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Endo-1,4-β-xylanase catalyzes the random hydrolysis of β-1,4-D-xylosidic bonds in xylan, resulting in the formation of oligomers of xylose. This study aims to demonstrate the promise of endoxylanases from alkaliphilic Bacillus halodurans for the production of xylooligosaccharides (XOS) from oil palm empty fruit bunch (EFB) at high pH. Two enzyme preparations were employed: recombinant endoxylanase Xyn45 (GH10 xylanase) and nonrecombinant endoxylanases, a mixture of two extracellular endo-1,4-β-xylanases Xyn45 and Xyn23 (GH11 xylanase) produced by B. halodurans. EFB was first treated with an alkaline solution. Then, the dissolved xylan-containing fraction was retained, and a prepared enzyme was added to react at pH 8 to convert xylan into XOS. Compared with the use of only Xyn45, the combined use of Xyn45 and Xyn23 resulted in a higher yield of XOS, suggesting the synergistic effect of the two endoxylanases. The yield of XOS obtained from EFB was as high as 46.77% ± 1.64% (w/w), with the xylobiose-to-xylotriose ratio being 6:5. However, when the enzyme activity dose was low, the product contained more xylotriose than xylobiose. Four probiotic lactobacilli and bifidobacteria grew well on a medium containing XOS from EFB. The presence of XOS increased cell mass and reduced pH, suggesting that XOS promoted the growth of probiotics.

Water uptake properties of organic matter (OM) are critical for aerosol direct and indirect effects. OM contains various chemical species that have a wide range of water solubility. However, the role of water solubility on water uptake by OM has poorly been investigated. We experimentally retrieved water solubility distributions of water-soluble OM (WSOM) from combustion of mosquito coil and tropical peat using the 1-octanol-water partitioning method. In addition, hygroscopic growth and cloud condensation nuclei (CCN) activity of solubility-segregated WSOM were measured. The dominant fraction of WSOM from mosquito coil smoldering was highly soluble (water solubility (

In this study, expired egg white was used as a template, and a sol–gel method was employed to prepare pure-phase TiO2 nano-powder and mixed-phase powders doped with NaF and NaI. The influences of different calcination temperatures, doping elements, and doping amounts during the preparation process on the photocatalytic performance and activity of the prepared TiO2 powders were studied. The results of the experiments showed that the F-doped TiO2 had the highest photocatalytic activity when the doping amount was 1.2%, as examined by EDS, where the sintering temperature was 500 °C. F-doped TiO2 nanoparticles were also synthesized by the sol–gel method using tetrabutyl titanate and NaF mixed with expired egg white protein as the precursor. The F-TiO2 photocatalyst was characterized using FE-SEM, HR-TEM, EDS, XPS, and UV-Vis, and the photocatalytic activity was evaluated by photodegradation of methylene blue under visible light. The results showed that doping with F reduced the energy band gap (3.04 eV) of TiO2, thereby increasing the photocatalytic activity in the visible-light region. The visible-light wavelength range and photocatalytic activity of the catalyst were also affected by the doping amount.

This study aims to compare and analyze the chemical structures of bacterial biosurfactants produced by an indigenous Bacillus subtillis strain cultured in minimal salt medium (MSM) enriched with fresh cooking oil and used cooking oils that are cheaper and easy to obtained in huge quantities. Optimization of biosurfactants was successfully conducted in two MSMs enriched with 2% (v/v) fresh cooking oil and 2% (v/v) waste cooking oil respectively. The initial pH of growth medium was fixed at pH 7.64 and the whole fermentation process was maintained in a constant temperature of 30 °C. Chemical structures analysis of biosurfactants produced at 1L scale in bioreactor were conducted using spectroscopic methods such as Nuclear Magnetic Resonance (NMR) and Fourier-Transform Infrared spectroscopy (FTIR). The chemical compound isolated from the biosurfactant produced from the waste cooking oil was pentyl 2-ureidobut-3-enoate (1) while (1-hydroxyethyl)amino)methyl heptanoate (2) was isolated from the biosurfactant produced from fresh cooking oil. This study demonstrated the ability of Bacillus subtilis to produce a low-cost biosurfactant characterized as lipopeptide.

Experimental data of ethanol fermentation in a two-tank system with cell recycling using sucrose as a substrate were investigated to establish a kinetic model that described the reaction. Flocculent yeast Saccharomyces diastaticus LORRE-316 was used as the fermenting yeast, and the fermentation medium comprised 80 g/L sucrose, 10 g/L yeast extract, 10 g/L peptone, 2 g/L potassium phosphate monobasic (KH2PO4), and 0.5 g/L magnesium sulfate heptahydrate (MgSO4·7H2O). Three models, the Monod model, the modified Monod model, and the extended-modified Monod model, were used to describe fermentation, and the extended-modified Monod model described the reaction more accurately than the other two models. The model took substrate limitations plus substrate and ethanol inhibitive effects into consideration, and was modified to include assumptions that included terms for substrates (sucrose, glucose and fructose) and product (ethanol). In addition, the ethanol concentration had a significant effect on cell growth. The results of Lineweaver–Burk plots showed that the maximum specific growth rate (μMAX) and the Monod constant (KS) were 0.72/h and 26.77 g/L, respectively. The models were suitable for describing the experimental data.

