In the present work, we demonstrate the transmittance properties of one dimensional (1D) quasi-periodic photonic crystals that contain a superconductor material and a hyperbolic metamaterial (HMM). A HMM layer is engineered by the subwavelength undoped and doped Indium Arsenide (InAs) multilayers. Many resonance peaks with angle stability are obtained from the proposed Fibonacci sequence structure using the transfer matrix method (TMM).
View Article and Find Full Text PDFIn the present research work we have theoretically examined the biosensing capabilities of proposed one dimensional defective photonic crystal for swift detection of malignant brain tissues. The transfer matrix formulation and MATLAB computational tool have been used to examine the transmission properties of proposed structure. The identical buffer layers of nanocomposite superconducting material have been used either side of cavity region to enhance the interaction between incident light and different brain tissue samples poured into the cavity region.
View Article and Find Full Text PDFIn this research, we have a theoretical simple and highly sensitive sodium chloride (NaCl) sensor based on the excitation of Tamm plasmon resonance through a one-dimensional photonic crystal structure. The configuration of the proposed design was, [prism/gold (Au)/water cavity/silicon (Si)/calcium fluoride (CaF)/glass substrate]. The estimations are mainly investigated based on both the optical properties of the constituent materials and the transfer matrix method as well.
View Article and Find Full Text PDFThe light-slowing effect near band endpoints is frequently exploited in photonic crystals to enhance the optical transmittance. In a one-dimensional binary photonic crystal (1DPC) made of hyperbolic metamaterials (HMMs), we theoretically examined the angle-dependent omnidirectional photonic bandgap (PBG) for TM polarization. Using the transfer matrix approach, the optical characteristics of the 1DPC structure having dielectric and HMM layers were examined at the infrared range (IR).
View Article and Find Full Text PDFWe have theoretically demonstrated and explored the transmittance characteristics of a one-dimensional binary photonic crystal composed of metamaterial (MM) and nanocomposite (NC) layers. The NC layer was designed from silver nanoparticles (Ag-NPs) in a host material as Yttrium oxide (YO). Using the transfer matrix approach (TMM), the optical properties of a one-dimensional binary periodic structure having MM and NC layers in the Giga Hertz (GHz) range were examined.
View Article and Find Full Text PDFBacteria that successfully adapt to different substrates and environmental niches within the lung and overcome the immune defence can cause serious lung infections. Such infections are generally complex, and recognized as polymicrobial in nature. Both Pseudomonas aeruginosa and Streptococcus pneumoniae can cause chronic lung infections and were both detected in cystic fibrosis (CF) lung at different stages.
View Article and Find Full Text PDFIn this work, we have explored a novel application of one-dimensional (1D) photonic crystals (PCs) as a biomarker for the detection of organic materials in wastewater. The high concentration of organic materials may lead to adverse impact on human life. In order to save human life from these adverse effects, we have investigated the bio-alcohol sensing properties of a 1D multilayer periodic structure capable of detecting organic materials in wastewater.
View Article and Find Full Text PDFIn this contribution, we studied the effect of electro-fermentation on the butanol production of strains by a targeted metabolomics approach. Two strains were examined: an electrocompetent wild type strain (R525) and a mutant strain (dhaB mutant) lacking formation of 1,3-propanediol (PDO). The dhaB-negative strain was able to grow on glycerol without formation of PDO, but displayed a high initial intracellular NADH/NAD ratio which was lowered subsequently by upregulation of the butanol production pathway.
View Article and Find Full Text PDFPropionic acid (PA) is a valuable organic acid for the food and feed industry, but no bioproduction at industrial scale exists so far. As product inhibition is a major burden for bioprocesses producing organic acids, in situ product removal (ISPR) is desirable. Here, we demonstrate a new strategy to produce PA with a co-culture coupled with ISPR using electrodialysis.
View Article and Find Full Text PDFPseudomonas aeruginosa is characterized by its capability to produce extracellular virulence proteins and to establish biofilm-based infections that do not respond easily to conventional treatments. However, the physiological conditions that decrease the fitness of such a persistent pathogen would assist the host to defend itself and reduce the infection prevalence. Therefore, developing treatments against P.
View Article and Find Full Text PDFMicrobial electrosynthesis or electro-fermentation in bioelectrochemical systems (BES) have recently received much attention. Here, we demonstrate with the glycerol metabolism by Clostridium pasteurianum that H from in situ water electrolysis, especially in combination with a redox mediator, provides a simple and flexible way for shifting product selectivity and enhancing product yield in the fermentation process. In particular, we report and quantify for the first time strictly different effects of Neutral Red (NR) and the barely studied redox mediator Brilliant Blue (BB) on the growth and product formation of C.
View Article and Find Full Text PDFThe opportunistic pathogen Pseudomonas aeruginosa causes chronic respiratory infections in patients with cystic fibrosis (CF). Persistence of this bacterium is attributed to its ability to form biofilms which rely on an extracellular polymeric substance matrix. Extracellular polysaccharides (EPS) and secreted proteins are key matrix components of P.
