 mmol/L glutaraldehyde at 4 °C to improve the operational stability. The highest activity could be achieved when the reactions were carried out at 25 °C and the relative activity of the immobilized enzyme maintained over 60% after seven recycles. Our study provides a new approach to the biotransformation of isoeugenol into vanillin.


Assuntos
Benzaldeídos/metabolismo , Células Imobilizadas/metabolismo , Escherichia coli/metabolismo , Eugenol/análogos & derivados , Escherichia coli/genética , Eugenol/metabolismo
13.
ACS Appl Mater Interfaces ; 11(21): 18968-18977, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31046215

RESUMO

A viable approach for methanol production under ambient physiological conditions is to use greenhouse gases, methane (CH4) and carbon dioxide (CO2), as feed for immobilized methanotrophs. In the present study, unique macroporous carbon particles with pore sizes in the range of ∼1-6 µm were synthesized and used as support for the immobilization of Methylocella tundrae. Immobilization was accomplished covalently on hierarchical macroporous carbon particles. Maximal cell loading of covalently immobilized M. tundrae was 205 mgDCM g-1 of particles. Among these particles, the cells immobilized on 3.6 µm pore size particles showed the highest reusability with the least leaching and were chosen for further study. After immobilization, M. tundrae showed up to 2.4-fold higher methanol production stability at various pH and temperature values because of higher stability and metabolic activity than free cells. After eight cycles of reuse, the immobilized cells retained 18.1-fold higher relative production stability compared to free cells. Free and immobilized cells exhibited cumulative methanol production of 5.2 and 9.5 µmol mgDCM-1 under repeated batch conditions using simulated biogas [CH4 and CO2, 4:1 (v/v)] as feed, respectively. The appropriate pore size of macroporous particles favors the efficient M. tundrae immobilization to retain better biocatalytic properties. This is the first report concerning the covalent immobilization of methanotrophs on the newly synthesized macroporous carbon particles and its subsequent application in repeated methanol production using simulated biogas as a feed.


Assuntos
Biotecnologia/métodos , Células Imobilizadas/metabolismo , Gases de Efeito Estufa/análise , Metanol/análise , Bactérias/citologia , Biocombustíveis/análise , Carbono/química , Metano/análise , Porosidade
14.
IET Nanobiotechnol ; 13(2): 144-149, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31051444

RESUMO

Azo dyes are widely used in industries and their release in the environment contributes to the pollution of effluents. The authors aim to develop a new eco-friendly water treatment method for the degradation of azo dyes based on in situ magnetic separation and immobilisation of bacterial cells. The immobilisation was achieved using superparamagnetic Fe3O4 nanoparticles and offers the possibility of reusing bacteria by magnetic separation for several degradation cycles. The iron-oxide nanoparticles were synthesised by reverse co-precipitation. The Gram-positive bacteria Bacillus subtilis were immobilised using iron-oxide nanoparticles by adsorption and then separated with an external magnetic field. Transmission electron microscopy observation showed that the particles' diameter was ∼20 nm with a narrow size distribution. Moreover, the iron-oxide nanoparticles were adsorbed onto the surface in order to coat the cells. B. subtilis has proved its ability to decolorise and degrade several azo dyes at different values of pH, with the highest decolorisation rate for Congo red. Furthermore, immobilised cells have a degradation activity similar to that of free cells. The system provided a degradation rate up to 80% and could be reused for seven batch cycles.


Assuntos
Compostos Azo/metabolismo , Bacillus subtilis , Células Imobilizadas , Nanopartículas de Magnetita/química , Purificação da Água/métodos , Compostos Azo/análise , Bacillus subtilis/citologia , Bacillus subtilis/metabolismo , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Química Verde/métodos
15.
Ecotoxicol Environ Saf ; 180: 317-325, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31100595

