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Atmospheric pressure nitrogen-based dielectric barrier discharge (DBD) jet with two-step plasma treatment procedure has been verified to be very effective in facilitating nitrogen-containing group incorporation on Polylactide (PLA) surface. It includes: 1) pretreatment plasma treatment by a nitrogen discharge with a trace amount of oxygen, and 2) ammonia plasma treatment by a nitrogen discharge with a small amount of ammonia. In this study, the optimized operation condition of two-step plasma procedure is investigated under different concentrations of added gases (0-1% oxygen; 0-10% ammonia). XPS analysis shows that ∼0.19 of N/C ratio can be achieved by means of the optimized two-step plasma procedures. Furthermore, a surface amination mechanism is proposed based on the observations of Optical Emission Spectra (OES), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectra (XPS) analyses. [ABSTRACT FROM AUTHOR]

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 (CO 2 , with light), heterotrophic growth (sucrose, without light) and mixotrophic growth (organic carbon sources and CO 2 , 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. [ABSTRACT FROM AUTHOR]

Highlights: [•] Red seaweed Gracilaria sp. was used as a feedstock for bioethanol production. [•] Sequential acid and enzyme hydrolysis in situ resulted in a high quality hydrolysate. [•] Ethanol production using hydrolysate of Gracilaria was by free and immobilized yeast. [•] Ethanol yield obtained was 0.48g/g sugar consumed accounting for 94% efficiency. [•] 1g of dry Gracilaria was converted to 0.236g of ethanol via the developed processes. [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate that, by adding a small amount of \CF4 (2\%) into a compressed-air planar dielectric barrier discharge (DBD), one can effectively inactivate a B. subtilis spore up to 50 mm in width in the postdischarge jet region after ten passes of exposure of plasma plume (equivalent plasma exposure time of 1 s) for treatment distance of up to 14 mm for the spore concentration in the range of 10^5-10^7 CFU/mL. A possible mechanism is proposed, i.e., the chemically active F atoms and \CFn\ ({n} = 1 - 3) are generated through the help of abundant excited nitrogen molecules in the postdischarge region. [ABSTRACT FROM PUBLISHER]

Abstract: 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°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 10–150mg/l, PVA-cells had the highest Cd removal percentage (82.7%) at 10mg Cd/l and a biomass loading of 15.4wt.%. Better adsorption ability was obtained when biomass loading was increased, as the highest adsorption capacity of 4.29mg/g was achieved at 33.0wt.% of biomass (initial Cd concentration=100mg/l). An aqueous solution of 0.01M Na3NTA displayed the best desorption efficiency (57–89%) for four A/D cycles, while 51–61% of the original adsorption capacity was retained after regeneration. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: 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 40g/L), giving a RL yield of 7.5 and 4.9g/L, respectively. Meanwhile, sodium nitrate appeared to be the preferable nitrogen source, resulting in a RL production of 8.6g/L. Using NaNO3 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 NaNO3). The RSM analysis gave an optimal concentration of 30.5, 18.1, and 4.9g/L for glucose, glycerol, and NaNO3, respectively, predicting a maximum RL yield of 12.6g/L, which is 47% higher than the best yield (8.6g/L) obtained from preliminary selection tests and single factor experiments (glucose and NaNO3 as the carbon and nitrogen source). The NMR and mass spectrometry analysis show that the purified RL product contained l-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate (RL1) and l-rhamnosyl l-rhamnosyl-β-hydroxydecanoyl-β-hydroxydecanoate (RL2). Meanwhile, HPLC analysis indicates that the molar ratio of RL1 and RL2 in the purified rhamnolipid product was ca. 1:1. [Copyright &y& Elsevier]

Abstract: Inappropriate biological treatment of dimethyl sulfoxide (DMSO) used by opto-electronics and semi-conductor industries would result in production of malodorous compounds, e.g. dimethyl sulfide, methane-thiol and hydrogen sulfide. The best sludge for DMSO biodegradation was obtained from the activated sludge of a chemical company that used to provide DMSO for the above industries. Under the optimal conditions of pH 7.0–8.5 and 30°C, the highest removal efficiency in treatment of 500mgl−1 of DMSO occurred at the rate of 0.078g DMSO per gram suspended solids per day corresponding to 37h for complete DMSO biodegradation in a shake-flask culture. However, the time needed for DMSO biodegradation could be reduced to 16h at the rate of 0.153g DMSO per gram suspended solids per day if a repeated-batch mode was adopted, indicating that an acclimation period is required by the DMSO degraders. The reaction time could further be shortened to less than 10h with 95% removal of the 750mgl−1 DMSO at the maximum rate of 0.909g DMSO per gram suspended solids per day using an oxygen-enriched air-lift bioreactor. No malodorous compounds, such as dimethyl sulfide, were produced revealing that the biodegradation pathway is oxidative and can solve the odor problems common in the biological wastewater treatment plant of the abovementioned industries. [Copyright &y& Elsevier]

