Fourier Transform Nuclear Magnetic Resonance Research Articles

Phase-Incremented Steady-State Free Precession as an Alternate Route to High-Resolution NMR.

Pulsed Fourier transform nuclear magnetic resonance (FT-NMR) has reigned supreme in high-resolution, high-field spectroscopy─particularly when targeting complex liquid-state samples involving multiple sharp peaks spread over large spectral bandwidths. It is known, however, that if spectral resolution is not a must, the FT-based approach is not necessarily the optimal route for maximizing NMR sensitivity: if T2 ≈ T1, as often found in solutions, Carr's steady-state free-precession (SSFP) approach can in principle provide a superior signal-to-noise ratio per √(acquisition_time) (SNRt). A rapid train of pulses will then lead to a transverse component that reaches up to 50% of the thermal equilibrium magnetization, provided that pulses are applied at repetition times TR ≪ T2, T1, and that a single suitable offset is involved. It is generally assumed that having to deal with multiple chemical shifts deprives SSFP from its advantages. The present study revisits this assumption by introducing an approach whereby arbitrarily short SSFP-derived free induction decays (FIDs) can deliver high-resolution spectra, without suffering from peak broadenings or phase distortions. To achieve discrimination among nearby frequencies, signals arising from a series of regularly phase-increased excitation pulses are collected. Given SSFP's amplitude and phase sensitivity to the spins' offset, this enables the resolution of sites according to their chemical shift position. In addition, the extreme fold-over associated with SSFP acquisitions is dealt with by a customized discrete FT of the interpulse time-domain signal. Solution-state 13C NMR spectra which compare well with FT-NMR data in terms of sensitivity, bandwidth, and resolution can then be obtained.

Growth and Characterization of Organic 2-Chloro 5-Nitroaniline Crystal Using the Vertical Bridgman Technique

In this article, we discuss the preparation of organic 2-chloro-5 nitroaniline (2C5NA) crystals and their different kinds of physical, chemical, and mechanical properties. The vertical Bridgman approach was used to effectively produce the bulk organic 2C5NA crystal. To produce a good-quality bulk crystal, the shape, dimensions, and cone angle of the ampoule were optimized. Also, the temperature profile was set for the 2C5NA crystal. The growth atmosphere and the lowering rate were identified to obtain a homogeneous mixture of the compounds and initiate the nucleation process. Single-crystal X-ray diffraction (XRD), powder XRD, proton Fourier transform nuclear magnetic resonance (FT-NMR), and Fourier transform infrared investigations were used to confirm the crystal structure, molecular structure, and presence of functional groups in the formed crystal. The formed crystal has a monoclinic crystal structure with the space group P21/c, according to single-crystal XRD analysis. The thermal stability and kinetic parameters were examined using thermogravimetric analysis and differential thermal curves. From dielectric analysis, the electrical conductivity and dielectric behavior of 2C5NA were investigated with variations in frequency and temperature. The organic 2-chloro-5-nitroaniline crystal demonstrates that the indentation size effect is observed in the Vickers micro-hardness test, which was also carried out.

Cocrystal Construction Between Rosuvastatin Calcium and L-asparagine with Enhanced Solubility and Dissolution Rate.

Rosuvastatin calcium (RSC) is a synthetic biopharmaceutical classification system class-II drug with a low solubility but high permeability. The drug is used in hyperlipidemia management. In this study, the physicochemical properties of RSC were modified via crystal engineering to produce a cocrystal form. The solvent evaporation method was used to fabricate RSC cocrystals with the generally recognized as safe status coformer, L-asparagine. The obtained cocrystals were evaluated using powder X-ray diffraction (PXRD), scanning electron microscopy, fourier-transform infrared spectroscopy, differential scanning calorimetry (DSC), and fourier-transform nuclear magnetic resonance (FT-NMR). The PXRD analysis revealed the presence of unique crystalline peaks, which provide details of interactions between the active pharmaceutical ingredient and coformer. The changes in the thermal behavior of the cocrystals were confirmed by DSC studies. The formation of a hydrogen bond between the drug and conformer was confirmed by a change in the chemical shift values of the FT-NMR spectra at the O-H group. Comparative studies of the solubility and dissolution rate revealed that the solubility and dissolution rate of the obtained cocrystals were almost two times higher than those of the parent drug. A new cocrystal form of RSC was obtained with a higher solubility and dissolution rate than those of the parent drug, implying new applications for these cocrystals.

