Κυριακή 17 Νοεμβρίου 2019

Monogalactosyldiacylglycerols with High PUFA Content From Microalgae for Value-Added Products

Abstract

Monogalactosyldiacylglycerols (MGDGs) from microalgae containing a high proportion of polyunsaturated fatty acids (PUFAs) have enormous potential applications in various industries. In this study, the productivity and fatty acid composition of MGDGs from three microalgae in commercialized production, Chlorella sorokiniana GT, Nannochloropsis oceanica IMET1, and Arthrospira platensis, were evaluated under nitrogen-sufficient (+N) and nitrogen-deficient (−N) conditions. Under +N conditions, higher productivities of MGDGs from C. sorokiniana GT1, N. oceanica IMET1, and A. platensis were obtained with 16.3, 4.3, and 1.3 mg/L/day, respectively. In agreement with a high ratio of PUFAs in MGDGs, they accounted for 56%, 66%, and 47% of the total fatty acids in MGDG correspondingly. α-linoleic acid (ALA), eicosapentaenoic acid (EPA), and γ-linoleic acid (GLA) were the specific PUFAs of the three microalgae. The proportions of the specific PUFAs in MGDG accounted for 26%, 44%, and 63% of total specific PUFAs, respectively. Considering the production, cost of microalgae biomass and price of MGDG, the commercialized microalgae C. sorokiniana GT1 and A. platensis showed great potential to produce MGDGs with a high content of PUFAs, in contrast to N. oceanica IMET1, with its high biomass cost and low production. This study provides basic data for the extraction and separation of microalgae lipids from commercialized microalgae, which is helpful to promote the commercialization of microalgae.

Efficient biocatalyst of L-DOPA with Escherichia coli expressing a tyrosine phenol-lyase mutant from Kluyvera intermedia

Abstract

L-DOPA (L-dihydroxyphenylalanine) is a promising drug for Parkinson’s disease and thereby has a growing annual demand. Tyrosine phenol-lyase (TPL)–based catalysis is considered to be a low-cost yet efficient route for biosynthesis of L-DOPA. TPL is a tetrameric enzyme that catalyzes the synthesis of L-DOPA from pyrocatechol, sodium pyruvate, and ammonium acetate. The implementation of TPL for L-DOPA production has been hampered and the need for the most efficient TPL source with higher L-DOPA production and substrate conversion rate is prevailing. This study involves identifying a novel TPL from Kluyvera intermedia (Ki-TPL) and displayed a robust expression in Escherichia coli. The recombinant strain YW000 carrying Ki-TPL proved strong catalytic activity with a highest L-DOPA yield compared with 16 other TPLs from different organisms. With a further aim to improve this efficiency, random mutagenesis of Ki-TPL was performed and a mutant namely YW021 was obtained. The whole cells of YW021 as biocatalyst yielded 150.4 g L−1 of L-DOPA with a 99.99 % of pyrocatechol conversion at the optimum condition of pH 8.0 at 25 °C, which is the highest level reported to date. Further, the homology modeling and structural analysis revealed the mutant residues responsible for the extensive L-DOPA biosynthesis.

Loop-Mediated Isothermal Amplification (LAMP) for Detection of Ureaplasma diversum from Cervico-vaginal Swab of Buffaloes

Abstract

The main plan of the current study was to develop a rapid, robust, and field-applicable loop-mediated isothermal amplification (LAMP) assay for the detection of Ureaplasma diversum. A strain-specific 16S rRNA gene of Ureaplasma diversum was used for detection which was cloned, sequenced, and characterized earlier. LAMP results were visualized within 90 min with the naked eye. Cervico-vaginal swabs of 50 buffaloes were randomly collected from Livestock Research Center of NDRI as per the Institute Animal ethics guidelines. Out of 50 cervico-vaginal swab samples collected randomly, 34 were found positive with LAMP while 16 samples were negative. Conventional PCR results showed the same result. Therefore, the accuracy of the developed LAMP was about 100%. The developed LAMP assay can also be used to screen the animals for Ureaplasma diversum infection in cervico-vaginal swab. However, further study is needed to assess sensitivity and accuracy towards their detection and their relationship in disease diagnosis.

