Efficient Conversion of Cellulose to Glucose, Levulinic Acid, and Other Products in Hot Water Using SO₂ as a Recoverable Catalyst

Cellulose is the most widely distributed source of biomass, and its efficient conversion to a variety of chemicals is important for a sustainable future. In this work, sulfur dioxide (SO₂) dissolved in hot water has been demonstrated to be an efficient catalyst for the selective conversion of cellulose to chemicals such as glucose and levulinic acid. The selectivity of products can be tuned by the SO₂ concentration, temperature, and reaction time. SO₂ acts both as a supply of H⁺ ions through ionization of H₂SO₃ when dissolved in water and as a Lewis acid catalyst that breaks the hydrogen bonds in cellulose. Importantly, SO₂ in the reaction mixture can be recovered completely by stream stripping, thus avoiding the formation of acidic wastewater. This work provides a new, efficient, and environmentally benign way to convert cellulose to chemicals

The effect of NaHS on the mRNA expression of cytokines and chemokines in myometrium of the normal pregnant and LPS-induced preterm labor mice.

<p>Mice accepted two i.p. injections of NS or LPS (0.4mg/kg) with or without NaHS (10mg/kg) at 14.5 dpc. The myometrium was harvested when the LPS-injected mice delivered the first pups. The mRNA levels of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D), and CXCL-15 (E) were measured by real-time RT-PCR and normalized by β-actin. Values are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups). * P<0.05, **P<0.01 compared with vehicle control, #: P<0.05 compared with LPS-injected group.</p

NaHS attenuates LPS-induced activation of ERK1/2 and p65 in myometrium.

<p>The uterine tissues were harvested 1h, 2h, 4h and 5h after LPS and/or NaHS injection. The levels of phosphorylated p65, p65, phosphorylated ERK1/2 and ERK1/2 were determined by western blotting. Phosphorylated p65 (A) and ERK1/2 (B) were normalized by p65 and ERK1/2. Values are presented as mean ± SEM. N = 4. * P<0.05, **P<0.01 compared with vehicle control group, #P<0.05, ##P<0.01 compared with LPS-injected group.</p

NaHS decreases maternal circulatory levels of cytokines and chemokines in LPS-induced preterm labor mice.

<p>The blood was harvested when the LPS-injected mice delivered the first pup. Serum was collected after centrifuge. ELISA was employed to determine the concentration of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D) and CXCL-15 (E). Data are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups).*P<0.05, **P<0.01, ***P<0.001 compared with vehicle control group, #<i>P</i><0.05, ### <i>P</i><0.001 compared with LPS-injected group.</p

Injection of LPS induced preterm labor of mice.

<p>Injection of LPS induced preterm labor of mice.</p

NaHS reverses the LPS-induced leukocytes infiltration into decidua.

<p>Total density of leukocytes in mice maternal-fetus unit was determined by immunostaining for CD45 (common leukocyte antigen). A. Mice injected with vehicle at 14.5 dpc. B. Mice injected with NaHS(10mg/kg) at 14.5 dpc. C. Mice injected with LPS (0.4mg/kg) at 14.5 dpc. D. Mice injected with LPS (0.4mg/kg) and NaHS (10mg/kg) at 14.5 dpc. Arrow heads indicate positively stained leucocytes. Dec, decidua; Pla, placenta; Myo, myometrium.</p

The effect of NaHS on the mRNA expression of cytokines and chemokines in placenta of the normal pregnant and LPS-induced preterm labor mice.

<p>The placenta was harvested when the LPS-injected mice delivered the first pups. The mRNA levels of IL-1β (A), IL-6 (B), TNF-α (C), CCL-2 (D), and CXCL-15 (E) were measured by real-time RT-PCR and normalized by β-actin. Values are presented as mean ± SEM. N = 6 (vehicle and NaHS groups) or 10 (LPS and LPS+NaHS groups). * P<0.05, **P<0.01 compared with vehicle control, #: P<0.05 compared with LPS-injected group.</p

Diagram for the animal model procedure.

<p>Timed-pregnant mice at 14.5 dpc were injected intraperitoneally (i.p.) with LPS with or without NaHS at different doses in 100μl NS twice a day at 8:30 and 11:30. Labor time was considered as the first pup was delivered. GD: gestational day. Black arrow: LPS i.p. Grey arrow: NaHS i.p. White arrow: NS i.p.</p

Application of a Novel Alkali-Tolerant Thermostable DyP-Type Peroxidase from <i>Saccharomonospora viridis</i> DSM 43017 in Biobleaching of Eucalyptus Kraft Pulp

<div><p><i>Saccharomonospora viridis</i> is a thermophilic actinomycete that may have biotechnological applications because of its dye decolorizing activity, though the enzymatic oxidative system responsible for this activity remains elusive. Bioinformatic analysis revealed a DyP-type peroxidase gene in the genome of <i>S. viridis</i> DSM 43017 with sequence similarity to peroxidase from dye-decolorizing microbes. This gene, <i>svidyp</i>, consists of 1,215 bp encoding a polypeptide of 404 amino acids. The gene encoding <i>Svi</i>DyP was cloned, heterologously expressed in <i>Escherichia coli</i>, and then purified. The recombinant protein could efficiently decolorize several triarylmethane dyes, anthraquinonic and azo dyes under neutral to alkaline conditions. The optimum pH and temperature for <i>Svi</i>DyP was pH 7.0 and 70°C, respectively. Compared with other DyP-type peroxidases, <i>Svi</i>DyP was more active at high temperatures, retaining>63% of its maximum activity at 50–80°C. It also showed broad pH adaptability (>35% activity at pH 4.0–9.0) and alkali-tolerance (>80% activity after incubation at pH 5–10 for 1 h at 37°C), and was highly thermostable (>60% activity after incubation at 70°C for 2 h at pH 7.0). <i>Svi</i>DyP had an accelerated action during the biobleaching of eucalyptus kraft pulp, resulting in a 21.8% reduction in kappa number and an increase of 2.98% (ISO) in brightness. These favorable properties make <i>Svi</i>DyP peroxidase a promising enzyme for use in the pulp and paper industries.</p></div

Degradation circles produced by <i>Saccharomonospora viridis</i> on azure B screening plates.

<p>Degradation circles produced by <i>Saccharomonospora viridis</i> on azure B screening plates.</p