Development of active barrier effect of hybrid chitosan/silica composite epoxy-based coating on mild steel surface

In this study, a co-action behavior of a hybrid composed of chitosan and silica was investigated by incorporating it into an epoxy resin to induce an active barrier effect on the metal surface. The chemical structure and porosity of the hybrid chitosan and silica were determined using Fourier-Transform Nuclear Magnetic Resonance (FT-NMR) and Brunauer–Emmett–Teller (BET), respectively. The dispersion of the hybrid chitosan/silica incorporated within the epoxy matrix was observed via Environmental Scanning Electron Microscopy (ESEM) and Fourier Transform Infrared Spectroscopy (FTIR). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were exploited to examine the thermal stability. The wettability and degree of transparency of the hybrid composite coatings were found to be increased after being exposed to the corrosive medium and also were investigated using the contact angle (CA) measurement and ultraviolet-visible (UV–Vis) spectroscopy, respectively. CS0.8 coating has shown an increase in contact angle from 82.4 at normal condition and 89.4 and 83.6 to the exposure to NaCl solution and UV exposure respectively. The active barrier effect of the developed hybrid composite coating on mild steel surface was evaluated by the electrochemical impedance spectroscopy (EIS) in 3.5 wt.% NaCl solution to which 0.8 wt.% of hybrid chitosan/silica mass fraction exhibited pronounced impedance value up to 1010 Ω cm2 and the breakpoint frequency performed a full capacitive region even after the 60th day of exposure to the accelerated corrosive ions penetration test.

Novel pH-tunable nontoxic hydrogels of pyrrole-2-carboxylic acid and ethylenediamine derivatives: synthesis and characterization

ABSTRACT In this study, attention has been paid to synthesize and investigate pH-sensitive biopolymeric hydrogel from renewable resource-based monomers such as citric acid, pyrrole-2-carboxylic acid, and ethylenediamine through two-step condensation polymerization. The formation of hydrogel and structure of hydrogel were confirmed by Fourier-transform spectroscopy and nuclear magnetic resonance spectroscopy (1H-NMR and 13C-NMR) analyses. Thermal stability and glass transition temperature of hydrogel were analyzed by thermogravimetric analysis and differential scanning calorimetry analysis. Swelling studies of the hydrogel at various pH media ranging from 3.0 to 10.0 have also investigated. The swelling behavior of hydrogel increased in acidic media than in basic media. Scanning electron microscopic analysis revealed the spherical shape and porous nature of the hydrogel. The antibacterial activity of hydrogel was investigated against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacterial species at different concentrations. The cytotoxicity study of the hydrogel has been carried out using MTT assay method. Hence, the biopolymeric hydrogel with smart pH sensitivity may be considered an excellent candidate for industrial, environmental, and biological applications.

A PRELIMINARY STUDY ON DETECTION OF CADMIUM (II) ION USING BENZOYL PHENYLTHIOUREA

Two benzoyl phenylthiourea derivatives namely: 1-benzoyl-3-(4-bromophenyl)-2- thiourea (M) and 1-(4-chlorobenzoyl)-3-(4-methylphenyl)-2-thiourea (MI) were successfully synthesized and characterized by using Carbon, Hydrogen and Nitrogen (CHN) micro elemental analysis, Fourier Transform Infra-Red (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopy methods. Elemental analysis for M (C14H11N2SOBr) and MI (C15H13N2SOCl) were compatible with the expected theoretical calculation. The FTIR spectrum obtained for M and MI compounds show the presence of four important functional groups; ʋ(N-H), ʋ(C=O), ʋ(C-N) and ʋ(C=S) that appeared at 3380-3367 cm-1, 1666-1681 cm-1, 1342-1268 cm-1 and 1146-1152 cm-1, respectively. The NMR spectrum data for MI shows the chemical shift at 6.63-7.85 ppm for Ar-H group, 2.26-2.40 ppm for methyl group, 7.44 ppm for N1H and 3.09 ppm for N2H. For the application, M and MI were used as probes in detecting Cd2+ in methanol solution. UV-Visible spectrophotometer was used to analyze the absorbance values of the compound before and after Cd2+ was added. It is found that compound M displayed the behavior of ‘turn off’ sensors while compound MI possessed the behavior of ‘turn on’ when detecting 0.5×10-5 M and 1×10- 5 M of Cd2+ ion. The behavior of ‘turn on’ and ‘turn off’ is due to the increasing or decreasing of absorbance when Cd2+ was added to the compounds.