Effects of Liquid Hot Water Combined with 1, 4-Butanediol on Chemical Composition and Structure of Moso Bamboo

Abstract

The effects of liquid hot water combined with 1, 4-butanediol (LHW-BDO) on the chemical composition and structure of moso bamboo were investigated. The structure changes of moso bamboo fibers were characterized by infrared spectroscopy, X-ray diffraction, and electronic scanning electron microscopy. The results showed that the delignification rates of 1, 4-butanediol (BDO) and LHW-BDO pretreatment methods were at the same level (91.42–93.08%). However, compared with BDO pretreatment, the cellulose content in solid residue after LHW-BDO pretreatment was increased by 17.06% with a recovery rate of 75.68%, while the hemicellulose removal rate increased by 115.33% and reached 50.34%. After LHW-BDO pretreatment, the intramolecular hydrogen bonds, intermolecular hydrogen bonds, methylene bonds, and aromatic ether bonds of the fibers were broken, which contributed to the depolymerization and separation of cellulose, hemicellulose, and lignin molecules. However, LHW-BDO pretreatment does not destroy the β-glycoside bond which links the glucose molecule inside the fiber molecule, which was also beneficial to the separation of cellulose. In addition, the amorphous zone of bamboo fibers was destroyed by the above treatments, and the fiber structure of bamboo samples mostly exists in crystalline form. The crystallinity of bamboo pretreated with LHW-BDO was increased by 32.15%. It can be found by scanning electron microscopy that the surface of the pretreated bamboo samples showed uniformly distributed bubbly protuberance.

Design of a Real-time Self-adjusting Calibration Algorithm to Improve the Accuracy of Continuous Blood Glucose Monitoring

Abstract

The aim of this study is to establish a real-time self-adjusting calibration algorithm to compensate for signal drift and sensitivity attenuation of subcutaneous implantable glucose sensors. A real-time self-adjusting in vivo calibration method was designed based on the one-point calibration model. The current signal was compensated in real-time and the sensitivity was calibrated regularly. The least squares method was used to fit the initial parameters of the model, and then, the in vivo monitored current data was calibrated. Comparing with the mean absolute relative difference (MARD) of the blood glucose concentration by the traditional one-point calibration model (22.85 ± 5.76%), the MARD of the blood glucose concentration calibrated by the real-time self-adjusting in vivo calibration method was 6.28 ± 2.31%. The accuracy of the dynamic blood glucose monitoring was effectively improved. This calibration algorithm could compensate the signal drift in real time and correct sensitivity regularly to improve the accuracy of dynamic glucose monitoring, thus significantly enhancing diabetic self-management.

Microwave-Assisted Biodiesel Production from Microalgae, Scenedesmus Species , Using Goat Bone–Made Nano-catalyst

Abstract

The production of biodiesel from Scenedesmus algal oil is one of the best alternative forms of liquid fuel production from biomass to petrol diesel. Biodiesel plays a significant role in the carbon sequestration process during cultivation. Scenedesmus algal species was isolated and cultured in a bold basal medium by using nonheat releasing white florescence (2500 lx) for a 12:12-h dark and light cycle. Algae oil was extracted from dried microalgae biomass through a microwave digester–assisted solvent extraction method. Consequently, about 20.8% algal oil per gram was obtained. A waste-based calcium oxide (CaO) nano-catalyst prepared from goat bone was used in the transesterification process. The catalyst was calcinated at 900 °C and characterized using FTIR, SEM, EDX, and XRD techniques. The results revealed a mean particle size of 43.96 nm with an irregular shape, porous structure, and possession of many active sites. The optimized transesterification process offers an optimum biodiesel yield of 92% at the experimental conditions, i.e., at a reaction temperature of 60 °C, 2% (Wt.) catalyst loading and 11:1 methanol to algal oil molar ratio, 1500 rpm stirring speed, and 3 h reaction duration. The physicochemical properties of the produced biodiesel were tested according to ASTM D6751 standards and are in good agreement.

Density Functional Theory and Molecular Simulation Studies for Prioritizing Anaplastic Lymphoma Kinase Inhibitors

Abstract

Targeting anaplastic lymphoma kinase (ALK) is one of the important treatment strategies for the treatment of non-small cell lung cancer (NSCLC). In the present perspective, multidimensional approaches were used for the identification of ALK inhibitors. Initially, an e-pharmacophore model was generated using the PHASE algorithm and was used as a 3D query to screen 468,200 molecules of ASINEX database. Prior to the screening process, the model was evaluated for its significance and the ability to differentiate actives from inactives, using enrichment analysis. Subsequently, the hierarchical docking protocol and binding free energy calculations were instigated using GLIDE algorithm and Prime module, respectively. Further, the pharmacokinetic/pharmacodynamics (PK/PD) properties and toxicities of the hit compounds were envisaged respectively using QikProp program, Osiris explorer, and Protox-II algorithm. These approaches retrieved two hits namely BAS 00137817 and BAS 00680055 with acceptable absorption, distribution, metabolism, excretion and toxicity (ADMET) properties and higher affinity towards ALK protein. Additionally, density functional theory calculations and molecular dynamics simulations were performed to validate the inhibitory activity of the lead compounds. It is noteworthy to mention that all the hits constitute of particular scaffolds which play a major role in the downregulation of some ALK-positive lung cancer pathways. We speculate that the outcomes of this research are of substantial prominence in the rational designing of novel and efficacious ALK inhibitors.

