Preparation and Characteristics of Polyethylene Oxide/Curdlan Nanofiber Films by Electrospinning for Biomedical Applications.

In this study, polyethylene oxide (PEO) and curdlan solutions were used to prepare PEO/curdlan nanofiber films by electrospinning using deionized water as the solvent. In the electrospinning process, PEO was used as the base material, and its concentration was fixed at 6.0 wt.%. Moreover, the concentration of curdlan gum varied from 1.0 to 5.0 wt.%. For the electrospinning conditions, various operating voltages (12-24 kV), working distances (12-20 cm) and feeding rates of polymer solution (5-50 µL/min) were also modified. Based on the experimental results, the optimum concentration for the curdlan gum was 2.0 wt.%. Additionally, the most suitable operating voltage, working distance and feeding rate for the electrospinning process were 19 kV, 20 cm and 9 µL/min, respectively, which can help to prepare relatively thinner PEO/curdlan nanofibers with higher mesh porosity and without the formation of beaded nanofibers. Finally, the PEO/curdlan nanofiber instant films containing 5.0 wt.% quercetin inclusion complex were used to perform wetting and disintegration processes. It was found that the instant film can be dissolved significantly on the low-moisture wet wipe. On the other hand, when the instant film touched water, it can be disintegrated very quickly within 5 s, and the quercetin inclusion complex was dissolved in water efficiently. Furthermore, when the instant film encountered the water vapor at 50 °C, it almost completely disintegrated after immersion for 30 min. The results indicate that the electrospun PEO/curdlan nanofiber film is highly feasible for biomedical applications consisting of instant masks and quick-release wound dressings, even in the water vapor environment.

The Anti-inflammatory Effects of the Bioactive Compounds Isolated from Alpinia officinarum Hance Mediated by the Suppression of NF-kappaB and MAPK Signaling.

This study was designed to evaluate the anti-inflammatory effects of Alpinia officinarum Hance extract (AOE) and identify its main active ingredients. AOE was obtained using a 95% ethanol extraction method. Lipopolysaccharide (LPS) were used to induce an inflammatory response in RAW264.7 cells. The results showed that AOE exerts anti-inflammatory effects via inhibition of prostaglandin E2 secretion and cyclooxygenase -2 (COX-2) production. We further analyzed the components of AOE using high-performance liquid chromatography and found that AOE is comprised of several bioactive flavonoids including quercetin (Q), kaempferol (K), galangin (G), and curcumin (C). These four flavonoids effectively inhibited nitric oxide (NO), interleukin (IL)-1ß, IL-6, and tumor necrosis factor-α production. Moreover, they reduced COX-2 and inducible NO synthase expressions via regulation of nuclear factor kappa-light-chain-enhancer of activated B cells and c-Jun N-terminal kinase signaling pathways. Furthermore, we compared and contrasted the anti-inflammatory effects and mechanisms of these four flavonoids at the same dose in the LPS-induced cell inflammation model. The results showed that C is the most effective inhibitor of LPS-induced NO production. However, only Q and K effectively attenuated LPS-induced extracellular signal-regulated kinase and p38 elevations. In conclusion, AOE and its major bioactive compounds exert anti-inflammatory effects on LPS-induced inflammation. As A. officinarum Hance is much cheaper than any of its four flavonoids, especially G, we suggest using AOE as an anti-inflammatory agent.

Simultaneous study of antioxidant activity, DNA protection and anti-inflammatory effect of Vernonia amygdalina leaves extracts.