Antimicrobial and Phytochemical Screening of the Methanolic Stem Bark Extract of Ficus abutilifolia (Miq.) and Some Spectral Studies on One Isolated Component

The stem bark extract of Ficus abutilifolia (Miq.) , an ethnomedicinally important member of the Moraceae family, was analysed with the three-fold aim of identifying its phytochemical components, determining its antimicrobial effects and efficacy, and isolating a component to be structurally elucidated by Fourier-Transform Infrared (FTIR) and Proton Nuclear Magnetic Resonance ( 1 HNMR) studies. Extraction was carried out by maceration method with methanol as the extraction solvent. Qualitative phytochemical analysis of the resulting methanolic extract gave positive results for carbohydrates, cardiac glycosides, saponins, steroid, triterpenes and alkaloids, while the antimicrobial screening revealed bioactivity against Staphylococcus aureus , Escherichia coli , and Pseudomonas aeruginosa . The extract was found to be bacteriostatic (growth-inhibitory) to S. aureus , E. coli and P. aeruginosa with respective Minimum Inhibitory Concentration (MIC) values of 25-, 50- and 25 mg/ml, but was bactericidal (lethal) only to S. aureus and P. aeruginosa with a common Minimum Bactericidal Concentration (MBC) value of 50 mg/ml. Column separation led to the successful isolation of a white crystalline substance with R f value of 0.25 using solvent ratio 1:4 of EtOAc:n-hexane solvent system. Studies on the FTIR and 1 HNMR spectra of the isolated compound revealed that it is a non-aromatic, non-conjugated six-membered lactone. Keywords: Ficus abutilifolia , antimicrobial screening, phytochemical, structural elucidation, isolation, stem bark, chromatography DOI: 10.7176/JNSR/10-6-05 Publication date: March 31 st 2020

Synthesis of polymer-supported Brønsted acid-functionalized Zn–porphyrin complex, knotted with benzimidazolium moiety for photodegradation of azo dyes under visible-light irradiation

A polymer-supported Bronsted acid-functionalized Zn–porphyrin complex, knotted with benzimidazolium moiety (PSBAZnPP), has been synthesized and characterized by Fourier transform nuclear magnetic resonance (FT-NMR) and Fourier transform infrared spectroscopy (FTIR). The thermal stability was determined by thermogravimetric analysis (TGA), and surface morphology and elemental composition were investigated by scanning electron microscopy and energy-dispersive spectroscopy (SEM/EDAX). The heterogeneous PSBAZnPP showed high efficacy as a photocatalyst for degradation of azo dyes, such as methyl red (MR), methyl orange (MO) and Congo red (CR), in the presence of visible-light irradiation at ambient condition using atmospheric air/H2O2. The concentration of the dyes was measured by UV–visible spectroscopy, and the degradation of the dyes was confirmed by GC–MS analysis. Further decolorization and degradation of MO were confirmed by using ultra-high-pressure liquid chromatography (UPLC). The optimum degradation was achieved by adding 10 mg catalyst for all azo dyes for 60 min in the presence of air. The effect of scavengers was studied to indicate the most active species generated during photocatalysis. PSBAZnPP furnished a good response toward the photodegradation of MR, MO and CR under optimized conditions. Finally, the mechanism of photocatalytic degradation process was suggested. Relevant active species produced in the PSBAZnPP/H2O2 or PSBAZnPP/air system under visible light were recognized by using different types of scavengers, viz. EDTA, p-benzoquinone (PBQ), terephthalic acid (TPA), sodium azide and sodium nitrate, for determination of formation of holes, $${\text{O}}_{2}^{ \cdot }$$, $${\text{OH}}^{ \cdot }$$, $${}^{1}{\text{O}}_{2}$$ and an aqueous electron (e−), respectively. The comparative acidity of the synthesized PSBAZnPP catalyst was measured using UV–Vis and then equated to relations of the Hammett value (H0). The efficiency of catalyst correlates with a considerable proton level required for degradation of organic dyes.