Preparation and Optimization of a Biomimetic Triple-Layered Vascular Scaffold Based on Coaxial Electrospinning

Abstract

Electrospinning is a promising method for preparing bionic vascular scaffolds. In particular, coaxial electrospinning can encapsulate polymer materials in biological materials and provide vascular scaffolds with good biomechanical properties. However, it is difficult to produce a stable Taylor cone during the coaxial electrospinning process. Moreover, glutaraldehyde cross-linked natural biomaterials are cytotoxic. To address these issues, a novel electrospinning process is proposed in this report. A non-ionic surfactant (Tween 80) was added to poly(lactic-co-glycolic acid) electrospinning solution and gelatin-collagen electrospinning solution, which prevented the interfacial effect of coaxial electrospinning due to different core/shell solutions. The as-prepared materials were then cross-linked with the non-toxic coupling agents N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide/N-hydroxysuccinimide (EDC/NHS). By comparing the biomechanical properties of EDC/NHS cross-linked vascular scaffold with glutaraldehyde vapor–cross-linked vascular scaffold, it was found that the fracture strain and biological performance of EDC/NHS cross-linked vascular scaffold were better than those of the glutaraldehyde cross-linked scaffold. Finally, a three-layer bionic vascular scaffold was prepared by the proposed electrospinning process. Biomechanical performance tests were carried out and the prepared scaffold was found to meet the requirements of tissue-engineered blood vessels. The research in this paper provides a useful reference for the preparation and optimization of vascular scaffolds.

Solid-state Co-cultivation of Bacillus subtilis , Bacillus mucilaginosus , and Paecilomyces lilacinus Using Tobacco Waste Residue

Abstract

Agro-industrial wastes are excellent sources for solid-state culture to produce spores of microorganisms, whereas microbial co-cultivation is not fully exploited in solid-state culture. In this work, the co-cultivation of different strains of Bacillus subtilis, and three microbes of B. subtilisBacillus mucilaginosus, and Paecilomyces lilacinus was studied using a solid medium only composed of water and tobacco waste residue after extraction of nicotine and solanesol. The influences of matrix thickness, moister, temperature, and ratio of three microbes in seed on the cell growth and spore formation were studied. The maximum viable cells and spores of each microbe reached 1013 cfu/g when cultured alone at 30 °C in a medium containing 58.3% moisture. Co-cultivation of microbes stimulated cell growth and maximum viable cells of each microbe reached 1014 cfu/g, while spore production was inhibited and decreased to 1011 cfu/g. With decreasing amount of P. lilacinus in seed, total amount of spores was increased. When the seed with a ratio of 6:3:1 for B. mucilaginosusB. subtilis, and P. lilacinus was inoculated, the total amount of spores reached 4.14 × 1012 cfu/g and the ratio was 1.7:0.7:1. These results indicate the potential of solid-state cultivation in the high production of spores from tobacco waste residue at low cost.

Enzymatic Synthesis of a Diene Ester Monomer Derived from Renewable Resource

Abstract

The total or partial substitution of fossil raw materials by biobased materials from renewable resources is one of the great challenges of our society. In this context, the reaction under mild condition as enzyme-catalyzed esterification was applied to investigate the esterification of the biobased 10-undecenoic acid with 2-hydroxyethyl methacrylate (HEMA) to obtain a new diene ester monomer. The environmentally friendly enzymatic reaction presented up to 100% of conversion; moreover, the production of possible by-products was minimized controlling reaction time and amount of enzyme. Furthermore, the presence of chloroform was evaluated during the enzymatic reactions and despite high conversions with higher enzyme concentration, the solvent-free system showed fast kinetics even with 1.13 U/g substrates. In addition, the commercial immobilized lipases Novozym 435 and NS 88011 could be applied for up to 10 cycles keeping conversions about 90%. The scale-up of the reaction was possible and a purification procedure was applied in order to isolate the diene ester monomer 2-(10-undecenoyloxy)ethyl methacrylate, preserving its double bonds, which could allow a potential use of this product in the synthesis of new renewable polymers through techniques as metathesis, thiol-ene, or free-radical polymerization.

Δεν υπάρχουν σχόλια:

Δημοσίευση σχολίου