We report on the cloning of the lipase gene from Bacillus licheniformis IBRLCHS2
and the expression of the recombinant lipase. DNA sequencing analysis of the
cloned lipase gene showed that it shares 99% identity with the lipase gene from
B. licheniformis ATCC 14580 and belongs to subfamily 1.4 of true lipases based on amino
acid sequence alignment of various Bacillus lipases. The 612 bp lipase gene was then
cloned into the pET-15b(+) expression vector and the construct was transformed into
E. coli BL21 (DE3) for bulk expression of the lipase. Expression was analysed by SDSPAGE
where the lipase was found to have a molecular weight of about 23 kDa.
The effects of flow rate, different pressures and temperatures on cocoa butter extracted from cocoa nib using supercritical carbon dioxide (scCO2) were investigated. The yield was analyzed for total fat content, triacylglycerol (TG) profile, and fatty acid (FA) profile. Extractions were carried out at pressures of 20 and 35 MPa, temperatures of 50 and 60 °C, and CO2 flow rates of 0.5, 1, 2, 4 mL min(-1). The result shows that the yield of cocoa butter extract increased with increasing pressure, temperature, and flow rate and the optimum conditions for the maximum cocoa butter extraction were 35 MPa, 60 °C and 2 mL min(-1), repectively. TGs and FAs were found to be similar in composition to those of cocoa butter obtained by conventional methods. The lower molecular weight TGs and FAs showed higher selectivity compared to higher molecular weight TGs and FAs.
Human saliva contains a large number of proteins which can be separated using polyacrylamide gel electrophoresis (PAGE). In this study the protein profiles of whole saliva of diabetic and non-diabetic were compared. Considerable variations between individuals in the protein profiles were observed. The saliva from diabetic patients appeared to have more of proline-rich protein bands in the molecular weight region below 56 KOa. Further investigations using individual gland saliva should be carried out.
Solvent flow reactor system was introduced into the extraction system to increase the system efficiency and enhance the extraction yield by adding fresh solvent during the extraction processes. The liquefaction experiment was carried out at various flow-rates (1, 3 and 5 ml/min), reaction times (30, 45 and 60 min) and reaction temperatures (300ºC, 350ºC, 400ºC, 420ºC and 450ºC) with tetralin as solvent. Despite the ability of adding fresh solvent into the extraction process, the conversion of oil+gas was still considered to be low as there was ~25% of coal extracts left to be converted into low molecular weight compounds. One possible option to increase the oil yield is by applying catalyst that will further break up the coal extracts into small molecular weight compounds. In this study, a second reactor was introduced consisting of catalyst (NiSiO2) assuming that the catalyst would interact more effectively with coal extracts rather than the coal itself. In the
absence of catalyst, the oil yield was 55%. By introducing the Ni catalyst, the oil yield increased by 15%. Further analysis of GCMS showed that the oil from catalytic liquefaction gave out more low molecular weight compounds in comparison to the un-catalytic liquefaction oil.
Various palm oil (RBD Palm Olein) based urethane acrylate prepolymers (UPs) having different structures and molecular weights were synthesised from palm oil based polyols, diisocyanate compounds and hydroxyl terminated acrylate monomers by following established synthesis procedures described elsewhere. The products (UPs) were compared with each other in terms of their molecular weights (MW), viscosities and UV curing performances of pressure sensitive adhesives (PSA) UP based formulations. The molecular structure of diisocyanate compounds and hydroxyl acrylate monomers tend to determine the molecular weights and hence viscosities of the final products of urethane acrylate prepolymers (UP), whereas, the MW of the UP has no direct effects on the coatings and adhesive properties of UV curable UP based PSA.
The aim of this study is to investigate the effect of pH levels on functional properties of various molecular weights of eel (Monopterus sp.) protein hydrolysate (EPH). The eel was enzymatically hydrolyzed and fractionated through membranes filter (10 kDa, 5 kDa and 3 kDa). The foaming capacity and stability, emulsifying capacity and stability index, water holding capacity and fat binding capacity between pH 2 and 10 were determined. The 5 kDa EPH was found to have the highest foaming capacity at pH 2, pH 4 and pH 6, and foaming stability and emulsifying activity index at all pH levels, except pH 8 and fat binding capacity at pH 2, as compared to 10 kDa and 3 kDa EPH fractions. The 10 kDa EPH had the highest emulsifying stability index and water holding capacity at all pH levels. This study shows that the EPH fractions at low pH level had high foaming and oil binding capacity, while at neutral pH, the fractions had high foaming stability and water holding capacity. These properties are important in making whipped cream, mousse and meringue. In contrast, EPH fractions demonstrated strong emulsifying properties at high pH levels and show potential as an emulsifier for breads, biscuits and frozen desserts.