RESUMO

Biodegradation of phenolic compounds in wastewater can be effectively carried out in packed bed reactors (PBRs) employing immobilized microorganisms. A low-cost, reusable immobilization matrix in PBR can provide economic advantages in large scale removal of high concentration phenol. In this study, we evaluated the efficiency and reusability of sugarcane bagasse (SCB) as a low-cost immobilization support for high strength phenol removal in recirculating upflow PBR. An isolated yeast Candida tropicalis PHB5 was immobilized onto the SCB support and packed into the reactor to assess phenol biodegradation at various influent flow rates. Scanning electron microscopy exhibited substantial cell attachment within the pith and onto the fibrous strand surface of the SCB support. The PBR showed 97% removal efficiency at the initial phenol concentration of 2400 mg L-1 and 4 mL min-1 flow rate within 54 h. Biodegradation kinetic studies revealed that the phenol biodegradation rate and biodegradation rate constant were dependent on the influent flow rate. A relatively higher rate of biodegradation (64.20 mg g-1 h-1) was found at a flow rate of 8 mL min-1, indicating rapid phenol removal in the PBR. Up to six successive batches (phenol removal >94%) were successfully applied in the PBR using an initial phenol concentration of 400-2400 mg L-1 at a flow rate of 4 mL min-1 indicating the reusability of the PBR system. The SCB-immobilized C. tropicalis could be employed as a cost-effective packing material for removal of high strength phenolic compounds in real scale PBR.


Assuntos
Reatores Biológicos/microbiologia , Candida tropicalis/metabolismo , Células Imobilizadas/metabolismo , Celulose/química , Fenol/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Cinética , Saccharum/química , Águas Residuárias/química
16.
Environ Sci Pollut Res Int ; 26(20): 21052-21058, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31144183

RESUMO

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.


Assuntos
Bactérias/metabolismo , Benzo(a)pireno/metabolismo , Células Imobilizadas/metabolismo , Poluentes Ambientais/metabolismo , Consórcios Microbianos , Alginatos , Bactérias/classificação , Biodegradação Ambiental , Células Imobilizadas/classificação , Cupriavidus/classificação , Cupriavidus/metabolismo
17.
Artigo em Inglês | MEDLINE | ID: mdl-31003581

RESUMO

In this study, we investigated the effect of different cell-to-matrix ratios (1% and 4%) on the partial nitrification of phosphorylated polyvinyl alcohol-entrapped-cell-based reactors and evaluated the microenvironment, microbial community, and microbial localization within the gel matrices. The results indicated that the reactor with a 1% cell-to-matrix ratio required 184 days of operation to reach partial nitrification that produced anaerobic ammonium oxidation-suitable effluent. In contrast, partial nitrification was achieved from the beginning of the operation of the reactor with the 4% cell-to-matrix ratio. The oxygen-limiting zone (dissolved oxygen = 0.5-1.5 mg L-1), where nitrite-oxidizing activity has been suggested to be suppressed and ammonia-oxidizing activity was reported to be maintained, occurred at 10-230 µm from the gel matrices surface. In addition, the layer of ammonia-oxidizing bacteria observed in this zone is likely to have played a role in obstructing oxygen penetration into the inner region of the gel matrices. The next-generation sequencing results indicated that members of the family Nitrosomonadaceae accounted for 16.4-20.7% of the relative abundance of bacteria at the family level, while members of the family Bradyrhizobiaceae, to which the genus Nitrobacter belongs, accounted for approximately 10% of the relative abundance of bacteria at the genus level in the gel matrices.


Assuntos
Bactérias/metabolismo , Reatores Biológicos/microbiologia , Microbiota , Nitrificação , Amônia/metabolismo , Bactérias/classificação , Bactérias/genética , Células Imobilizadas/metabolismo , Nitritos/metabolismo , Oxirredução , Oxigênio/metabolismo
18.
PLoS One ; 14(4): e0214580, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30990847

RESUMO

A potentiometric whole cell biosensor based on immobilized marine bacterium, Pseudomonas carrageenovora producing κ-carrageenase and glycosulfatase enzymes for specific and direct determination of κ-carrageenan, is described. The bacterial cells were immobilized on the self-plasticized hydrogen ion (H+)-selective acrylic membrane electrode surface to form a catalytic layer. Hydrogen ionophore I was incorporated in the poly(n-butyl acrylate) [poly(nBA)] as a pH ionophore. Catalytic decomposition of κ-carrageenan by the bienzymatic cascade reaction produced neoagarobiose, an inorganic sulfate ion and a proton. The latter was detectable by H+ ion transducer for indirect potentiometric quantification of κ-carrageenan concentration. The use of a disposable screen-printed Ag/AgCl electrode (SPE) provided no cleaning requirement and enabled κ-carrageenan detection to be carried out conveniently without cross contamination in a complex food sample. The SPE-based microbial biosensor response was found to be reproducible with high reproducibility and relative standard deviation (RSD) at 2.6% (n = 3). The whole cell biosensor demonstrated a broad dynamic linear response range to κ-carrageenan from 0.2-100 ppm in 20 mM phosphate buffer saline (PBS) at pH 7.5 with a detection limit at 0.05 ppm and a Nernstian sensitivity of 58.78±0.87 mV/decade (R2 = 0.995). The biosensor showed excellent selectivity towards κ-carrageenan compared to other types of carrageenans tested e.g. ι-carrageenan and λ-carrageenan. No pretreatment to the food sample was necessary when the developed whole cell biosensor was employed for direct assay of κ-carrageenan in dairy product.