Fluoride contamination in water due to natural and anthropogenic activities has been documented as serious problems worldwide commanding a major threat to the environment. Present study focuses to synthesis bacterial-surfactin ( Bacillus subtilis ) mediated nano-hydroxyapatite (HAp), novel adsorbents for defluoridation. HAp particle size and morphology were controlled by varying temperature of 90–150 °C and pH of 7–11, respectively. The TEM and SEM micrographs reveal that the short-rod particle is observed 20–30 nm at 90 °C and pH 11. The ratio between the length (nm) and width (nm) of nanoparticle are decreased from 4.17 to 1.65 with increasing pH (7–11). The selected area diffraction (SAD) of particles are indicated uniform rod-like monocrystals. The XRD and FTIR observations were indicated the synthesized HAp nanoparticles were well-crystallized with purity phase and high quality. The study reflected that the fluoride removal from contaminated water by HAp was increased significantly (R 2 = 99) with the increasing adsorbent concentration, temperature and time, with two-step adsorption process as the first portion a rapid adsorption occurs during first 90 min after which equilibrium is slowly achieved. The adsorption process is closer to Freundlich isotherm (R 2 > 98) than to Langmuir isotherm (R 2 ≈ 92), indicating HAp as a good adsorbent (n > 3). Above 97% of fluoride removal were noticed at a HAp dose of 0.06 g/10 mL. The adsorption kinetics more fit with pseudo-second-order (R 2 = 99) in compare to pseudo-first-order (R 2 ≈ 91). The slope and intercept of Arrhenius equation indicated the activation/adsorption energy (E a ) of 3.199 kJ/mol and frequency factor (A) of 1.78 1/s. Adsorption thermodynamic parameters (free energy (ΔG 0) and entropy (ΔS > 0)) indicates the spontaneous and endothermic reactions of the adsorption process. Thus, newly synthesized HAp nanoparticles exhibit as a good adsorbent for fluoride removal, theoretically and experimentally being applicable for environmental pollution control.

Cobalt oxide (Co3O4) has received great attention for its use in diverse applications in science and technology. The synthesis Co3O4 by ecofriendly green technological process is the great challenge in present day research.Considering the ecofriendly green technological application, the nano-Co3O4 has been synthesized by microbial induced precipitation (MIP) process in presence of Bacillus pasteurii (OD600; 1.2 × 107cells/mL). The Co3O4 particle was synthesized with different microbial amount (10–30 mL) and Co(NO3)2 (0.01M-1.0 M) by MIP process.The results were exhibited anoptimum yield (production yield 218 mg and conversion yield 61%) of “hybrid bio-Cobalt compound”formation at 0.1 M Cobalt ion and 30 mL of B. pasteurii. The XRD results reflect the formation of Co3O4 from “hybrid bio-Cobalt compound” after calcination at 550 °C. SEM and TEM micrograph of synthesized particle reflects the non-specific shape of particle size range at 10–31 nm. The electrochemical capacitive performance was studied through cyclic voltammetry (CV) and galvanostatic charge–discharge methods with 6.0 M KOH as electrolyte. The synthesized nano-Co3O4 after calcinated at 550 °C, leads to the best specific capacitance of 162.78 F g−1 at 1 mA cm−2constant current density. The energy density and power density of the synthesized were noticed as 4.58 Wh kg−1 and 64.29 W kg−1, respectively, which indicates the MIP synthesized nano-Co3O4 particle is supercapacitor. Thus, MIP process, an ecofriendly green technological process is capable to synthesized the supercapacitor nano-Co3O4 by Bacillus pasteurii and its can be applicable to energy and environment research sector.

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112 kDa with optimal pH value and temperature measured of 7.0 and 40 °C, respectively. It was stable at a pH range of 6.0–7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba2+, Al3+, and Co2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2 g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10 g/L cassava starch as the sole carbon source when cultivated at 37 °C for 48 h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150 g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.

Water-soluble organic matters (WSOMs) play an important role in determining magnitudes of climatic and environmental impacts of organic aerosol particles because of their contributions to hygroscopic growth and cloud formation. These processes are dependent on water solubility as well as distribution of this property in a particle, yet no method has been available to quantify such characteristics. In this study, we developed a theoretical framework to classify WSOM by 1-octanol-water partitioning that has a strong correlation with water solubility. 1-octanol-water partitioning coefficient also has a strong correlation with a traditional solid phase extraction method, facilitating interpretation of data from the technique. The theoretical analysis demonstrated that the distributions of WSOM classified by 1-octanol-water partitioning depend on (1) the volume ratio of 1-octanol and aqueous phases, and (2) extraction steps. The method was tested by using organic aerosol particles generated by smoldering of a mosquito coil, which serves as a surrogate for biomass burning particles. The WSOM extracted from the mosquito coil burning particles was classified by 1-octanol-water partitioning at different volume ratios. These solutions, including both the 1-octanol and aqueous phases, were nebulized to generate particles for measurements using an online aerosol mass spectrometer. The mass spectra indicated that highly oxygenated species tend to be highly soluble, while high molecular weight compounds are less soluble. Linear combinations of these mass spectra allowed the estimation of the mass fractions of WSOM partitioned to 1-octanol and aqueous phases, thereby facilitating the evaluation of the mass fractions of cloud condensation nuclei (CCN) active materials. NRF (Natl Research Foundation, S’pore) Accepted version