Abstract: Biopolymer DYU500 produced from Bacillus subtilis DYU1 was found to have excellent flocculating ability. With the addition of 40mg-DYU500/L and 50mM CaCO3, the optimum temperature for flocculation performance of DYU500 was 30°C, giving the highest flocculating activity and rate of 13.5 and 97%, respectively. Analysis with Fourier transform infrared spectrophotometry (FT-IR), nuclear magnetic resonance spectrometry (NMR) and amino acid identification shows that the DYU500 biopolymer mainly possesses the structure of poly-glutamic acid (PGA). The average molecular weight of DYU500 was about (3.16–3.20)×106 Da as determined by gel permeation chromatography. The major components of biopolymer DYU500 were total sugars, uronic acids, proteins and polyamides (homopolymer of glutamic acid), accounting for a weight ratio of approximate 14.9, 2.7, 4.4 and 48.7% (w/w), respectively. The flocculating activity of DYU500 in the kaolin suspension was markedly stimulated by the addition of bivalent cations Ca2+ or Mg2+ in optimum concentration ranges of about 0.15–0.90 and 0.10–0.90mM, respectively. The synergistic effect of cations was most effective at a weak acidic or neutral pH (6.0–7.0). The flocculating activity of DYU500 linearly decreased with an increase in incubation temperature and the activity was completely lost when heating upon 120°C, arising from the destruction of the polyamides structure of DYU500. Moreover, mechanisms describing the flocculation process with DYU500 were proposed based on the experimental observations. [Copyright &y& Elsevier]

Abstract: Decolorization of azo dye (RED RBN) was carried out experimentally in a liquid–solid fluidized bed reactor (FBR) using polyvinyl alcohol (PVA)-immobilized cell beads as support carriers. The effects of various operating conditions such as bed expansion, cell bead number density, initial dye concentration, hydraulic retention time (HRT), and diameters of immobilized cell beads on the decolorization of azo dye were demonstrated experimentally. It was found that azo dye degradation time reaching initially a steady state decreased with an increase in bed expansion, cell bead number density as well as HRT. The mean cell residence time (θ C) in FBR using PVA-immobilized cell beads increased insignificantly from 1014.1 to 1014.9 days as the HRT increased from 3 to 24h, and thus the impact of convectional reduced θ C could be minimized by using the same polymer as support carriers. In addition, a mathematical model was used to describe the simultaneous diffusion and reaction of azo dye in the FBR. The internal mass-transfer resistance, rather than the film diffusion resistance, played an important role in azo dye utilization in FBR when film modulus (m f) was smaller than 1. The model was employed to analyze and predict both the k L value and the operational efficiency of FBR (which was running in a well-mixed state) in azo dye biodegradation using immobilized cell beads during a steady-state operation. The simulated results corresponded satisfactorily with the experimental data in the azo dye concentration ranging up to 2200mgL−1. [Copyright &y& Elsevier]

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. [Copyright &y& Elsevier]

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 °C under anoxic culture (ANO culture). More than 90% of RED RBN was reduced in color within 8 days at a dye concentration of 3000 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. [Copyright &y& Elsevier]

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. [ABSTRACT FROM AUTHOR]

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 NH4Cl 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. [ABSTRACT FROM AUTHOR]

Abstract: The immobilization of B. subtilis natto Takahashi on alginate matrix was attempted for repeated production of levan. Factors that influence the stability of the immobilized-cell beads and the levan production in the process of fermentation were also investigated. The levan production and the stability of immobilized beads were greatly affected by the sucrose concentration, medium pH, metal ions and agitation speed. When the immobilized cells were cultivated in the optimal conditions, high levan production (70.6g/L) was obtained after 3 d of fermentation and no damaged beads were observed. In the repetitive cultivation, the supplement of organic nitrogen source and control of initial pH was critical for high levan production. Immobilized cells on alginate beads were reused in five successive reaction cycles (each cycle 72h) without any loss of biocatalytic activity and 9 cycles with 72% residual activity. [Copyright &y& Elsevier]

Abstract: 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 and entropy 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 , and E all indicate that the adsorption of direct dyes onto CNTs was a physisorption process. [Copyright &y& Elsevier]

The addition of glycerol, ornithine, and arginine had significant effects on the biosynthesis of clavulanic acid in Streptomyces clavuligerus. Adding ornithine in batch culture could enhance clavulanic acid production but arginine showed little effect. With an addition of 5 mM ornithine to the culture, the CA production (200 mg l−1) was about 2-fold of that without any addition of amino acids (115 mg l−1). In the fed-batch experiments, feeding glycerol could raise clavulanic acid production to 220 mg l−1. In the absence of glycerol, feeding ornithine or arginine only could not enhance the clavulanic acid production. We suggested that glycerol (C3) supply rather than amino acid (C5) supply is rate-limiting. Feeding glycerol with ornithine resulted in further increase in clavulanic acid production to 311 mg l−1, but feeding glycerol with arginine showed little enhancing effect. Feeding ornithine not only provided an enough supply of arginine for clavulanic acid production, but also inhibited the glycerol-utilizing cephamycin biosynthesis. Thus, it could increase the flux of C3 precursor into clavulanic acid. The results reveal that ornithine rather than arginine could enhance effectively clavulanic acid production if the amount of C3 precursor was sufficient. [Copyright &y& Elsevier]