Vernonia amygdalina (VA) has been reported to have antioxidant potential; however, its DNA protection and anti-inflammatory properties remain unclear. We aimed to investigate whether aqueous (WEVAL) and alcoholic (EEVAL) VA extracts exert similar antioxidant, DNA protection and anti-inflammatory effects and attempted to explore the mechanism underlying the anti-inflammatory effects. These results demonstrated that WEVAL had greater polyphenolic and flavonoid contents, as well as a stronger reducing power, DPPH radical scavenging and DNA protective activity. Moreover, both extracts reduced lipopolysaccharide (LPS)-induced expression of COX-II, iNOS, pro-inflammatory factors, including NO, TNF-α, IL-1ß, and IL-10. Compared with WEVAL, EEVAL was a more potent inflammatory inhibitor. Both extracts similarly inhibited LPS-induced MAPK (p38) and NF-κB expression. Our findings indicate that WEVAL and EEVAL have diverse antioxidant and anti-inflammatory effects. WEVAL had a stronger antioxidant and DNA protection activity; contrastingly, EEVAL had a stronger anti-inflammatory ability. The anti-inflammatory activity involves reduced pro-inflammatory cytokines through NF-κB down-regulation and MAPK inhibition. These results demonstrated that production of WEVAL and EEVAL from VA leaves may provide a safe and efficacious source of pharmaceutical applications, with antioxidant, DNA protective and anti-inflammation activities.

A New Natural Antioxidant Biomaterial from Cinnamomum osmophloeum Kanehira Leaves Represses Melanogenesis and Protects against DNA Damage.

Cinnamomoum osmophloeum Kanehira (COK) is an indigenous tree species in Taiwan. Chemical compositions, antioxidant activity, mushroom tyrosinase inhibition, melanin synthesis repression, and protection against DNA damage of hydrosol from the COK leaves by steam distillation were examined. We performed 1,1-diphenyl-2-picrylhydrazyl radical scavenging, metal ion chelating, reducing power, and Trolox equivalent antioxidant capacity (TEAC) assays and determined the correlations between total phenolic contents and antioxidant activities. The findings showed that the anti-oxidative properties of COK hydrosol are closely correlated with their phenol contents. Additionally, the major constituents of hydrosol, i.e., cinnamaldehyde and benzaldehyde, had dose-dependent anti-tyrosinase effects against both monophenolase and diphenolase activities. GC-MS analysis revealed that the major bioactive components of hydrosol were trans-cinnamaldehyde (87.7%), benzaldehyde (7.0%), and cinnamyl acetate (5.3%). Moreover, we found that the hydrosol with the presence of benzaldehyde is more potent than pure cinnamaldehyde, and enhances the tyrosinase inhibitory activity of hydrosol. In kinetic analyses, Lineweaver-Burk plots and replots showed that COK hydrosol is a mixed-type inhibitor. Additionally, we found that very low doses of COK hydrosol repressed α-melanocyte-stimulating hormone-induced synthesis of microphthalmia-associated transcription factor, leading to decreased melanin synthesis in B16-F10 melanoma cells. These results demonstrated that production of hydrosol from COK leaves using steam distillation may provide a safe and efficacious source of skin-whitening agents for cosmetic and pharmaceutical applications, with antioxidant, anti-tyrosinase, anti-melanogenesis, and DNA protective activities.

Effect of carbon sources on growth and lipid accumulation of newly isolated microalgae cultured under mixotrophic condition.

In order to produce microalgal lipids that can be transformed to biodiesel fuel, one isolate with high lipid content was identified as Chlorella sp. Y8-1. The growth and lipid productivity of an isolated microalga Chlorella sp. Y8-1 were investigated under different cultivation conditions, including autotrophic growth (CO2, with light), heterotrophic growth (sucrose, without light) and mixotrophic growth (organic carbon sources and CO2, with light). Mixotrophic Chlorella sp. Y8-1 showed higher lipid content (35.5±4.2%) and higher lipid productivity (0.01 g/L/d) than Chlorella sp. Y8-1 cultivated under autotrophic and heterotrophic conditions on modified Walne medium. Fatty acid analysis of Chlorella sp. Y8-1 showed the major presence of palmitic acid (C16:0), oleic acid (C18:1), linoleic acid (C18:2) and linolenic acids (C18:3). The main fatty acid compositions of the Chlorella sp. Y8-1 are appropriate for biodiesel production.

Sequential acid and enzymatic hydrolysis in situ and bioethanol production from Gracilaria biomass.