The polarity distribution of water-soluble organic matter (WSOM) is believed to play an important role in determining the water uptake properties of aerosol particles. The 1-octanol−water partitioning method has been proposed as a method for classifying WSOM by polarity. However, the broad partitioning functions of the method make it difficult to estimate polarity distribution. In this study, a data inversion technique was developed to determine the polarity distributions of WSOM. The inversion technique was evaluated against artificially generated polarity distributions with corresponding uncertainties. In addition, the technique was combined with positive matrix factorization (PMF) analysis of the aerosol mass spectrometric data, allowing an estimation of the polarity distribution of the PMF factors. The technique was applied to WSOM generated by smoldering mosquito coils. As the 1-octanol−water partitioning coefficients of WSOM correlate well with water solubility, future application of this method to the investigation of hygroscopic growth and cloud condensation nucleus (CCN) activity will help to quantitatively connect the chemical characteristics and water uptake properties of WSOM. Copyright © 2020 American Association for Aerosol Research

Polarity distribution of water-soluble organic matter (WSOM) is an important factor in determining the hygroscopic and cloud nucleation abilities of organic aerosol particles. We applied a novel framework to quantitatively classify WSOM based on the 1-octanol-water partition coefficient (KOW), which often serves as a proxy of polarity. In this study, WSOM was generated in a laboratory biomass-burning experiment by smoldering of Indonesian peat and vegetation samples. The fractionated WSOM was analyzed using a UV-visible spectrophotometer, spectrofluorometer, and time-of-flight aerosol chemical speciation monitor. Several deconvolution methods, including positive matrix factorization, parallel factor analysis, and least-squares analysis, were applied to the measured spectra, resulting in three classes of WSOM. The highly polar fraction of WSOM, which predominantly exists in the range of log KOW < 0, is highly oxygenated and exhibits similar optical properties as those of light-absorbing humic-like substances (HULIS, termed after the humic substances due to the similarity in chemical characteristics). WSOM in the least-polar fraction, which mainly distributes in log KOW > 1, mostly consists of hydrocarbon-like and high molecular weight species. In between the most- and least-polar fraction, WSOM in the marginally polar fraction likely contains aromatic compounds. The analyses have also suggested the existence of HULIS with different polarities. Comparison with previous studies indicates that only WSOM in the highly polar fraction (log KOW < 0) likely contributes to water uptake. Nanyang Technological University National Research Foundation (NRF) We acknowledge Patrick Martin for permitting us to use the UV–vis and fluorescence spectrometers. We thank Yongli Zhou, Ashleen S. Y. Tan, and Liudongqing Yang for assistance with the UV–vis and fluorescence measurement, Xin Wang for designing the graphical abstract, and Pavel Adamek for English editing. We also thank Dr. Haris Gunawan for supporting sample collection in Indonesia. This research was supported by the National Research Foundation Singapore under its Singapore NRF Fellowship scheme (National Research Fellow Award, NRF2012NRF-NRFF001-031), NRF Campus for Research Excellence and Technological Enterprise (CREATE) Programme, the Earth Observatory of Singapore (EOS), Nanyang Technological University, and the Research Institute for Humanity and Nature (RIHN) (Project ID 14200117).

Magnetic nanoparticles bound with glutathione (GSH) are useful for diagnostics, enzyme immobilization, and affinity precipitation by using the strong and specific interaction of GSH with glutathione S-transferase (GST)-fused proteins. Our studies revealed that GSH-bound magnetic nanoparticles could be obtained using the covalent bond linkage of GSH and nanoparticles to promote the stability of bound GSH. To yield this conjugate, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared and modified using tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), which introduced amino groups that were then activated with maleic anhydride (MA) for covalent binding of GSH. After MA was used to activate the amino-grafted SPION for 24 h, the yield of GSH conjugation increased over 4 days from 37 % to 74 % of the original amine density on the surface as the incubation of GSH with MA-activated SPION. These GSH-bound magnetic nanoparticles, designated as SPION@silica-GSH with approximately 103 nmol GSH/mg particles, were ready for coupling with GST-fused protein through the GSH-GST affinity interaction. A GST-tagged small fragment of ubiquitin-like-specific protease 1 (sfULP1) was used as the model protein for immobilization on SPION@silica-GSH. ULP1 is a small ubiquitin-like modifier (SUMO) protease. Results indicated that this immobilized GST-sfULP1 could retain 87 % ± 5 % enzyme activity of free protease before immobilization and could catalyze the cleavage of the SUMO-fused peptide (SUMO-GLP-1) to obtain glucagon-like peptide-1, a peptide hormone for type 2 diabetes therapy.

Xylitol production from xylose by the yeast Candida magnoliae TISTR 5663 was enhanced by supplementing the fermentation medium with furfural (300mg/L) and glucose (3g/L with an initial mass ratio of glucose to xylose of 1:10) together under oxygen limiting conditions. In the presence of furfural and glucose, the final concentration of xylitol was unaffected relative to control cultures but the xylitol yield on xylose increased by about 5%. Supplementation of the culture medium with glucose alone at an initial concentration of 3g/L, stimulated the volumetric and specific rates of xylose consumption and the rate of xylitol production from xylose. In a culture medium containing 30g/L xylose, 300mg/L furfural and 3g/L glucose, the volumetric production rate of xylitol was 1.04g/L h and the specific production rate was 0.169g/g h. In the absence of furfural and glucose, the volumetric production rate of xylitol was ∼35% lower and the specific production rate was nearly 30% lower. In view of these results, xylose-containing lignocellulosic hydrolysates contaminated with furfural can be effectively used for producing xylitol by fermentation so long as the glucose-to-xylose mass ratio in the hydrolysate does not exceed 1:10 and the furfural concentration is ≤300mg/L.

