Enhanced Enzymatic Saccharification of Tomato Stalk by Combination Pretreatment with NaOH and ChCl:Urea-Thioure in One-Pot Manner

In this study, the mixture of NaOH and deep eutectic solvent (DES) ChCl:UA-TA was firstly used to pretreat waste tomato stalk (TS). The effects of pretreatment time, pretreatment temperature, NaOH dosage, and DES dose were investigated, and the synergistic effects of dilute NaOH and DES combination pretreatment were tested on the influence of enzymatic saccharification. It was found that the relationship between delignification and saccharification rate had a significant linear correction. When TS was pretreated with NaOH (7 wt%)–ChCl:UA-TA (8 wt%) in a solid-to-liquid ratio of 1:10 (wt:wt) at 75 °C for 60 min, the delignification reached 82.1%. The highest yield of reducing sugars from NaOH–ChCl:UA-TA-treated TS could reach 62.5% in an acetate buffer (50 mM, pH 4.8) system containing cellulase (10.0 FPU/g TS) and xylanase (30.0 CBU/g TS) at 50 °C. In summary, effective enzymatic saccharification of TS was developed by a combination pretreatment with dilute NaOH and ChCl:UA-TA, which has potential application in the future

Significant Enhancement of 5-Hydroxymethylfural Productivity from <i>D</i>-Fructose with SG(SiO₂) in Betaine:Glycerol–Water for Efficient Synthesis of Biobased 5-(Hydroxymethyl)furfurylamine

5-Hydroxymethyl-2-furfurylamine (5-HMFA) as an important 5-HMF derivative has been widely utilized in the manufacture of diuretics, antihypertensive drugs, preservatives and curing agents. In this work, an efficient chemoenzymatic route was constructed for producing 5-(hydroxymethyl)furfurylamine (5-HMFA) from biobased D-fructose in deep eutectic solvent Betaine:Glycerol–water. The introduction of Betaine:Glycerol could greatly promote the dehydration of D-fructose to 5-HMF and inhibit the secondary decomposition reactions of 5-HMF, compared with a single aqueous phase. D-Fructose (200 mM) could be catalyzed to 5-HMF (183.4 mM) at 91.7% yield by SG(SiO2) (3 wt%) after 90 min in Betaine:Glycerol (20 wt%), and at 150 °C. E. coli AT exhibited excellent bio-transamination activity to aminate 5-HMF into 5-HMFA at 35 °C and pH 7.5. After 24 h, D-fructose-derived 5-HMF (165.4 mM) was converted to 5-HMFA (155.7 mM) in 94.1% yield with D-Ala (D-Ala-to-5-HMF molar ratio 15:1) in Betaine:Glycerol (20 wt%) without removal of SG(SiO2), achieving a productivity of 0.61 g 5-HMFA/(g substrate D-fructose). Chemoenzymatic valorization of D-fructose with SG(SiO2) and E. coli AT was established for sustainable production of 5-HMFA, which has potential application

Study of high-power broad area distributed-feedback laser

High-power semiconductor laser is commonly used for pump source, but the absorption spectra width of the ion which is pumped by the laser is often small. In order to improve the pumping efficiency of high-power semiconductor laser to solid or fiber laser, the current and thermal drift coefficient of wavelength should be decreased. The influence of grating depth and grating duty cycle with the laser wavelength stabilized effect are analyzed theoretically. The appropriate grating parameter is obtained by experimental verification. And the appropriate laser cavity length is obtained according to the optimized condition. The first broad area distributed-feedback(DFB) laser whose wavelength is well-locked is fabricated interiorly. The broad area DFB laser single emitter with2.4 mm cavity length,100μm stripe width produce continuous-wave output power of400 mW at15°C heatsink temperature and its wavelength is954 nm. The current drift of wavelength on this DFB laser is0.67 nm/A and the thermal drift coefficient of wavelength on this DFB laser is0.046 nm/K

Efficient Synthesis of Furfural from Corncob by a Novel Biochar-Based Heterogeneous Chemocatalyst in Choline Chloride: Maleic Acid–Water

The use of plentiful and renewable feedstock for producing chemicals is fundamental for the development of sustainable chemical processes. Using fish scale as a biobased carrier, a novel biochar SO42−/SnO2-FFS heterogeneous chemocatalyst was prepared to catalyze furfural production from xylose-rich corncob-hydrolysates obtained from acid hydrolysis of corncob in a deep eutectic solvent (DES)–water system. By characterizing the physical as well as chemical properties of SO42−/SnO2-FFS by NH3-TPD, FT-IR, XPS, XRD, and SEM, it was shown that the chemocatalyst had Lewis/Brönsted acid centers, and its surface roughness could be well expanded to contact substrates. The corncob was initially hydrolyzed at 140 °C to obtain xylose-rich hydrolysate. Subsequently, SO42−/SnO2-FFS (3.6 wt.%) was used to catalyze the corn cob hydrolysate containing D-xylose (20.0 g/L) at a reaction temperature of 170 °C for 15 min. Additionally, ZnCl2 (20.0 g/L) was added. Ultimately, furfural (93.8 mM, 70.5% yield) was produced in the deep eutectic solvent ChCl:maleic acid–water (DESMLA–water = 10:90, v/v). A synergistic catalytic mechanism for transforming xylose-rich corncob-hydrolysate into furfural and byproducts were proposed using SO42−/SnO2-FFS as a chemocatalyst in DESMLA–water containing ZnCl2. Consequently, the efficient use of biochar SO42−/SnO2-FFS chemocatalysts for the sustainable synthesis of biobased furan compounds from biomass holds great promise in the future