Gracilaria sp., a red alga, was used as a feedstock for the production of bioethanol. Saccharification of Gracilaria sp. by sequential acid and enzyme hydrolysis in situ produced a high quality hydrolysate that ensured its fermentability to produce ethanol. The optimal saccharification process resulted in total 11.85g/L (59.26%) of glucose and galactose, Saccharomyces cerevisiae Wu-Y2 showed a good performance on co-fermentability of glucose and galactose released in the hydrolysate from Gracilaria sp. The final ethanol concentrations of 4.72g/L (0.48g/g sugar consumed; 94% conversion efficiency) and the ethanol productivity 4.93g/L/d were achieved. 1g of dry Gracilaria can be converted to 0.236g (23.6%) of bioethanol via the processes developed. Efficient alcohol production by immobilized S. cerevisiae Wu-Y2 in batch and repeated batch fermentation was also demonstrated. The findings of this study revealed that Gracilaria sp. can be a potential feedstock in biorefinery for ethanol production.

Fast incorporation of primary amine group into polylactide surface for improving C2C12 cell proliferation using nitrogen-based atmospheric-pressure plasma jets.

In this article, we report the development of the fast incorporation of primary amine functional groups into a polylactide (PLA) surface using the post-discharge jet region of an atmospheric-pressure nitrogen-based dielectric barrier discharge (DBD). Plasma treatments were carried out in two sequential steps: (1) nitrogen with 0.1% oxygen addition, and (2) nitrogen with 5% ammonia addition. The analyses show that the concentration of N/C ratio, surface energy, contact angle, and surface roughness of the treated PLA surface can reach 19.1%, 70.5 mJ/m(2), 38° and 73.22 nm, respectively. In addition, the proposed two-step plasma treatment procedure can produce a PLA surface exhibiting almost the same C2C12 cell attachment and proliferation performance as that of the conventional gelatin coating method. Most importantly, the processing/preparation time is reduced from 13-15 h (gelatin coating method) to 5-15 min (two-step plasma treatment), which is very useful in practical applications.

Production of keratinolytic enzyme by an indigenous feather-degrading strain Bacillus cereus Wu2.

A novel feather-degrading microorganism was isolated from a poultry farm in Taiwan, and was identified Bacillus cereus Wu2 according to 16S rRNA sequencing. The isolated strain produces keratinolytic enzyme using chicken feather as the sole carbon and nitrogen source. The experimental results indicated that the extra carbon sources (glucose, fructose, starch, sucrose, or lactose) could act as a catabolite repressor to the enzyme secretion or keratinolytic activity when keratinous substrates were employed as protein sources. However, addition of 2 g/L of NH(4)Cl to the feather medium increased the enzyme production. The optimum temperature and initial pH for enzyme production were 30°C and 7.0, respectively. The maximum yield of the enzyme was 1.75 kU/mL in the optimal chicken feather medium; this value was about 17-fold higher than the yield in the basal hair medium. The B. cereus Wu2 possessed disulfide reductase activity along with keratinolytic activity. The amino acid contents of feathers degradated by B. cereus Wu2 were higher, especially for lysine, methionine and threonine which were nutritionally essential amino acids and usually deficient in the feather meal. Thus, B. cereus Wu2 could be not only used to enhance the nutritional value of feather meal but is also a potential bioinoculant in agricultural environments.

Cadmium biosorption by polyvinyl alcohol immobilized recombinant Escherichia coli.

Recombinant Escherichia coli expressing human metallothionein protein was immobilized with polyvinyl alcohol (PVA) for the removal of cadmium from solution. The adsorption ability was strongly affected by pH with optimal performance at pH 5.0, while it was less sensitive to temperature over the range of 20-42 degrees C. The adsorption kinetics and equilibrium of PVA-immobilized cells was best described by pseudo-second order model and Langmuir isotherm, respectively. Over the Cd concentrations range of 10-150 mg/l, PVA-cells had the highest Cd removal percentage (82.7%) at 10mg Cd/l and a biomass loading of 15.4 wt.%. Better adsorption ability was obtained when biomass loading was increased, as the highest adsorption capacity of 4.29 mg/g was achieved at 33.0 wt.% of biomass (initial Cd concentration=100mg/l). An aqueous solution of 0.01 M Na(3)NTA displayed the best desorption efficiency (57-89%) for four A/D cycles, while 51-61% of the original adsorption capacity was retained after regeneration.