Cassava waste pulp (CWP)–enzymatic hydrolysate was co-fermented with molasses (CWP-EH/molasses mixture) with the aim to optimize ethanol production by Saccharomyces cerevisiae TISTR 5606 (SC 90). The optimal fermentation conditions for ethanol production using this mixture were 245 g/L initial total sugar supplemented with KH2PO4 (8 g/L), at 30 °C for 48 h of fermentation under an oxygen-limited condition with agitation at 100 rpm, producing an ethanol concentration of 70.60 g/L (0.31 g ethanol/g total sugar). The addition of cassava tuber fiber (solid residue of CWP after enzymatic hydrolysis) at 30 g/L dry weight to the CWP-EH/molasses mixture increased ethanol production to 74.36 g/L (0.32 g ethanol/g total sugar). Co-fermentation of CWP-EH with molasses had the advantage of not requiring any supplementation of the fermentation mixture with reduced nitrogen.

The production of ethanol from the fast-growing perennial C4 grass Miscanthus floridulus by simultaneous saccharification and fermentation (SSF) was investigated. M. floridulus biomass was composed of 36.3% glucan, 22.8% hemicellulose, and 21.3% lignin (based on dried mass). Prior to SSF, harvested stems of M. floridulus were pretreated separately by alkali treatment at room temperature, alkali treatment at 90 °C, steam explosion, and acid-catalyzed steam explosion. The delignification rates were determined to be 73.7%, 61.5%, 42.7%, and 63.5%, respectively, by these four methods, and the hemicellulose removal rates were 51.5%, 85.1%, 70.5%, and 97.3%, respectively. SSF of residual solids after various pretreatments was performed with dried yeast (Saccharomyces cerevisiae) and cellulases (Accellerase 1000) by using 10% water-insoluble solids (WIS) of the pretreated M. floridulus as the substrate. The ethanol yields from 72-h SSF of M. floridulus biomass after these pretreatments were 48.9 ± 3.5, 78.4 ± 1.0, 46.4 ± 0.1, and 69.0 ± 0.1% (w/w), respectively, while the ethanol concentrations after 72-h SSF were determined to be 15.4 ± 1.1, 27.5 ± 0.3, 13.9 ± 0.1, and 30.8 ± 0.1 g/L, respectively. Overall, the highest amount of ethanol (0.124 g/g-dried raw material) was generated from dried raw material of M. floridulus after alkaline pretreatment at 90 °C. The acid-catalyzed steam explosion pretreatment also resulted in a high ethanol yield (0.122 g/g-dried raw material). Pretreatment resulting in high lignin and hemicellulose removal rates could make biomass more accessible to enzyme hydrolysis and lead to higher ethanol production.

Organic matter (OM) accounts for a significant fraction of submicron particulate in the atmosphere. The impact of OM on climate and human health is largely contributed by the water-soluble OM (WSOM). Interplay of WSOM and water leads to hygroscopic growth and cloud formation processes. Magnitude of the organic hygroscopicity can be determined by the polarity distribution of WSOM, yet experimental method to systematically examine the relationship is not available. This thesis presents a novel framework to classify WSOM according to its 1-octanol−water partition coefficient (KOW), which often serves as a metric of polarity and water solubility. Fractionization of OM by the KOW approach offers information about the degree of oxidation, which has been viewed as a critical indicator in governing the thermodynamic properties of OM. A theoretical method was developed to classify WSOM by varying the volume ratio of 1-octanol and aqueous phases and extraction steps. An inversion algorithm was further developed to derive KOW distribution of WSOM. The method was verified by OM from proxy of biomass burning particles, and applied to Indonesian biomass burning particles. Optical and chemical characteristics of the extracted WSOM were measured by UV−visible spectrophotometer, spectrofluorometer, and aerosol mass spectrometer. Deconvolution methods including positive matrix factorization, parallel factor analysis, and least-squares analysis were applied to the measured spectra, categorizing WSOM into three classes. The highly polar fraction of WSOM (log KOW < 0) is dominated by highly oxygenated species; the marginally polar fraction (0 ≤ log KOW ≤ 1) likely contains aromatic compounds; while the least polar fraction (log KOW ≥ 1) mostly consists of hydrocarbon-like species. Comparison with hygroscopicity measurements indicates that only WSOM in the highly polar fraction (log KOW < 0) can significantly contribute to water uptake. Doctor of Philosophy

The marine microalgae Nannochloropsis oculata is a promising source of biofuel because of its high lipid content. For achieving high productivity of oil from microalgae, a high cell concentration before harvesting is beneficial. The present study investigated fed-batch cultures of N. oculata fed with vitamins and nutrient solutions and found that the biomass yield of N. oculata in the fed-batch culture was 1.25 times higher than that in batch culture. Fed-batch cultivation, especially at high illumination, decreased the inhibitory effect of high carbon dioxide (CO 2 ) concentration on the microalgal growth. The specific growth rate was directly proportional to the light intensity in the CO 2 environment. A light intensity of 40,000 Lux was able to achieve high specific growth rates in fed-batch cultivation at a CO 2 volume fraction of 2%–15%. The tolerance of N. oculata to CO 2 was enhanced by the daily feeding of nutrients in the fed-batch cultivation. At 2% CO 2 , a final cell density of about OD 682 = 11.4 was achieved in the fed-batch culture in 30 days. Furthermore, a cell density of 14.4 g L −1 was obtained by outdoor fed-batch cultivation in 27 days.