Molybdenum is an emerging pollutant. Bioremediation of this heavy metal is possible by the
mediation of Mo-reducing bacteria. These bacteria contain the Mo-reducing enzymes that can
conver toxic soluble molybdenum into molybdenum blue; a less soluble and less toxic form of the
metal. To date only the enzyme has been purified from only one bacterium. The aim of this study is
to purify the Mo-reducing enzyme from a previously isolated Mo-reducing bacterium Bacillus
pumilus strain Lbna using ammonium sulphate fractionation followed by ion exchange and then
gel filtration. Two clear bands were obtained after the gel filtration step with molecular weights
of 70 and 100 kDa. This indicates that further additional purification methods need to be used
to get a purified fraction. Hence, additional steps of chromatography such as hydroxyapatite or
chromatofocusing techniques can be applied in the future.
A search for a light charged Higgs boson (H^{+}) decaying to a W boson and a CP-odd Higgs boson (A) in final states with eμμ or μμμ is performed using data from pp collisions at sqrt[s]=13 TeV, recorded by the CMS detector at the LHC and corresponding to an integrated luminosity of 35.9 fb^{-1}. In this search, it is assumed that the H^{+} boson is produced in decays of top quarks, and the A boson decays to two oppositely charged muons. The presence of signals for H^{+} boson masses between 100 and 160 GeV and A boson masses between 15 and 75 GeV is investigated. No evidence for the production of the H^{+} boson is found. Upper limits at 95% confidence level are obtained on the combined branching fraction for the decay chain, t→bH^{+}→bW^{+}A→bW^{+}μ^{+}μ^{-}, of 1.9×10^{-6} to 8.6×10^{-6}, depending on the masses of the H^{+} and A bosons. These are the first limits for these decay modes of the H^{+} and A bosons.
The effect of adding aluminum hydroxide (ATH) in the palm-based polyurethane hybrid composite was studied. The compression stress and modulus, thermal conductivity and acoustic property were determined. The hybrid composite was prepared by adding 10 wt% of oil palm empty fruit bunch fibre (EFB) followed by ATH at varying amount of 2, 4 and 6 wt% of the overall mass of the resin. The compression stress and modulus gave the highest values of 575 kPa and 2301 kPa, respectively at 2 wt% ATH. At 4 wt% ATH, the compression stress and modulus decreased to 431 kPa and 1659 kPa, respectively and further decreased at 6 wt% ATH to 339 kPa and 1468 kPa respectively. The k-value increased with the increment of the ATH loading exhibited a poor thermal conductivity. Sound absorption analysis indicated that the absorption coefficient was higher at higher frequency (4000 Hz) for all samples with PU-EFB/ATH with 4% ATH showed the highest absorption coefficient.
Poly(N-isopropylacrylamide) (PNIPA) brushes on silicon substrate was constructed and molecular weight and polydispersity index was controlled precisely. Molecular behavior of the PNIPA grafted surface was observed by using captive bubble contact angle method. A very interesting phenomenon of high density PNIPA grafted membrane with a chloride terminal molecule was observed. The contact angle of high density PNIPA-Cl increased sharply while the temperature rises above 32oC. But in the case of PNIPA gel surface the contact angle result decreases sharply while the temperature reaches above lower critical solution temperature (LCST). In order to identify the reason behind this abnormal behavior of PNIPA-Cl grafted membrane, the terminal chloride molecule of PNIPA chain was modified to less electronegative azide (-N3) as well as carboxylic acid (-COOH). Finally it was found that terminal molecule of high density PNIPA grafted membrane has a great influences on the wettability change of PNIPA membrane in water by changing the temperature.
Bio-novolac fibre made from phenol-formaldehyde derived oil palm empty fruit bunch (EFB) was produced using electrospinning method. The bio-novolac phenol-formaldehyde was prepared via liquefaction and resinification at two different molar ratios of formaldehyde to liquefied EFB (LEFB) (F:LEFB = 0.5:1 and 0.8:1). Electrospinning was applied to the bio-novolac phenol-formaldehyde (BPF) in order to form smooth and thin as-spun fibre. The BPF was electrospun at 15 kV and 15 cm distance between needle and collector at a flow rate of 0.5 mL/h. At lower molecular weight of BPF resin, beads formation was observed. The addition of poly(vinyl) butyral (Mw = 175,000 - 250,000) has improved the fibre formation with lesser beads hence produced more fibre. Polymer solution with higher molecular weight produced better quality fibre.