Designing and building a low-cost portable FT-NMR spectrometer in 2019: A modern challenge

Abstract High-field Fourier-Transform Nuclear Magnetic Resonance (FT-NMR) spectroscopy is a high performance spectroscopic technique that is essential in many analytical fields. The non-destructive nature of NMR makes it a preferred means of analyzing chemical and biological environments. Compact benchtop NMR spectrometers are low-cost alternatives to conventional high-field and high-resolution spectrometers. A research laboratory may want to develop its own compact FT-NMR spectrometer (home-built benchtop NMR) with a very low financial cost (∼10 k€). But why? First of all, to use it punctually as an additional channel (nucleus X) to a high-resolution spectrometer, and also to be able to couple it with complementary physics instruments such as an optical microscope to study spin diffusion in semiconductors, for instance. In addition, a home-built NMR spectrometer can be used with a low-field permanent magnet for the quantification of species that does not necessarily require high-resolution, avoiding the need for weekly and expensive cryogenic services. Outside the research laboratory, this portable NMR can be used for the in situ analysis of outdoor natural environments. Finally, this compact spectrometer is naturally dedicated to the teaching of NMR technique and is open to the study of the basic electronic functions that constitute an NMR spectrometer. The main question then arises: how to build a robust Home-Built” NMR? In this article, we describe the realization of an NMR instrument based on electronic components and boards (LNA, ADC, FPGA, ARM, DDS…) easily commercially available, allowing one to obtain a benchtop NMR instrument presenting both a high acquisition dynamics and a good signal-to-noise ratio.

Synthesis and characterization of polymer supported Fe-phthalocyanine entangled with carboxyl functionalized benzimidazolium moiety: A heterogeneous catalyst for efficient visible-light-driven degradation of organic dyes from aqueous solutions

Phthalocyanines (Pc) are good photosensitizers due to the intensive colour that makes them suitable in oxidation and reduction besides their applications in pigments. In this study, a polymer supported Fe-Phthalocyanine entangled with carboxyl functionalized benzimidazolium moiety (PSFePcCFBM) was synthesized and characterized by analytical techniques such as Fourier-Transform Infrared Spectroscopy (FT-IR), Fourier-Transform Nuclear Magnetic Resonance (FT-NMR) and Thermo Gravimetric Analysis (TGA). The photocatalytic activity of the heterogeneous PSFePcCFBM catalyst was assessed for the degradation of the Methylene Blue (MB), Methyl Violet (MV) and Congo Red (CR). The change in concentration of the dyes was studied by UV–Visible spectroscopy and the degradation dye was confirmed by GC–MS. The complete photocatalytic degradation of the MB, MV and CR was achieved in 60 min with 10 mg, 15 mg and 12.5 mg catalyst respectively with atmospheric air. The catalyst showed admirable activity towards the degradation, devoid of any additives such as ZnO/TiO2 in the presence of 5 W LED lamp as a source of light, and was highly recyclable. Therefore, it was inferred that this protocol is suitable for the degradation of organic pollutants effectively in the absence of any additives.

Preparation and characterization of Aloe vera acetate and electrospinning fibers as promising antibacterial properties materials

In this work, the anti-bacterial effect of Aloe vera derivate fibers produced by the electrospinning method was reported. Aloe vera Polyvinylpyrrolidone (Av/PVP) and Aloe vera acetate-Polyvinylpyrrolidone (AvAc/PVP) electrospun fibers were prepared with different concentrations and their microstructure and mechanical properties were studied. Various methods such as differential scanning calorimetry (DSC), thermogravimetry analysis (TGA), water contact angle (CA) tests, Fourier-Transform Nuclear Magnetic Resonance (FT-NMR), scanning electron microscope (SEM), X-ray diffraction (XRD), CHNSO and Fourier-Transform Infrared Spectroscopy (FT-IR) were used to characterize prepared samples. (Av/PVP) electrospun fibers were prepared with different concentrations (6–10 wt%) of PVP and 0.2 wt% Av blended and tested in medicinal herb for wound healing, antibacterial and anti-inflammatory properties. For further study, the effect of AvAc film on the properties of composite film was studied. AvAc increased the thermal stability and crystallite size percentage of samples. Antibacterial and antiviral test studies on the scaffold displayed no bacterial and viral growth. These results suggest that AvAc/PVP scaffolds could be promising candidates for wound healing applications.