Adsorption of direct dyes from aqueous solutions by carbon nanotubes: determination of equilibrium, kinetics and thermodynamics parameters.

This study examined the feasibility of removing direct dyes C.I. Direct Yellow 86 (DY86) and C.I. Direct Red 224 (DR224) from aqueous solutions using carbon nanotubes (CNTs). The effects of dye concentration, CNT dosage, ionic strength and temperature on adsorption of direct dyes by CNTs were also evaluated. Pseudo second-order, intraparticle diffusion and Bangham models were adopted to evaluate experimental data and thereby elucidate the kinetic adsorption process. Additionally, this study used the Langmuir, Freundlich, Dubinin and Radushkevich (D-R) and Temkin isotherms to describe equilibrium adsorption. The adsorption percentage of direct dyes increased as CNTs dosage, NaCl addition and temperature increased. Conversely, the adsorption percentage of direct dyes decreased as dye concentration increased. The pseudo second-order model best represented adsorption kinetics. Based on the regressions of intraparticle diffusion and Bangham models, experimental data suggest that the adsorption of direct dyes onto CNTs involved intraparticle diffusion, but that was not the only rate-controlling step. The equilibrium adsorption of DR86 is best fitted in the Freundlich isotherm and that of DR224 was best fitted in the D-R isotherm. The capacity of CNTs to adsorb DY86 and DR224 was 56.2 and 61.3 mg/g, respectively. For DY86, enthalpy (DeltaH(0)) and entropy (DeltaS(0)) were 13.69 kJ/mol and 139.51 J/mol K, respectively, and those for DR224 were 24.29 kJ/mol and 172.06 J/mol K, respectively. The values of DeltaH(0), DeltaG(0) and E all indicate that the adsorption of direct dyes onto CNTs was a physisorption process.

Diffusion characteristics and controlled release of bacterial fertilizers from modified calcium alginate capsules.

An indigenous Cellulosimicrobium cellulans GS6 isolate able to solubilize insoluble phosphate complexes in soil is a potential bacterial fertilizer. Enclosure of the phosphate-solubilizing bacterium (PSB) in biodegradable capsules may protect the PSB cells inoculated into soil and, in the meantime, enable the control of cell release that confers long-term fertilizing effects. In this study, calcium alginate (CA) was used as the core matrix to encapsulate cells of C. cellulans GS6. The cell-liberating properties of the CA-based capsules were modified by blending with a variety of supplemental materials (SM), including chitin, cellulose, olive oil, and gelatin. The experimental results showed that the maximum cell-release percentage (MCR%) of the capsules decreased in the order of CA-cellulose>CA-olive oil>CA-chitin>CA-gelatin>CA. Furthermore, a mass transport model was developed to accurately describe the kinetics of cell release results for each capsule. The diffusion coefficient (D(e)) of each capsule was also determined from the model simulation. We found that the estimated D(e) values are positively correlated to the release rate with rare exceptions. Lastly, as our results underscored the crucial roles that the type of capsules plays in the rate and amount of cell release, controlled release of the bacterial fertilizer (C. cellulans GS6 cells) may be achieved via the design of capsule materials.

Rhamnolipid production with indigenous Pseudomonas aeruginosa EM1 isolated from oil-contaminated site.