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-1β, 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. [ABSTRACT FROM AUTHOR]

In this paper, we compare the helium-based atmospheric pressure plasma jets (APPJs) with power-ground (PG) and power-floating (PF) configurations by using optical analysis. We find that the PG jet traps plasma between two electrodes (discharge region); thus, the hydroxyl radical intensity is significantly strong in discharge region; however, the plasma intensity in downstream region is relatively weak as compared with that of PF configuration. In contrast, using the APPJ with PF configuration, the hydroxyl radical and nitric oxide are approximately two and three times stronger, respectively, in the downstream region, even though the gas temperature and power consumption are lower. The PF jet successfully eradicates S. mutans and decreases water contact angle by ~40 within 15-s treatment, which demonstrates higher efficient than that of PG jet, and shows highly potential for dental filling demand. [ABSTRACT FROM PUBLISHER]

Even though atmospheric-pressure plasma jet (APPJ) has been shown highly effective in many biomedical applications because of reactive oxygen/nitrogen species (RONS) generated in the discharge, free jet region, and at the interfacial region with the treated surface. However, most of the studies characterized APPJ only in either discharge or free jet region. In this paper, we measured optical emissions of RONS in free jet and plasma/surface interfacial regions of a helium-based dielectric barrier discharge APPJ. The results show that the emissions caused by RONS (nitric oxide, hydroxyl radical, and atomic oxygen) are enhanced 3–5 times at plasma/surface interfacial region as compared with those of free jet region. Some typical sterilization experiments using the current helium-based APPJ show that this helium-based APPJ effectively kills the oral bacteria (S. mutans) in 15 s, which was caused by the cell wall disruption. We believe that measuring the properties at plasma/surface interfacial region is more important than in the free jet region in characterizing APPJ for most realistic applications. [ABSTRACT FROM AUTHOR]

Tandem production of levan and ethanol by microbial fermentation using sucrose substrate was investigated. The tandem process involves fermentation of Bacillus subtilis(natto) Takahashi in a sucrose medium to produce levan, separation of the levan product from glucose by-product by ultrafiltration and fermentation of the glucose remnant from levan production by Zymomonas mobilisto produce ethanol. After cultivation of B. subtilis(natto) Takahashi for 48 h, 56.0 ± 0.6 g l−1of levan was produced in a medium containing 250 g l−1sucrose, which was 45 ± 0.5% yield on available fructose. After removing the cells, the fermentation broth was concentrated by ultrafiltration through a membrane of 5 kDa cutoff. The filtrate which contained 179 ± 3 g l−1of hexose was diluted, supplemented with yeast extract (5 g l−1), (NH4)2SO4(1 g l−1), MgSO4·7H2O (0.5 g l−1), KH2PO4(1 g l−1) and used for alcohol fermentation by Z. mobilis. Incubation of Z. mobilisin the medium containing glucose remnant at 30 °C, pH 5.5, 175 rpm for 120 h gave from 21.1 ± 0.3 to 26.5 ± 0.2 g l−1of bio-ethanol depending on the dilution. The tandem process developed in this study is an eco-friendly process in that the sucrose substrate was fully utilized without wasting any by-products in the process; in addition, two invaluable environmentally-friendly biomaterials (levan and ethanol) were produced. Furthermore, the amount of alcohol required for levan recovery could be reduced to a quarter of that generally used in the conventional precipitation. [ABSTRACT FROM AUTHOR]

Abstract: Agrobacterium sp. was studied for the production of curdlan by conventional one-factor-at-a-time technique and response surface methodology. Factors such as initial pH, urea concentration, sucrose concentration having the greatest influence on the curdlan production were identified. By using response surface methodology (RSM), the curdlan production by Agrobacterium sp. was increased significantly by 109%, from 2.4g/L to 5.02g/L when the strain was cultivated in the optimal medium developed by RSM as compared to conventional one-factor-at-a-time technique. The curdlan production rate of 0.84g/(Lh) was obtained when Agrobacterium sp. was cultivated in the optimal medium developed by RSM, which was the highest curdlan production rate reported to date. The infrared (IR) and NMR spectra, the thermogram of DSC and pattern of X-ray diffraction for the curdlan of the present study were almost identical to those of the authentic curdlan sample (from Alcaligenes faecalis; Sigma). The purified curdlan was a linear polysaccharide composed of exclusively β-(1,3)-glucosidic linkages with the molecular weight of 160,000Da by GPC. The crystalline melting point (T m), glass transition temperature (T g) and X-ray diffraction of the sample indicated low crystallinity in the structure. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The effects on cytokine-stimulating activities of extracellular polysaccharides from submerged cultures with various carbon sources of Tremella mesenterica were investigated in vitro. The predominant sugars in EPS identified in this study were glucose, mannose, xylose, and galactose. The results indicated that the component sugar and uronic acids within the EPS vary with the different carbon sources, a variation which also affects cytokine (interlukin-6 and tumor necrosis factor-α) and nitric oxide production in RAW 264.7 macrophage cells. Xylose and glucose were better carbon sources from the viewpoint of immunomodulatory activity due to the relatively high mannose content in EPS. [Copyright &y& Elsevier]