Ruthenocene Precursors for Ruthenium-Containing Thin-Film Deposition: An Example of Solvent Nucleophilic Attack on Fulvene

A new series of ruthenocene complexes were prepared from RuCl3·xH2O and 6,6-dimethylfulvene as potential precursors for thin-film deposition. The formation of these complexes was the result of an unforeseen nucleophilic attack of the solvent molecules (alcohols/amines) on the 6,6-dimethylfulvene ligand during the reaction. Complexes [RuII(C5H4C(CH3)2OCH3)2] (1), [RuII(C5H4C(CH3)2OC2H5)2] (2), [RuII(C5H4C(CH3)2N(CH3)2)2] (3), and [RuII(C5H4C(CH3)2N(CH2CH3)2)2] (4) were isolated in pure form and characterized by Fourier transform (FT) infrared and FT nuclear magnetic resonance spectroscopy as well as elemental and thermogravimetric (TG) analyses. Crystallographic studies of complexes 1–3 revealed a monomeric ruthenocene structure for all complexes and showed that the deprotonated alkylalkoxide or dialkylamide of the solvent molecule was attached to the exocyclic carbon of the fulvene ligand. Although the complexes were formed as ruthenocenes instead of the expected ruthenium fulvene complexes, they all disp...

Phase-transition-like phenomenon of NH4H2PO4 observed using MAS NMR and static NMR near characteristic temperature

We used Fourier-transform nuclear magnetic resonance (NMR) spectroscopy to investigate the temperature dependences of the chemical shift and resonance frequency observed with magic-angle spinning NMR and static NMR, respectively, to confirm a high-temperature behavior of NH4H2PO4. The hydrogen bonds in both O–H–O between two PO4 groups and N–H–O between NH4 and PO4 were distinguished, and the changes occurring in the chemical shift and resonance frequency near the characteristic temperature TP are related to changes in the atomic positions. The experimental results of thermogravimetric analysis conducted to interpret the high-temperature phenomena without the critical change around TP are consistent with a phase-transition-like phenomenon at TP.

Indium complexes bearing donor-functionalized alkoxide ligands as precursors for indium oxide thin films

Novel indium complexes [(CH3)2In(OR)]2 (1–7) were synthesized using a series of donor-functionalized alkoxide ligands as potential precursors for thin-film applications. These complexes showed dimeric configurations with two μ2-O bridging between the metal centers. Moreover, the indium metal centers in these complexes exhibited pentacoordinated states with distorted trigonal-bipyramidal geometry. The complexes were characterized by Fourier transform (FT)-infrared, and FT-nuclear magnetic resonance spectroscopies, elemental analyses, and thermogravimetric analyses (TGA). The TGA curves of complexes 4 and 7 exhibited a single-step mass loss at 100–275 °C, indicating good volatility and thermal stability.

Production of biofuels from fish wastes: an overview

ABSTRACTEvery year billions of tons of fish waste are produced by fish processing units. These wastes when dumped into the environment cause emissions which in turn degrade the land. An alternative solution for the problem involves their processing into biofuel, pharmacological components, fertilizer and fodder. Biofuel is a trending concept and an alternative for present day fuels. Biofuels are pollution free and thus are advantageous over current fuels. Biofuels are produced from organic waste, seaweed, and micro-algae. The current research on fish wastes for the production of biodiesel is mainly because of their nontoxic and biodegradable nature. Biodiesel produces less air toxins, CO2, hydrocarbons and other particulates when compared to the standard fuel or diesel. The conversion process involves extraction of fish oil from the waste of the fishing industry. The oil is cleaned and purified. With the addition of a catalyst, biodiesel and bio-gas are produced by transesterification and anaerobic digestion respectively. Various results such as Fourier transform nuclear magnetic resonance (FT-NMR), gas chromatography mass spectrometry (GCMS) and proton nuclear magnetic resonance (H-NMR) analysis, and best management practices (BMP) assay show the efficient conversion and working of biofuels.

Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide.

Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

Synthesis of Sunflower Oil Based Elastomer and Its Characterization by Using Spectroscopic Techniques

SummaryA new elastomer was successfully materialized from sunflower oil (a vegetable oil). The reaction was confirmed by Fourier Transform Infrared (FTIR) and Fourier Transform Nuclear Magnetic Resonance (FTNMR) methods. FTIR analysis indicated that amine functional groups appear at 3325 cm−1 representing N‐H stretching of primary and secondary amines and at 1645 cm−1 representing N‐H deformation of primary amines. The hydrogen bonding was confirmed with the appearance a broad peak in the region 2500–3800 cm−1. FTNMR analysis also show the appearance amine functional groups at peak 5.4 ppm in 1H NMR representing proton in amine functional groups and peaks at 151 ppm and 156.6 ppm in 13C NMR representing carbon in amine functional groups.

Influence of ethanol concentration and temperature on antioxidant and antibacterial activity from Artocarpus altilis (Parkinson) Fosberg leaves

Objective: Artocarpus altilis or Sukun is one kind of herbal medicine that is usually used by Indonesian people. It is widely known that the flavonoid derivative of A.altilis, one of its major bioactive constituent, has a broad range of pharmacological activity such as antioxidant, antibacterial, anti-inflamantory, antidiabetic and many others. In this study we investigated the bioactive constituent and influence of ethanol concentration, time and temperature on the antioxidant and antibacterial activity of A.altilis leaves in order to find appropriate and effective condition for its extraction. Methods: A.altilis leaves were extracted with different ethanol concentration (50, 60 and 70% v/v), time (1, 2, 3, 4 and 24 h) and temperature (70oC and room temperature). Influence of different extraction processes was analyzed on antioxidant capacity, antibacterial activity, total phenolic and total flavonoid content. Isolation of bioactive compound was performed by column chromatography method and structure was elucidated by 1H and 13C FT-NMR (Fourier Transform-Nuclear Magnetic Resonance) spectra. Results: Concentration of 70% v/v ethanol, 70oC and 1 h extraction process were found to be the most appropriate condition for extraction of A.altilis leaves in order to obtain bioactive components which gave both antioxidant and antibacterial activity against E.coli while yield of total flavonoid and phenolic content of extract should not less than 1.9 and 1.8% w/w, respectively. Structure elucidation of isolated compound identified that prenylated flavonoid, i.e. 1-(2,4-dihydroxyphenyl)-3-(8-hydroxy-2-methyl-2-(4-methylpent-3-en-1-yl)-2H-chromen-5-yl)propa-1-one is one of its important bioactive constituent. Conclusion: Use of ethanol concentration, temperature and time influenced the yield of total phenolic and flavonoid content and bioactivity of A.altilis extract. It is recommended to heat the extraction process to 70oC in order to obtain both optimal antioxidant and antibacterial activity from ethanol extract of A.altilis leaves.

Fast Synthesis of High Quality Biodiesel from ‘Waste Fish Oil’ by Single Step Transesterification

A large volume of fish wastes is produced on a daily basis in the Indian sub-continent. This abundant waste source could serve as an economic feedstock for bioenergy generation. In the present study, oil extracted from discarded fish parts was used for high quality biodiesel production. More specifically, a single step transesterification of ‘waste fishoil’ with methanol using sodium methoxide (CH3ONa) as homogeneous catalyst under moderate operational conditions resulted in highly pure biodiesel of > 98% of fatty acid methyl ester (FAME) content. Characterization was performed by Fourier Transform-Nuclear Magnetic Resonance (FT-NMR).

Cloning and characterisation of a novel neoagarotetraose-forming-β-agarase, AgWH50A from Agarivorans gilvus WH0801

AgWH50A, a novel β-agarase, was cloned from Agarivorans gilvus WH0801 by degenerate and nested PCR. It consists of 942 amino acids (105kDa), including a 21-amino acid signal peptide. AgWH50A shares the highest amino acid sequence homology with AgaD02 from Agarivorans sp. QM38 (53%). The recombinant agarase gene was expressed in Escherichia coli and purified by affinity chromatography. Maximum enzymatic activity (Km 5.97mg/mL and Vmax 0.781U/mg) was observed at pH 6.0 and 30°C. Using matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry, Fourier transform-nuclear magnetic resonance spectrometry and thin-layer chromatography, we analysed the hydrolysis products and concluded that AgWH50A is a neoagarotetraose-forming β-agarase, which can cleave agarose into neoagarotetraose. This novel agarase has potential applications in the industrial production of neoagarotetraose and provides a new agarose hydrolysis model for future research.