Assuntos
Técnicas Biossensoriais , Carragenina/análise , Potenciometria/métodos , Pseudomonas/metabolismo , Algoritmos , Proteínas de Bactérias/metabolismo , Células Imobilizadas/metabolismo , Meios de Cultura , Eletrodos , Hidrogênio , Íons , Cinética , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Fatores de Tempo
19.
ACS Appl Mater Interfaces ; 11(20): 18242-18253, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31021079

RESUMO

Congenital heart disease is the number one cause of birth defect-related death because it often leads to right ventricular heart failure (RVHF). One promising avenue to combat this RVHF is the use of cardiac patches composed of stem cells and scaffolds. Herein, we demonstrate a reparative cardiac patch by combining neonatal or child c-kit+  progenitor cells (CPCs) with a scaffold composed of electrospun polycaprolactone nanofibers. We examined different parameters of the patch, including the alignment, composition, and surface properties of the nanofibers, as well as the age of the CPCs. The patch based on uniaxially aligned nanofibers successfully aligned the CPCs. With the inclusion of gelatin in the nanofiber matrix and/or coating of fibronectin on the surface of the nanofibers, the metabolism of both neonatal and child CPCs was generally enhanced. The conditioned media collected from both patches based on aligned and random nanofibers could reduce the fibrotic gene expression in rat cardiac fibroblasts, following stimulation with transforming growth factor ß. Furthermore, the conditioned media collected from the nanofiber-based patches could lead to the formation of tubes of human umbilical vein endothelial cells, indicating the pro-angiogenic capability of the patch. Taken together, the electrospun nanofiber-based patches are a suitable delivery vehicle for CPCs and can confer reparative benefit through anti-fibrotic and pro-angiogenic paracrine signaling.


Assuntos
Células Imobilizadas/metabolismo , Células Imobilizadas/transplante , Miocárdio/metabolismo , Nanofibras/química , Transplante de Células-Tronco , Células-Tronco/metabolismo , Animais , Células Imobilizadas/patologia , Pré-Escolar , Feminino , Fibroblastos/metabolismo , Fibroblastos/patologia , Cardiopatias Congênitas/metabolismo , Cardiopatias Congênitas/patologia , Cardiopatias Congênitas/terapia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Células Endoteliais da Veia Umbilical Humana/patologia , Humanos , Lactente , Recém-Nascido , Masculino , Miocárdio/patologia , Ratos , Células-Tronco/patologia
20.
Bioprocess Biosyst Eng ; 42(7): 1215-1224, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30953175

RESUMO

In this work, we present a biocompatible one-pot processing route for ceramic/hydrogel nanocomposites in which we embed live bacteria. In our approach, we fabricate a highly stable alginate hydrogel with minimal shrinkage, highly increased structural and mechanical stability, as well as excellent biocompatibility. The hydrogel was produced by ionotropic gelation and reinforced with alumina nanoparticles to form a porous 3D network. In these composite gels, the bacteria Escherichia coli and Bacillus subtilis were embedded. The immobilized bacteria showed high viability and similar metabolic activity as non-embedded cells. Even after repeated glucose consumption cycles, the material maintained high structural stability with stable metabolic activity of the immobilized bacteria. Storing the bionanocomposite for up to 60 days resulted in only minor loss of activity. Accordingly, this approach shows great potential for producing macroscopic bioactive materials for biotechnological processes.


Assuntos
Bacillus subtilis/metabolismo , Células Imobilizadas/metabolismo , Cerâmica/química , Escherichia coli/metabolismo , Hidrogéis/química , Nanocompostos/química , Bacillus subtilis/citologia , Células Imobilizadas/citologia , Escherichia coli/citologia , Viabilidade Microbiana
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