Rhamnolipid is one of the most effective and commonly used biosurfactant with wide industrial applications. Systematic strategies were applied to improve rhamnolipid (RL) production with a newly isolated indigenous strain Pseudomonas aeruginosa EM1 originating from an oil-contaminated site located in southern Taiwan. Seven carbon substrates and four nitrogen sources were examined for their effects on RL production. In addition, the effect of carbon to nitrogen (C/N) ratio on RL production was also studied. Single-factor experiments show that the most favorable carbon sources for RL production were glucose and glycerol (both at 40 g/L), giving a RL yield of 7.5 and 4.9 g/L, respectively. Meanwhile, sodium nitrate appeared to be the preferable nitrogen source, resulting in a RL production of 8.6g/L. Using NaNO(3) as the nitrogen source, an optimal C/N ratio of 26 and 52 was obtained for glucose- and glycerol-based culture, respectively. To further optimize the composition of fermentation medium, twenty experiments were designed by response surface methodology (RSM) to explore the favorable concentration of three critical components in the medium (i.e., glucose, glycerol, and NaNO(3)). The RSM analysis gave an optimal concentration of 30.5, 18.1, and 4.9 g/L for glucose, glycerol, and NaNO(3), respectively, predicting a maximum RL yield of 12.6 g/L, which is 47% higher than the best yield (8.6 g/L) obtained from preliminary selection tests and single factor experiments (glucose and NaNO(3) as the carbon and nitrogen source). The NMR and mass spectrometry analysis show that the purified RL product contained L-rhamnosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate (RL1) and L-rhamnosyl L-rhamnosyl-beta-hydroxydecanoyl-beta-hydroxydecanoate (RL2). Meanwhile, HPLC analysis indicates that the molar ratio of RL1 and RL2 in the purified rhamnolipid product was ca. 1:1.

Study of mycelial growth and bioactive polysaccharide production in batch and fed-batch culture of Grifola frondosa.

The fermentation of Grifola frondosa was investigated in the shake flasks and a 5-L jar fermenter in batch and fed-batch modes. In the shake-flask experiments, the preferable mycelial growth and exopolysaccharide (EPS) production was observed at relatively low pH; maltose and glucose were preferred carbon sources for high mycelial production. The EPS was doubled after 13 d of cultivation when glucose was increased from 2% to 4%. Yeast extract (YE) (0.4%) in combination with corn steep powder (CSP) (0.6%) and YE (0.8%) in combination with CSP (1.2%) were preferred nitrogen sources for high mycelial production and EPS production, respectively. All plant oils tested significantly stimulate cell growth of G. frondosa but they failed to enhance EPS production. The EPS products usually consisted of two fractions of different molecular sizes varied by the plant oils used. The fed-batch fermentation by glucose feeding was performed when the glucose concentration in the medium was lower than 0.5% (5g/L), which greatly enhanced the accumulation of mycelial biomass and EPS; the mycelial biomass and EPS were 3.97g/L and 1.04g/L before glucose feeding, which reached 8.23g/L and 3.88g/L at 13 d of cultivation. In contrast, the mycelial biomass and EPS in the batch fermentation were 6.7g/L and 3.3g/L at 13 d of cultivation.

Using redox potential to detect microbial activities during clavulanic acid biosynthesis in Streptomyces clavuligerus.

Production of clavulanic acid (CA) by Streptomyces clavuligerus in a shake-flask culture increased from 92 to 180 mg l(-1) with an increased O2 transfer efficiency (0.039 --> 0.058 s(-1)), which maintained the redox potential values above -250 mV. Compared with traditional measures, such as dissolved O2 concentration and respiratory activity, the redox potential can easily be determined and correlates closely with CA production. It can therefore be used to monitor microbial activities during biosyntheses of secondary metabolites.

Evaluation of effective diffusion coefficient and intrinsic kinetic parameters on azo dye biodegradation using PVA-immobilized cell beads.

An immobilized mixed culture (Aeromonas hydrophila, Comamonas testosteroni, and Acinetobacter baumannii) was prepared by entrapment into phosphorylated polyvinyl alcohol (PVA) gel beads. The unsteady-state diffusion mechanism in a gel bead was applied to estimate the effective diffusion coefficients (D(e)) and the partition coefficients (K(p)) of azo dye. In addition, a simple method was developed to determine the intrinsic kinetic parameters of immobilized cells from observed reaction rates and the intrinsic kinetic parameters were then verified by fitting the experimental data into the reaction-diffusion model in a batch reactor running at a well-stirred state. The calculated effectiveness factor (eta(cal)) approached unity at Thiele modulus (Phi) < 0.3 (i.e., d(p) < 0.475 mm). The experimental effectiveness factor (eta(exp)) was in the range of 0.71-0.45 for a corresponding sphere diameter (d(p)) of 1.91 +/- 0.16 to 4.43 +/- 0.07 mm at an initial dye concentration of 200 mg/L. The results show that intraparticle diffusion resistance has a significant effect on the azo dye biodegradation rate.