BH2, a monoclonal antibody prepared against the denatured human leukocytic antigen-B27 heavy chain (HLA-B27 HC), can immunoprecipitate the misfolded HLA-B27 HC complexed with Bip in the endoplasmic reticulum and recognize the homodimerized HLA-B27 HC that is often observed on the cell membrane of patients suffered from ankylosing spondylitis (AS). However, the recognition specificity of BH2 toward the other molecules of HLA-B type and toward the different types of HLA molecules remained uncharacterized. In this study, we carried out the HLA-typing by using the Luminex Technology to characterize the recognition specificity of BH2 and analyzed the binding domain of HLA-B27 HC by BH2. Our results indicated that BH2 preferably binds to molecules of HLA-B and -C rather than HLA-A and the binding site is located within the α2 domain of HLA-B27 HC.

This report describes a novel way to generate a highly effective hydrophobic cement surface via a carbonation route using sodium stearate. Carbonation reaction was carried out at different temperatures to investigate the hydrophobicity and morphology of the calcium carbonate formed with this process. With increasing temperatures, the particles changed from irregular shapes to more uniform rod-like structures and then aggregated to form a plate-like formation. The contact angle against water was found to increase with increasing temperature; after 90 °C there was no further increase. The maximum contact angle of 129° was obtained at the temperature of 60 °C. It was also found that carbonation increased the micro hardness of the cement material. The micro hardness was found to be dependent on the morphology of the CaCO3 particles. The rod like structures which caused increased mineral filler produced a material with enhanced strength. The 13C cross polarization magic-angle spinning NMR spectra gave plausible explanation of the interaction of organic-inorganic moieties.

Acetic acid, a potential growth inhibitor, commonly occurs in lignocellulosic hydrolysates. The growth of Cupriavidus necator DSM 545 and production of poly(3-hydroxybutyrate) (PHB) by this bacterium in a glucose-based medium supplemented with various initial concentrations of acetic acid are reported. The bacterium could use both glucose and acetic acid to grow and produce PHB, but acetic acid inhibited growth once its initial concentration exceeded 0.5 g/L. As acetic acid is an unavoidable contaminant in hydrolysates used as sugar sources in commercial fermentations, a mathematical model was developed to describe its impact on growth and the production of PHB. The model was shown to satisfactorily apply to growth and PHB production data obtained in media made with acetic-acid-containing hydrolysates of Napier grass and oil palm trunk as carbon substrates.

The relationship between hygroscopic properties and chemical characteristics of Indonesian biomass burning (BB) particles, which are dominantly generated from peatland fires, was investigated using the humidified tandem differential mobility analyzer. In addition to peat, acacia (a popular species at plantation) and fern (a pioneering species after disturbance by fire) were used for experiments. Fresh Indonesian peat burning particles are almost non-hygroscopic (mean hygroscopicity parameter, κ

The process of separating oil and water from oil/water mixtures is an attractive strategy to answer the menace caused by industrial oil spills and oily wastewater. In addition, water coproduced during hydrocarbon exploitation, which can be an economic burden and risk for freshwater resources, can become an important freshwater source after suitable water-oil separation. For oil-water separation purposes, considerable attention has been paid to the preparation of hydrophobic - oleophilic materials with modified surface roughness. However, due to issues of thermodynamic instability, costly and complex methods as well as lack of ecofriendly compounds, most of hydrophobic surface modified particles are of limited practical application. The study presents a facile procedure, to synthesize crystalline particles of calcite, which is the most stable polymorph of CaCO 3 from industrial CaCO 3 using oleic acid as an additive in a one-pot synthesis method. The XRD results show that the synthesized particles were a well-crystallized form of calcite. The FTIR results reflect the appearance of the alkyl groups from the oleic acid in synthesized particles which promotes the production of calcite with ‘rice shape’ (1.64 μm) (aggregated by spherical nanoparticle of 19.56 nm) morphology with concomitant changes in its surface wettability from hydrophilic to hydrophobic. The synthesized particles exhibited near to super hydrophobicity with ∼99% active ratio and a contact angle of 143.8°. The synthesized hydrophobic calcite particles had an oleophilic nature where waste diesel oil adsorption capacity of synthesized calcium carbonate (HCF) showed a very high (>99%) and fast (7 s) oil removal from oil-water mixture. The functional group of long alkyl chain including of C O bounds may play critical roles for adsorption of diesel oils. Moreover, the thermodynamically stable crystalline polymorph calcite (compared to vaterite) exhibited excellent recyclability. The isothermal study reflects the comparatively high value of correlation coefficient (R 2 = 0.94) for the Langmuir isotherm compared to those of the Freundlich isotherm (R 2 = 0.82) showed that the adsorption of diesel oil onto the hydrophobic CaCO 3 adsorbent was much better described by the Langmuir isotherm. The kinetics study of second-order rate expression (R 2 = 0.99) more fitted with the experimental data compare to first-order model (R 2 = 0.92). The synthesized calcite exhibited a significant dual oleophilic and hydrophobic nature that can be applicable for oil adsorption/or removal purpose in oil contaminated areas in environment and/or industrial oily wastewater for green, simple, and inexpensive environmental cleanup.

