Ultrasound-assisted extraction of hemicellulose and phenolic compounds from bamboo bast fiber powder

Ultrasound-assisted extraction of hemicellulose and phenolic compounds from bamboo bast fibre powder was investigated. The effect of ultrasonic probe depth and power input parameters on the type and amount of products extracted was assessed. The results of input energy and radical formation correlated with the calculated values for the anti-nodal point (λ/4; 16.85 mm, maximum amplitude) of the ultrasonic wave in aqueous medium. Ultrasonic treatment at optimum probe depth of 15 mm improve 2.6-fold the extraction efficiencies of hemicellulose and phenolic lignin compounds from bamboo bast fibre powder. LC-Ms-Tof (liquid chromatography-mass spectrometry-time of flight) analysis indicated that ultrasound led to the extraction of coniferyl alcohol, sinapyl alcohol, vanillic acid, cellobiose, in contrast to boiling water extraction only. At optimized conditions, ultrasound caused the formation of radicals confirmed by the presence of (+)-pinoresinol which resulted from the radical coupling of coniferyl alcohol. Ultrasounds revealed to be an efficient methodology for the extraction of hemicellulosic and phenolic compounds from woody bamboo without the addition of harmful solvents.Financial funding from the OeAD-GmbH and the Austrian Federal Ministry of Science, Research and Economy Scientific and Technological Cooperation Programme under the grant number CN 03/2016. The authors would like to thank to Chinese Foundation Key projects of governmental cooperation in international scientific and technological innovation (No. 2016 YFE0115700), the National Natural Science Foundation of China (Grant No.31470509), and the 111 project (No.B17021). The authors would like also to thank to Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by European Regional Development Fund under the scope of Norte2020—Programa Operacional Regional do Norteinfo:eu-repo/semantics/publishedVersio

Environmentally friendly covalent coupling of proteins onto oxidized cellulosic materials

Cellulose is a biodegradable and renewable material that is one of the most abundant biopolymers with many different applications from low value newsprint products to high value biomedical sensor devices. In the last years, the demand of functionalized cellulose for the development of new packaging materials was constantly rising. In this study, a new two-step method for surface functionalization of cellulose sheets and fibers involving oxidation by 2,2,6,6-tetramethylpiperidinyloxyl (TEMPO) followed by coupling of different proteins was investigated. The cellulose oxidation was monitored via FT-IR at 1610 cm 121, photometrically via toluidine blue staining and via titration for the determination of the \u2013COOH group concentration. TEMPO oxidation increased the amount of \u2013COOH groups from around 0.2 to more than 1.4 mmol g 121 when NaClO2/NaClO regeneration was used. The TEMPO/laccase system instead led to 0.7 mmol g 121 of \u2013COOH groups (determined via HCl titration). The oxidation was monitored over time and showed that 50% of the reaction were completed within the first 60 min of reaction time. Coupling of protein-based hydrophobins or bovine serum albumin using the EDAC/NHS system led to the desired increase in hydrophobicity and detection of protein on cellulose. Coupling was investigated using contact angle measurements and SEM microscopy paired with elemental analysis for oxygen and nitrogen. Hence, the coupled hydrophobins led to a significant increase of the initial contact angle by 33% with water drop stability of over 200 s. In contrary, pure cellulose obtained no visible water drop and for surfaces with uncoupled hydrophobins no stable contact angle, with a soaking time dropping to 55 s was achieved. As a result, the thorough study revealed that the new combinatorial approach of surface functionalization and protein coupling led to the successful increase of hydrophobicity

Lysozyme responsive spray-dried chitosan particles for early detection of wound infection

Infections are a severe health issue, and the need for an early point-of-care diagnostic approach for wound infections is continuously growing. Lysozyme has shown a great potential as a biomarker for rapid detection of wound infection. In this study, spray-drying of labeled and derivatized chitosans was investigated for the production of small particles responsive to lysozyme. Therefore, various chitosans, differing in their origin (snow crab, Chionoecetes sp., with medium and low molecular weight or shrimp) were N-acetylated, labeled with reactive black 5, and tested for solubility and spray-drying suitability. Reactive black-5-stained N-acetylated chitosan (low molecular weight, origin crab) was successfully spray-dried, and the obtained particles were characterized regarding size, ζ potential, and morphology. The particles showed an average hydrodynamic radius of 612.5 ± 132.8 nm. ζ potential was measured in the context of a later application as an infection detection system for wound infections in artificial wound fluid (−6.14 ± 0.16 mV) and infected wound fluid (−7.93 ± 1.35 mV). Furthermore, the aggregation behavior and surface structure were analyzed by using scanning electron microscopy and confocal laser scanning microscopy revealing spherical-shaped particles with explicit surface topologies. Spray-dried N-acetylated chitosan particles showed a 5-fold increase in lysozyme-responsive release of dyed chitosan fragments due to the enhanced surface area to volume ratio when compared to non-spray-dried N-acetylated chitosan flakes. On the basis of these results, the study showed the improved properties of N-acetylated spray-dried chitosan particles for future applications for early and rapid infection detection

Glutathione from recovered glucose as ingredient in antioxidant nanocapsules for triggered flavor delivery