Hydrodynamic characteristics of immobilized cell beads in a liquid-solid fluidized-bed bioreactor.

This study examined the hydrodynamic characteristics of a liquid-solid fluidized-bed bioreactor using elastic particles (PVA gel beads) of various diameters as carriers. The drag coefficient-Reynolds number, velocity-voidage, and expansion index-Reynolds number relationships observed during fluidization of PVA gel beads in a fluidized bed in our experiments were compared with the published results. Predictions made from previous correlations were examined with our new experimental findings, revealing the inadequacy of most of these correlations. Thus, new correlations describing the above-mentioned relationships are suggested. The drag coefficient of immobilized cell beads is larger than that of free cell ones at the same Reynolds number because the surface of the immobilized cell beads is rougher. For multiparticle systems, the correction factor, f(epsilon), is a function of the falling gel bead properties (Reynolds number) as well as the fluidized gel bead properties (Archimedes number), and depend strongly on the bed voidage (epsilon). A new simple relation was developed to predict easily the epsilon value from 0.5-0.9 at 4,986 < A(r) < 40,745 or 34 < Re(t) < 186. For all the immobilized cell beads used in this study, the prediction error of the bed voidage was less than 5% at epsilon > 0.5. The prediction equations in this study can be further applied to analyzing the hydrodynamic characteristics of a fluidized-bed reactor using similar entrapped elastic particles as carriers.

Decolorization of azo dye using PVA-immobilized microorganisms.

A microbial consortium having a high capacity for rapid decolorization of azo dye (RED RBN) was immobilized by a phosphorylated polyvinyl alcohol (PVA) gel. The immobilized-cell beads exhibited a color removal capability of 75%, even at a high concentration of RED RBN (500 mg l(-1)) within 12 h using flask culture. The continuous operation was conducted at a hydraulic retention time (HRT) of 5-20 h in which the dye loading rate ranged from 240 to 60 mg dye h(-1). A removal efficiency exceeding 90% was obtained at the HRT higher than 10 h. No recognizable destruction of bead appearance was observed in the 6-month operation. Examination of the mechanism of the decolorization process by cell beads indicated that it proceeded primarily by biological decolorization associated with partial adsorption of the dye onto the entrapped cells and gel matrix. Microscopic observation revealed that the microbial consortium contained in the gel beads was at least made up of three kinds of bacterial species. From the economical viewpoint, alternative cheaper nitrogen sources such as fish meal, soybean meal, pharmamedia and vita yeast powder were examined.

Decolorization of the textile dyes by newly isolated bacterial strains.

Six bacterial strains with the capability of degrading textile dyes were isolated from sludge samples and mud lakes. Aeromonas hydrophila was selected and identified because it exhibited the greatest color removal from various dyes. Although A. hydrophila displayed good growth in aerobic or agitation culture (AGI culture), color removal was the best in anoxic or anaerobic culture (ANA culture). For color removal, the most suitable pH and temperature were pH 5.5-10.0 and 20-35 degrees C under anoxic culture (ANO culture). More than 90% of RED RBN was reduced in color within 8 days at a dye concentration of 3,000 mg l(-1). This strain could also decolorize the media containing a mixture of dyes within 2 days of incubation. Nitrogen sources such as yeast extract or peptone could enhance strongly the decolorization efficiency. In contrast to a nitrogen source, glucose inhibited decolorization activity because the consumed glucose was converted to organic acids that might decrease the pH of the culture medium, thus inhibiting the cell growth and decolorization activity. Decolorization appeared to proceed primarily by biological degradation.