Valorization of Waste Lignocellulose to Furfural by Sulfonated Biobased Heterogeneous Catalyst Using Ultrasonic-Treated Chestnut Shell Waste as Carrier

Recently, the highly efficient production of value-added biobased chemicals from available, inexpensive, and renewable biomass has gained more and more attention in a sustainable catalytic process. Furfural is a versatile biobased chemical, which has been widely used for making solvents, lubricants, inks, adhesives, antacids, polymers, plastics, fuels, fragrances, flavors, fungicides, fertilizers, nematicides, agrochemicals, and pharmaceuticals. In this work, ultrasonic-treated chestnut shell waste (UTS-CSW) was utilized as biobased support to prepare biomass-based heterogeneous catalyst (CSUTS-CSW) for transforming waste lignocellulosic materials into furfural. The pore and surface properties of CSUTS-CSW were characterized with BET, SEM, XRD, and FT-IR. In toluene&ndash;water (2:1, v:v; pH 1.0), CSUTS-CSW (3.6 wt%) converted corncob into furfural yield in the yield of 68.7% at 180 &deg;C in 15 min. CSUTS-CSW had high activity and thermostability, which could be recycled and reused for seven batches. From first to seventh, the yields were obtained from 68.7 to 47.5%. Clearly, this biobased solid acid CSUTS-CSW could be used for the sustainable conversion of waste biomasses into furfural, which had potential application in future

An asymmetric broad waveguide structure for a 0.98-μm high-conversion-efficiency diode laser

A novel asymmetric broad waveguide diode laser structure was designed for high power conversion efficiency (PCE). The internal quantum efficiency, the series resistance, and the thermal resistance were theoretically optimized. The series resistance and the thermal resistance were greatly decreased by optimizing the thickness of the P-waveguide and the P-cladding layers. The internal quantum efficiency was increased by introducing a novel strain-compensated GaAs_0.9P_0.1/InGaAs quantum well. Experimentally, a single 1-cm bar with 20% fill factor and 900 μm cavity length was mounted P-side down on a microchannel-cooled heatsink, and a peak PCE of 60% is obtained at 26.3-W continuous wave output power.The results prove that this novel asymmetric waveguide structure design is an efficient approach to improve the PCE

Synthesis of 5‑Hydroxymethyl-2-furfurylamine from Bread Waste via Two-Step Reaction

5-Hydroxymethyl-2-furfurylamine (HMFA) is an important furan chemical, which plays an important role in diuretics, antihypertensive drugs, and preservatives and can be obtained by amination of 5-hydroxymethylfurfural (HMF). In this study, bread waste (BW) was chemoenzymatically transformed into HMFA via a one-pot two-step method through the tandem catalysis of deep eutectic solvent betaine/formic acid (chemical catalyst) and Escherichia coli HILF cells (biocatalyst). First, the catalyst betaine/formic acid (10.0 wt %) was applied to catalyze BW (20.0 g/L) at 180 °C for 80 min, and the HMF yield reached 0.269 g HMF/g BW. Furthermore, coexpression of ω-transaminase HNIL [His (H) at AT210 was mutated to Asn (N) and Ile (I) at AT77 was mutated to Leu (L) in Aspergillus terreus transaminase] and lactate dehydrogenase (LDH) coupled with formate dehydrogenase (FDH) was utilized for biological amination and coenzyme regeneration, and the recombinant E. coli HILF was constructed by constructing a three-enzyme cascade catalytic reaction system. Using whole cells of HILF as a biocatalyst, the additional amount of d-alanine supplemented into the biological amination reaction was apparently reduced compared with that of the original transaminase. HILF cells could convert BW-derived HMF into HMFA (90.0% yield), and the yield was 0.243 g HMFA/g BW within 6 h. This hybrid strategy apparently reduced the dosage and cost of amine donors in biological amination and also laid the foundation for large-scale production of HMFA from BW

High power885 nm laser diodes with graded optical expand structures for small divergence angle

In order to decrease the generated heat during pumping laser crystals, and enhance the efficiency of optical coupling with pumped materials,885 nm high power laser diodes with small vertical divergence angle were theoretically designed and fabricated. By means of introducing a grade optical expand layer into cladding layers, and combining optimized design the epitaxy material structure, the vertical divergence angle of devices was effectively decreased. AlGalnAs/AlGaAs quantum wells structure was used to increase the compressive strain, optical gain coefficient was enhanced, and material composition and thickness of quantum wells were optimized theoretically. The epitaxy material was prepared by LP-MOCVD technology, and the standard1 cm laser bar was fabricated. Measured results indicate that the vertical divergence angle of devices is decreased to17.6°, the output power and slope efficiency are20.1 W and1.05 W/A respectively, and the corresponding center wavelength is888.2 nm