Enzymatic hydrolysis of proteins is an important bioprocess method to prepare bioactive peptides with many functionality and health benefits. The aims of the present work were to prepare and determine the physicochemical characteristics of gelatine hydrolysate from skin of shortfin scad (SSGH) via hydrolysis using alcalase. Analyses on chemical composition, molecular weight by SDS PAGE, protein concentration, amino acid composition, Fourier Transform Infrared Spectroscopic features, and solubility of SSGH were thus performed. The yield of SSGH obtained was 51.01% (d.b.). The chemical compositions of SSGH for moisture, protein, fat, and ash were 13.82%, 90.05%, 1.95%, and 12.48%, respectively. SSGH showed low molecular weight (
The individual compounds and sources of polycyclic aromatic hydrocarbon (PAHs) were studied in the surface sediments
at 32 locations in the tourism area of Langkawi Island. A total of 15 PAHs were determined and quantified by gas
chromatography coupled with mass spectrometry (GC-MS). The total PAH concentrations of surface sediments from
Langkawi Island ranged from 228.13 to 990.25 ng/g and they were classified as being in the low to moderate pollution
range. All sampling stations were dominated by high molecular weight PAHs with 4 rings (31.59%) and 5-6 rings (42.73%).
The diagnostic ratio results showed that in most cases, the sampling stations have pyrogenic input. Further analysis
using principal component analysis (PCA) combined with absolute principal component score (APCS) and multiple linear
regression (MLR) showed that the natural gas emissions contributed to 57% of the total PAH concentration, 22% from the
incomplete combustion and pyrolysis of fuel, 15% from pyrogenic and petrogenic sources and 6% from an undefined source.
This study investigated the effect of manufacturing process variables of mini-tablets, in particular, the effect of process variables concerning fluidized bed granulation on tablet weight variation. Test granules were produced with different granulation conditions according to a definitive screening design (DSD). The five evaluated factors assigned to DSD were: the grinding speed of the sample mill at the grinding process of the active pharmaceutical ingredient (X1), microcrystalline cellulose content in granules (X2), inlet air temperature (X3), binder concentration (X4) and the spray speed of the binder solution (X5) at the granulation process. First, the relationships between the evaluated factors and the granule properties were investigated. As a result of the DSD analysis, the mode of action of granulation parameters on the granule properties was fully characterized. Subsequently, the variation in tablet weight was examined. In addition to mini-tablets (3 mm diameter), this experiment assessed regular tablets (8 mm diameter). From the results for regular tablets, the variation in tablet weight was affected by the flowability of granules. By contrast, regarding the mini-tablets, no significant effect on the variation of tablet weight was found from the evaluated factors. From this result, this study further focused on other important factors besides the granulation process, and then the effect of the die-hole position of the multiple-tip tooling on tablet weight variation was proven to be significant. Our findings provide a better understanding of manufacturing mini-tablets.
The effects of human cytomegalovirus (HCMV) infection on human fibroblast cell genomes were investigated using agarose gel electrophoresis. At selected intervals post-infection (PI), cellular D N A from mock-treated and HCMV-infected cells were prepared in low melting point agarose plugs. Results obtained following electrophoresis of the cellular D N A indicate that HCMV infection did not result in extensive degradation of the cellular DNA, even in samples obtained from cells which showed > 95% cytopathologic effects. High molecular weight DNA (> 23 Kb) comparable to that of the mock-treated samples were noted in a l l HCMV infected DNA samples. Digestion of the DNA samples with restriction endonucleases, EcoR I, Not I, Sfi I, and Nru I, however, resulted in the appearance of smaller DNA fragments (< 23 Kb) in samples obtained on day 3, 4, and 5 PI. Since these DNA bands appeared only in the infected cells, it was likely that these were the HCMV genomic DNA fragments. Findings presented in this study support the notion that the cellular DNA of HCMVinfected cells could remained intact and functiona. KEYWORDS: Cytomegalovirus, chromosomes, DNA, genomes, restriction enzymes
50 years ago, Karl Ziegler and Giulio Natta were awarded the Nobel Prize for their discovery of the catalytic polymerization of ethylene and propylene using titanium compounds and aluminum-alkyls as co-catalysts. Polyolefins have grown to become one of the biggest of all produced polymers. New metallocene/methylaluminoxane (MAO) catalysts open the possibility to synthesize polymers with highly defined microstructure, tacticity, and steroregularity, as well as long-chain branched, or blocky copolymers with excellent properties. This improvement in polymerization is possible due to the single active sites available on the metallocene catalysts in contrast to their traditional counterparts. Moreover, these catalysts, half titanocenes/MAO, zirconocenes, and other single site catalysts can control various important parameters, such as co-monomer distribution, molecular weight, molecular weight distribution, molecular architecture, stereo-specificity, degree of linearity, and branching of the polymer. However, in most cases research in this area has reduced academia as olefin polymerization has seen significant advancements in the industries. Therefore, this paper aims to further motivate interest in polyolefin research in academia by highlighting promising and open areas for the future.