A co-expression system was established in Escherichia coli for enhancing the cellular expression of heat shock transcription factor, sigma 32 (σ(32)). A Shine-Dalgarno sequence and the rpoH gene of E. coli, which encodes σ(32), were cloned into a bacterial plasmid containing a gene fusion encoding a doubly tagged N-acetyl-d-neuraminic acid aldolase (GST-Neu5Ac aldolase-5R). After the IPTG induction, a substantially higher level of sigma 32 was observed up to 3 h in the co-expression cells, but an enhancement in the solubility of target protein was manifest only in the first hour. Nevertheless, the co-expression of sigma 32 led to higher level of Neu5Ac aldolase enzymatic activity in both the soluble and insoluble (inclusion body) fractions. The Neu5Ac aldolase activity of the supernatant from the lysate of cells co-expressing GST-Neu5Ac aldolase-5R and recombinant σ(32) was 3.4-fold higher at 3 h postinduction than that in cells overexpressing GST-Neu5Ac aldolase-5R in the absence of recombinantly expressed σ(32). The results of acrylamide quenching indicated that the conformational quality of the fusion protein was improved by the co-expression of recombinant σ(32). Thus, the increased level of intracellular σ(32) might have created favorable conditions for the proper folding of recombinant proteins through the cooperative effects of chaperones/heat shock proteins expressed by the E. coli host, which resulted in smaller inclusion bodies, improved conformational quality and a higher specific activity of the overexpressed GST-Neu5Ac aldolase-5R protein.

Xylitol is an important commercial sweetener that can be produced by fermentation. Previous studies of xylitol production have not been able to combine high average productivity and yield in a single process. Benzoate is a highly chaotropic stressor and has been found to stimulate the fermentation metabolism of yeasts at low concentrations. Therefore, in the current work, it was hypothesized that benzoate increases xylitol production, because it is a concurrent kosmotropic/compatible solute under aerobic conditions. Shake flask experiments without control of dissolved oxygen revealed that sodium benzoate added at a concentration of up to 150 ppm stimulated the fermentation of xylose to xylitol by Candida mogii. Sodium benzoate at a concentration of >200 ppm had a clear inhibitory effect on the xylose metabolism. Controlled batch fermentations carried out in bioreactors with and without sodium benzoate (150 ppm) were used to further assess its potential for improving the xylitol production. Under highly aerobic conditions (dissolved oxygen concentration >75% of air saturation), the presence of sodium benzoate (150 ppm) increased both specific xylitol productivity and yield. The specific xylitol productivity increased by >2-fold and the yield increased by ∼30%, relative to control. However, benzoate increased the xylitol yield only slightly under oxygen limiting conditions. The volumetric xylitol productivity previously obtained for most potential strains was highest under microaerobic conditions. However, in the current study, the xylose consumption was remarkably enhanced under aerobic conditions in the presence of sodium benzoate, which makes an increase in the volumetric productivity of xylitol feasible for industrial applications. This method is readily applicable to previously developed xylitol processes by simply adding a suitable amount of sodium benzoate. The findings of this study devise new interventions for microbial processes in industrial reactors to expand the microbial tolerance of chaotropic stressors and, hence, the biotic windows for such processes.

An experimental method for producing ethanol continuously was designed and tested with a cell-recycling two-tank system, which was composed of two fermentors, each of which was individually equipped with a settler for recycling flocculent yeast. This system was effective for the continuous fermentation of ethanol from sucrose at high cell-recycling ( r = 0.8–0.9) and dilution (up to 0.48 h −1 ) rates. The system has several advantages; the high cell concentration in the fermentors and relief of substrate and product inhibition. Thus, the enhanced productivity using this continuous fermentation with the two-tank cell-recycling system was significantly higher compared with that of the batch fermentation. The results indicate that increased recycling ratios caused an increase in biomass concentration and subsequently, product concentration in the tank. The ethanol productivity increased with the dilution rate, but higher dilution rates could render increasing amounts of sugar unconverted. Continuous fermentation with the sugar feed concentration of 160 g/l at r = 0.9 and dilution rate of 0.2 h −1 achieved the highest productivity with less than 2% of the unconverted sugar in the product steam. Under the same cell recycling ratios a productivity range of 6.9–7.5 g/l h −1 could be achieved with feeding concentrations of 80–200 g/l, while batch fermentation at these sugar concentrations led to productivities of 3.85–4.48 g/l h −1 .

The production of ethanol from sugarcane bagasse by simultaneous saccharification and fermentation (SSF) using thermotolerant Kluveromyces marxianus var. marxianus and commercial cellulase of Accellerase 1000 was investigated. Sugarcane bagasse pretreated with NaOH at the room temperature for 24 h resulted in an increase in cellulose content to 55.2% (w/w). With 10% of water-insoluble-solids (WIS) at pH 5.0 supplemented with 0.2 ml cellulase/g-WIS and 1 g/L of thermotolerant yeast, the SSF of pretreated sugarcane bagasse conducted in flasks led to a respective theoretical ethanol yield of 85.1%, 92.2% and 76.2% under 37, 42 and 45 °C. As the rotary drum reactor was scaled up to 100L and loaded with 10 kg alkali-pretreated sugarcane bagasse, the SSF at 42 °C for 72 h along with same doses of WIS, cellulase and yeast resulted in a final ethanol concentration and the theoretical ethanol yield of 24.6 g/L and 79%, respectively. These observations indicated that the performance and the chosen SSF operating conditions for the scale-up drum reactor was as effective as those attained from flask runs. As demonstrated, the use of rotary drum reactor for cellulosic ethanol production under SSF operating conditions is simple to scale up and shows commercial potential.