Side streams from modern lignocellulose biorefineries have found value-added applications in various industries ranging from food to medical. Here, bioproduction of glutathione from glucose recovered from man-made cellulose fiber production was investigated. Rayon fibers were enzymatically hydrolyzed and the resulting glucose and Zn in the hydrolysate were successfully used for glutathione (15.5 mg L 121) production by an engineered strain of Saccharomyces cerevisiae. Next, out of reduced glutathione (GSH) in combination with human serum albumin (HSA) and silk fibroin (SF), nanocapsules were developed. Production of HSA/SF/GSH nanocapsules was further optimized by experimental design and the resulting nanocapsules were characterized by particle size, zeta potential, chemical properties (secondary structure ratios, crosslinking, and release kinetics) and thermal stability. An average hydrodynamic radius of 462.72 \ub1 73.36 nm and average zeta potential of 1213.67 \ub1 0.01 mV were obtained by optimization using an experimental design approach. Increasing secondary structure ratios for HSA/SF/GSH nanocapsules indicated the successful integration of GSH into the nanocapsule shell by ultrasound induced self-assembly. Regarding possible future application as a cosmeceutical, flavor substances were encapsulated, and the release kinetics of flavor substances were studied, resulting in pH- and viscosity-dependent maximum release rates of 40.45 \ub1 0.35% for menthol and 38.60 \ub1 2.07% for raspberry ketone. Additionally, the radical scavenging properties of the system were evaluated, showing increased scavenging for produced HSA/SF/GSH nanocapsules compared to controls. Therefore, HSA/SF/GSH nanocapsules are seen as a promising new system in cosmeceutical approaches

Soil fertility relates to fungal-mediated decomposition and organic matter turnover in a temperate mountain forest

Fungi are known to exert a significant influence over soil organic matter (SOM) turnover, however understanding of the effects of fungal community structure on SOM dynamics and its consequences for ecosystem fertility is fragmentary. Here we studied soil fungal guilds and SOM decomposition processes along a fertility gradient in a temperate mountain beech forest. High-throughput sequencing was used to investigate fungal communities. Carbon and nitrogen stocks, enzymatic activity and microbial respiration were measured. While ectomycorrhizal fungal abundance was not related to fertility, saprotrophic ascomycetes showed higher relative abundances under more fertile conditions. The activity of oxidising enzymes and respiration rates in mineral soil were related positively to fertility and saprotrophic fungi. In addition, organic layer carbon and nitrogen stocks were lower on the more fertile plots, although tree biomass and litter input were higher. Together, the results indicated a faster SOM turnover at the fertile end of the gradient. We suggest that there is a positive feedback mechanism between SOM turnover and fertility that is mediated by soil fungi to a significant extent. By underlining the importance of fungi for soil fertility and plant growth, these findings furthermore emphasise the dependency of carbon cycling on fungal communities below ground

Soil fertility relates to fungal‐mediated decomposition and organic matter turnover in a temperate mountain forest

Fungi are known to exert a significant influence over soil organic matter (SOM) turnover, however understanding of the effects of fungal community structure on SOM dynamics and its consequences for ecosystem fertility is fragmentary. Here we studied soil fungal guilds and SOM decomposition processes along a fertility gradient in a temperate mountain beech forest. High-throughput sequencing was used to investigate fungal communities. Carbon and nitrogen stocks, enzymatic activity and microbial respiration were measured. While ectomycorrhizal fungal abundance was not related to fertility, saprotrophic ascomycetes showed higher relative abundances under more fertile conditions. The activity of oxidising enzymes and respiration rates in mineral soil were related positively to fertility and saprotrophic fungi. In addition, organic layer carbon and nitrogen stocks were lower on the more fertile plots, although tree biomass and litter input were higher. Together, the results indicated a faster SOM turnover at the fertile end of the gradient. We suggest that there is a positive feedback mechanism between SOM turnover and fertility that is mediated by soil fungi to a significant extent. By underlining the importance of fungi for soil fertility and plant growth, these findings furthermore emphasise the dependency of carbon cycling on fungal communities below ground

Normalized extraction efficiencies (%) for ultrasound-assisted extractions: (A) extraction without pretreatment, (B) extraction with one boiling water pretreatment and (C) extraction with two following boiling water pretreatments.

<p>Normalized extraction efficiencies (%) for ultrasound-assisted extractions: (A) extraction without pretreatment, (B) extraction with one boiling water pretreatment and (C) extraction with two following boiling water pretreatments.</p

Radical conversion of (1) terephthalic acid to (2) 2-hydroxyterephthalic acid [16].

<p>Radical conversion of (1) terephthalic acid to (2) 2-hydroxyterephthalic acid [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0197537#pone.0197537.ref016" target="_blank">16</a>].</p

(A) Relative increase [%] of (+)-pinoresinol measured by LC-ESI-TOF after extraction B (extraction with one boiling water pretreatment) and C (extraction with two following boiling water pretreatments) using an input power of 200 or 400 W with a 15 mm probe depth (B) Dimerization reaction of coniferyl alcohol radicals generated by ultrasound induced radical formation to (+)-pinoresinol; the control consisted on the extraction without ultrasound.

<p>(A) Relative increase [%] of (+)-pinoresinol measured by LC-ESI-TOF after extraction B (extraction with one boiling water pretreatment) and C (extraction with two following boiling water pretreatments) using an input power of 200 or 400 W with a 15 mm probe depth (B) Dimerization reaction of coniferyl alcohol radicals generated by ultrasound induced radical formation to (+)-pinoresinol; the control consisted on the extraction without ultrasound.</p