Arabinoxylans (AXs) are major dietary fibre in cereals. Recently, AXs have attracted a great deal of attention because of their biological activities. These activities have been suggested to be related to the content of low molecular weight (Mw) AXs, in particular those with Mw below 32 kDa. Rice bran is a rich source of AXs. However, water extraction of AXs is difficult and often gives low yield. Extrusion processing has been used to increase the solubility of cereal dietary fibre. The aim of this research was to study the effect of extrusion screw-speeds (80 and 160) rpm on the extraction yield and Mw of water extractable AXs from rice bran. It was found that the extraction of AXs increased significantly with an increase in screw speed and was accompanied by a significant decrease in the Mw of AXs from extruded rice bran. The percentage of very low molecular weight AXs (0.79-1.58 kDa) significantly increased with increasing screw speed.
Konjac glucomannan (KGM) was treated with or without sonication and/or hydrochloric acid (HCl).
Hydrolysis effects on KGM were studied for properties such as degree of hydrolysis, fluidity, molecular mass, and creep properties. The degree of hydrolysis for sonicated KGM and acid treated KGM were not significantly different. However, the combination treatment of acid hydrolysis and sonication was found effective in yielding a smaller molecular weight fraction of KGM and solution with higher fluidity. From the creep analysis, KGM treated with combination treatment exhibited the highest compliance among samples tested. In general, ultrasound mediated acid hydrolysis was found to be a promising technique in degrading high molecular weight biopolymer. This could be attributed to a localized high temperature and high shear forces generated during cavitation that facilitated the endothermic acid hydrolysis.
The properties of collagens from Barramundi (Lates calcarifer) skin obtained by acid solubilized (control), pepsin and papain aided extractions were investigated. The yields of collagens (dry weight basis) for acid solubilized, pepsin and papain aided extractions were 8.1, 43.6 and 44.0%, respectively. The collagens were generally colorless although collagens from the enzymes aided-extractions were slightly darker. Based on the e-nose evaluation, the collagens were considered odorless. The pH of all the collagens was in the vicinity of 3; however, those extracted with papain had significantly higher pH. The polypeptide profiles obtained in the SDS-PAGE analysis for pepsin extracted collagen were similar to those of acid solubilized collagens. Papain extracted collagen had distinctly different SDS-PAGE pattern. All the extracted collagens were of type 1 with apparent peptides molecular weight distribution of 37 to 250 kDalton. They had high solubility in pH 2 to 5 and increasing NaCl concentration up to 6%.
Microbial arsenite oxidation is an essential biogeochemical process whereby more toxic arsenite is oxidized to the less toxic arsenate. Thiomonas strains represent an important arsenite oxidizer found ubiquitous in acid mine drainage. In the present study, the arsenite oxidase gene (aioBA) was cloned from Thiomonas delicata DSM 16361, expressed heterologously in E. coli and purified to homogeneity. The purified recombinant Aio consisted of two subunits with the respective molecular weights of 91 and 21 kDa according to SDS-PAGE. Aio catalysis was optimum at pH 5.5 and 50-55 °C. Aio exhibited stability under acidic conditions (pH 2.5-6). The V max and K m values of the enzyme were found to be 4 µmol min(-1) mg(-1) and 14.2 µM, respectively. SDS and Triton X-100 were found to inhibit the enzyme activity. The homology model of Aio showed correlation with the acidophilic adaptation of the enzyme. This is the first characterization studies of Aio from a species belonging to the Thiomonas genus. The arsenite oxidase was found to be among the acid-tolerant Aio reported to date and has the potential to be used for biosensor and bioremediation applications in acidic environments.