Endo-xylanase secreted by the alkaliphilic Bacillus halodurans was immobilized onto an anionic exchange resin via the ionic linkage and the highest immobilized amount was achieved at pH 8. Approximately 0.4 mg of enzyme could be coupled onto 1 g of anionic exchanger. Time courses of the xylooligosaccharides (XOS) produced from corncob xylan indicated that the immobilized enzyme tends to use shorter xylan chains as the substrate and to produce more xylobiose and xylotriose initially. On the contrary, when free enzyme was employed, products at initial stage of the reaction exhibited higher level of oligomers with degree of polymerization greater than 4, suggesting that free xylanase worked on both longer (insoluble) and shorter (soluble) xylan chains. At the end of 24 h reaction, XOS mixture contained a total of 25.2% and 32.5% (w/w) of xylobiose and xylotriose with immobilized xylanase and free xylanase, respectively. The conversions for converting substrate xylan to soluble XOS with immobilized xylanase was determined to be 80.9%, which was lower than the use of free xylanase (99.8%). The combination of free and immobilized xylanase can be employed to further improve the conversion of XOS.

A method for fast delivery of proteins conjugated to superparamagnetic iron oxide nanoparticles (SPION) into mammalian cells by applying a strong magnetic field in pulses was proposed. Firstly, SPION were prepared from an alkaline solution of divalent and trivalent iron ions and covalently bound with protein through the activation of N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC). After fluorescently labelling, the protein-nanoparticle conjugate was mixed with mammalian cell line and exposed to a pulsed magnetic field for short durations of few milliseconds. Results suggested that superparamagnetic nanoparticles were able to carry proteins into living cells immediately. Cellular internalization of the fluorescently labelled protein-nanoparticle conjugate was proved by the observation of cell fluorescence in a fluorescent microscopy, as well as cell analysis by a flow cytometer. We found that the cellular uptake was accomplished dominantly by the process of bombardment of magnetic nanoparticles.

To investigate potential implications of microbial activity on sand bioconsolidation and subsurface environments, two ureolytic strains, Sporosarcina pasteurii and Bacillus subtilis were tested for the production of calcium carbonate (CaCO3). Laboratory experiments with monoculture S. pasteurii (column 1) and coculture S. pasteurii-B. subtilis (column 2) were conducted to determine urea and calcium chloride reactivity and volumetric carbonate formation. Both columns were able to consolidate sand, whereas, column 1 induced greater CaCO3 precipitation. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed two columns with different mineralogy with calcite, and vaterite formation. Column 1 showed rhombohedral and trigonal crystals morphology, whereas column 2 developed the prismatic calcite and the spherulite vaterite crystals might be due to the differences of the micro-environment caused by the urease expression of these bacterial species. These results indicate the possibility of using those crystals to cement loose sand whereas, highlighted the importance of combining these techniques to understand the geomicrobiology found in the subsurface environments.

Chronic circadian desynchronization induced by repeated 12 h light-dark cycle shifts conducted twice weekly resulted in elevated food intake, body weight gain, and retroperitoneal fat mass in male F344 rats. Using a proteomic approach, we found that repeated light-dark shifts caused changes in expression levels of five hypothalamic (four upregulated) and 22 retroperitoneal fat (13 upregulated) 2-DE protein spots. Proteins involved in carbohydrate metabolism and in the citric acid cycle were upregulated, indicating a positive energy balance status. In addition, the hypothalamic gamma-amino butyric acid (GABA) aminotransferase was upregulated, thus suggesting a connection between the brain GABAeric system and the modulation of food intake. Furthermore, the upregulation of fatty acid-binding protein 4 and the downregulation of 78 kDa glucose-regulated protein in the fat implicated the development of insulin resistance. We observed the upregulation of two antioxidant enzymes that might serve as protection against insulin dysfunction associated with oxidative stress. Finally, the downregulation of hypothalamic voltage-dependent anion-selective channel protein 1 and fat ATP synthase suggested a reduction in synthesis of mitochondrial ATP. These findings are in partial agreement with those of studies of obesity induced by genotype and a high-fat diet.

A novel formulation method was suggested to prepare rumen-protected amino acid by coating chitosan on the particles of hydrogenated fat entrapping amino acid. Chitosan coating that was formed due to the coacervation either by the addition of ethanol or sodium hydroxide to the acetic acid solution of chitosan could increase the retention of amino acid in the fat prills. Both protected methionine and arginine particles showed a sustained release behavior in simulated rumen conditions. In the pH 5.5 buffer, the protected arginine particles coated with chitosan by the coacervation using NaOH could retain about 80% of arginine. When the coacervation with the addition of ethanol was employed, the chitosan-coated particles could retain even 97% of arginine. The chitosan-coated methionine particles prepared by addition of ethanol led to almost the same level (85%) of retention as the commercial product Mepron M85. Both the Higuchi kinetics and the model for the release of agent dissolved in polymer matrix could well describe the control release of protected amino acid.

Folic acid (FA) was coupled onto titanium dioxide nanoparticles to provide a specificity of cell targeting. Modification was confirmed by infrared absorption spectra and zeta potential that suggested a formation of linkage between carboxylic acid of FA and titanium dioxide. The surface attachment of folic acid did not cause a significantly change in particles size, but led to a reduction of photocatalytic activity of TiO 2 . The FA-modified TiO 2 nanoparticles could be internalized by cells at a much faster rate than the unmodified TiO 2 , due to the mediation of folate receptor on the cancer cells. The UV irradiation caused death of HeLa cells pretreated with FA-modified TiO 2 more effectively than that of HeLa cells treated with unmodified TiO 2 . Results suggest that to modify TiO 2 with folic acid using appropriately the FA-to-TiO 2 mass ratio of 0.2 could yield nanoparticles having higher cytotoxicity under photoexcitation. Photocatalytic TiO 2 nanoparticles could not only damage to cellular components including plasma membranes leading to cell nucrosis but also induce the programming cell death. Results from flow cytometry-based analysis indicated that the mechanism of cell death was a combination of necrosis and apoptosis.