View Article and Find Full Text PDFproduces industrially valuable chemicals such as -butanol and 1,3-propanediol from fermentations of glycerol and glucose. Metabolic engineering for increased yields of selective compounds is not well established in this microorganism. In order to study carbon fluxes and to selectively increase butanol yields, we integrated the latest advances in genome editing to obtain an electrocompetent strain for further engineering.
View Article and Find Full Text PDFWe develop and explore a nonlinear regression modeling approach to designing subtractive color filters (SCFs) based on plasmonic metasurfaces. The approach opens up the possibility of rapidly choosing a desired optimized SCF design with high color saturation and brightness using an analytical expression. In this Letter, colors are produced by absorbing the light of specific wavelengths and reflecting the remaining spectrum with silver gap-plasmon nanoantennas deposited on a silver film.
View Article and Find Full Text PDFBackground: Unlike the well-studied backer yeast where catabolite repression represents a burden for mixed substrate fermentation, Yarrowia lipolytica, an oleaginous yeast, is recognized for its potential to produce single cell oils and citric acid from different feedstocks. These versatilities of Y. lipolytica with regards to substrate utilization make it an attractive host for biorefinery application.
View Article and Find Full Text PDFBackground: Clostridium pasteurianum as an emerging new microbial cell factory can produce both n-butanol (BuOH) and 1,3-propanediol (1,3-PDO), and the pattern of product formation changes significantly with the composition of the culture medium. Among others iron content in the medium was shown to strongly affect the products selectivity. However, the mechanism behind this metabolic regulation is still unclear.
View Article and Find Full Text PDFBackground: Clostridium pasteurianum is becoming increasingly attractive for the production of chemicals and fuels such as n-butanol and 1,3-propanediol. Previously we have shown that dual substrate fermentation using glucose and glycerol enhanced the cell growth and butanol production significantly. Although C.
View Article and Find Full Text PDFis a robust oleaginous yeast that can accumulate lipids to more than 70% of its dry cell mass. Even though it is extensively studied for its fermentation of substrates like glucose and glycerol, limited information is available about its metabolism of mixture of glucose and glycerol. During growth on mixture of glucose and glycerol a typical diauxic growth and higher lipid yields were observed.
View Article and Find Full Text PDFDiols are compounds with two hydroxyl groups and have a wide range of appealing applications as chemicals and fuels. In particular, five low molecular diol compounds, namely 1,3-propanediol (1,3-PDO), 1,2-propanediol (1,2-PDO), 2,3-butanediol (2,3-BDO), 1,3-butanediol (1,3-BDO), and 1,4-butanediol (1,4-BDO), can be biotechnologically produced by direct microbial bioconversion of renewable materials. In this review, we summarize recent developments in the microbial production of diols, especially regarding the engineering of typical microbial strains as cell factory and the development of corresponding bioconversion processes.
View Article and Find Full Text PDFBackground: Microbial lipids (triacylglycerols, TAG) have received large attention for a sustainable production of oleochemicals and biofuels. Rhodosporidium toruloides can accumulate lipids up to 70% of its cell mass under certain conditions. However, our understanding of lipid production in this yeast is still much limited, especially for growth with mixed substrates at the level of metabolic network.
View Article and Find Full Text PDFStillage, which is generated during bioethanol production, constitutes a promising substrate for biogas production within the scope of an integrated biorefinery concept. In this study, a microbial community was grown on thin stillage as mono-substrate in a continuous stirred tank reactor (CSTR) at a constant temperature of 55 °C, at an organic loading rate of 1.5 goTS/L*d and a retention time of 25 days.
View Article and Find Full Text PDFThe kinetics of growth, acid and solvent production in batch culture of Clostridium pasteurianum DSMZ 525 were examined in mixed or mono-substrate fermentations. In pH-uncontrolled batch cultures, the addition of butyric acid or glucose significantly enhanced n-butanol production and the ratio of butanol/1,3-propanediol. In pH-controlled batch culture at pH = 6, butyric acid addition had a negative effect on growth and did not lead to a higher n-butanol productivity.
View Article and Find Full Text PDFSmall-colony variants (SCVs) of Pseudomonas aeruginosa are often found in chronically infected airways of patients suffering from cystic fibrosis. These slow-growing morphological variants have been associated with persistent and antibiotic-resistant infections. Nevertheless, the behavior of SCVs under varied availability of O₂ and iron, two key variables relevant to the lung environment of CF patients and pathogenicity of P.
View Article and Find Full Text PDF: In this work a defined co-culture of the lactic acid bacterium Lactobacillus zeae and the propionate producer Veillonella criceti has been studied in continuous stirred tank reactor (CSTR) and in a dialysis membrane reactor. It is the first time that this reactor type is used for a defined co-culture fermentation. This reactor allows high mixing rates and working with high cell densities, making it ideal for co-culture investigations.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
July 2013
Propionic acid is presently mainly produced by chemical synthesis. For many applications, especially in feed and food industries, a fermentative production of propionic acid from cheap and renewable resources is of large interest. In this work, we investigated the use of a co-culture to convert household flour to propionic acid.
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