Surface-functionalized magnetic poly(styrene–glycidyl methacrylate) (PS–GMA) microspheres were prepared and coupled with Sca-1 antibody for cell selection from murine bone marrow mononuclear cells (MNCs). Biotinylated Sca-1 antibody could be directly coupled to avidin-bound magnetic microspheres. Alternatively, oxidized goat anti-mouse antibody was covalently bound onto the amino group-containing magnetic microspheres in a site-directed manner, and the resultant conjugate was coupled with non-modified Sca-1 antibody. Using the indirect antibody-bound magnetic microspheres, the purity of isolated Sca-1+ cells increased with bead-to-cell ratio. Using a bead-to-cell ratio of 10 beads/cell, a purity of 85% Sca-1+ cells corresponding to a 17-fold enrichment was achieved.

Through the use of superparamagnetic iron oxide nanoparticles (SPIONs), fast delivery of DNA into adherent and suspended cells could be achieved by the mediation of a strong impulsed magnetic field. Mammalian cells were well transfected with enhanced green fluorescent protein gene. To mediate the cellular uptake, cells and nucleic acid complexes were mixed together and exposed once or several times to impulsed magnetic field for short durations of few milliseconds. In the transfection of adherent cells, most complexes of plasmid DNA and polyethylenimine (PEI)-coated SPIONs were internalized immediately. In comparison with no magnetic pulsing, the enhancement in transfection efficiency was about two fold on average by pulsing in magnetic field of 0.6 Tesla three times. The transfection yield increased with the strength of magnetic field and the number of pulsing. Disregarding the cytotocixity of internalized PEI, the loss of cell viability by magnetic pulsing was not evidenced.

Two SDS-resistant endochitinases, designated as ASCHI53 and ASCHI61, were isolated from Aeromonas schubertii in a soil sample from southern Taiwan. MALDI-TOF mass measurement indicates the molecular weights of 53,527 for ASCHI53 and 61,202 for ASCHI61. N-terminal and internal amino acid sequences were obtained, and BLAST analysis of the sequences and MS/MS peptide sequencing showed that they were novel proteins. Degradation of chitin by these two endochitinases gave rise to hexameric chitin oligosaccharide, a compound known to have several potent biomedical functions. ASCHI53 and ASCHI61 retained, respectively, 65% and 75%, of their chitinase activity in the presence of 5% SDS and 100% of their activity in the presence of 10% β-mercaptoethanol. These results demonstrate that they are SDS-resistant endochitinases and probably have a rigid structure. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009

A swelling and penetration process is proposed to prepare magnetic polymer microspheres. Micron-size polystyrene (PS) particles were swollen in an aqueous solution of N-methyl-2-pyrrolidone (NMP) and then mixed with superparamagnetic iron oxide nanoparticles. The magnetic nanoparticles were able to diffuse into polymer microspheres and were entrapped within the polymer microspheres. The saturation magnetization of resultant magnetic polymer microspheres increased as increasing magnetic nanoparticle concentrations were added to the swelling mixture. A higher ratio of NMP-to-water led to a greater swelling but a larger loss of polymer mass due to polymer chain dissolution in the NMP solution. Sodium dodecyl sulfate (SDS) in the NMP aqueous solution significantly enhanced the swelling and penetration process. The use of SDS could not only shorten the process time but also lower the required NMP concentration. The proposed method also worked well in preparing magnetic polymers microspheres with other styrene-based copolymer beads like poly(styrene–glycidyl methacrylate) (PS–GMA).

Rice straw after pretreatment was used as the substrate to induce the production of cellulases by a cellulase-producing strain Trichoderma reesei Rut C-30. Compared with concentrated KH 2 PO 4 medium, the medium with low concentration of KH 2 PO 4 could yield higher enzymatic activities for cellulose hydrolysis. The use of alkaline-treated rice straw sticks and non-pretreated rice straw powder as the inducing substrates in batch culture could result in cellulase activities of 1.07 and 0.71 FPU/ml, respectively. These levels are comparable to values reported in the literature on the use of other cellulose sources as the inducers. Results from two-dimensional gel electrophoresis (2-DE) of proteins secreted by the T. reesei strain using trichloroacetic acid (TCA) precipitation were reproducible. Among cellulase components, cellobiohydrolases (CBH) were found to dominate over about 37% of the total extracellular proteins, according to 2-DE gel. The enzymatic activity could be correlated with the protein expression level determined based on the image intensity on the 2-DE gel.

A novel method for the preparation of polymer-based, magnetic microspheres is proposed. Pre-made, poly(styrene-glycidyl methacrylate) (PS-GMA) particles of micron size were swollen by a mixture of N-methyl-2-pyrrolidone and water, and then incubated with superparamagnetic nanoparticles. The nanoparticles were allowed to diffuse into polymer microspheres during the incubation, became entrapped and made the polymer microspheres superparamagnetic. These magnetic PS-GMA microspheres were chemically modified and then coupled with single-stranded oligonucleotides as probes for DNA hybridization. The immobilized probes showed repeatable capture of target oligonucleotides.