Heavy usage of gasoline, burgeoning fuel prices, and environmental issues have paved the way for the exploration of cellulosic ethanol. Cellulosic ethanol production technologies are emerging and require continued technological advancements. One of the most challenging issues is the pretreatment of lignocellulosic biomass for the desired sugars yields after enzymatic hydrolysis. We hypothesized that consecutive dilute sulfuric acid-dilute sodium hydroxide pretreatment would overcome the native recalcitrance of sugarcane bagasse (SB) by enhancing cellulase accessibility of the embedded cellulosic microfibrils. SB hemicellulosic hydrolysate after concentration by vacuum evaporation and detoxification showed 30.89 g/l xylose along with other products (0.32 g/l glucose, 2.31 g/l arabinose, and 1.26 g/l acetic acid). The recovered cellulignin was subsequently delignified by sodium hydroxide mediated pretreatment. The acid–base pretreated material released 48.50 g/l total reducing sugars (0.91 g sugars/g cellulose amount in SB) after enzymatic hydrolysis. Ultra-structural mapping of acid–base pretreated and enzyme hydrolyzed SB by microscopic analysis (scanning electron microcopy (SEM), transmitted light microscopy (TLM), and spectroscopic analysis (X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Fourier transform near-infrared (FT-NIR) spectroscopy, and nuclear magnetic resonance (NMR) spectroscopy) elucidated the molecular changes in hemicellulose, cellulose, and lignin components of bagasse. The detoxified hemicellulosic hydrolysate was fermented by Scheffersomyces shehatae (syn. Candida shehatae UFMG HM 52.2) and resulted in 9.11 g/l ethanol production (yield 0.38 g/g) after 48 hours of fermentation. Enzymatic hydrolysate when fermented by Saccharomyces cerevisiae 174 revealed 8.13 g/l ethanol (yield 0.22 g/g) after 72 hours of fermentation. Multi-scale structural studies of SB after sequential acid–base pretreatment and enzymatic hydrolysis showed marked changes in hemicellulose and lignin removal at molecular level. The cellulosic material showed high saccharification efficiency after enzymatic hydrolysis. Hemicellulosic and cellulosic hydrolysates revealed moderate ethanol production by S. shehatae and S. cerevisiae under batch fermentation conditions.

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Multi-scale structural and chemical analysis of sugarcane bagasse in the process of sequential acid-base pretreatment and ethanol production by Scheffersomyces shehatae and Saccharomyces cerevisiae

The naturally occurring biomolecules present in the plant extracts have been identified to play an active role in the single step formation of nanoparticles with varied morphologies and sizes which is greener and environmentally benign. In the present work, spherical zinc oxide nanoparticles (ZnO NPs) of 2-4nm size were synthesized using aqueous extract of fallen Jacaranda mimosifolia flowers (JMFs), treated as waste. The microwave assisted synthesis was completed successfully within 5min. Thereafter, phase identification, morphology and optical band gap of the synthesized ZnO NPs were done using X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and UV-Visible spectroscopy techniques. The composition of JMFs extract was analyzed by gas chromatography-mass spectrometry (GC-MS) and the ZnO NPs confirmation was further explored with fourier transform infrared spectroscopy (FTIR). The GC-MS results confirmed the presence of oleic acid which has high propensity of acting as a reducing and capping agent. The UV-Visible data suggested an optical band gap of 4.03eV for ZnO NPs indicating their small size due to quantum confinement. Further, facet specific adsorption of oleic acid on the surface of ZnO NPs was studied computationally to find out the impact of biomolecules in defining the shape and size of NPs. The viability of gram negative Escherichia coli and gram positive Enterococcus faecium bacteria was found to be 48% and 43%, respectively at high concentration of NPs.

https://openscholar.dut.ac.za/bitstream/10321/2244/1/Sharma_JPPBP_Vol162_Pg199-207_2016.pdf

Biosynthesis of ZnO nanoparticles using Jacaranda mimosifolia flowers extract: Synergistic antibacterial activity and molecular simulated facet specific adsorption studies.

Surfactant-free carnauba wax dispersion and its use for layer-by-layer assembled protective surface coatings on wood

Novel process for the coproduction of xylo-oligosaccharides, fermentable sugars, and lignosulfonates from hardwood

Hemicellulose isolation, characterization, and the production of xylo-oligosaccharides from the wastewater of a viscose fiber mill

We report a simple method to synthesize spherical and irregular sodium lignosulfonate (SLS)-stabilized zinc oxide (ZnO) nanoparticles using water as a solvent, SLS as a stabilizing agent, and sodium hydroxide as a precipitation agent. The presence of SLS on the surface of ZnO nanoparticles can improve the dispersion of the nanoparticles and make them negatively charged. The negatively charged SLS-stabilized ZnO nanoparticles can be deposited onto cellulose paper through a layer-by-layer (LBL) approach. The resultant cellulose paper samples, coated with ZnO nanoparticles, show good antibacterial activity against both Gram-positive Bacillus subtilis and Gram-negative Escherichia coli.

Preparation and characterization of antibacterial paper coated with sodium lignosulfonate stabilized ZnO nanoparticles

Hot water extraction of aspen woodchips was treated at about 160 °C for 2 h with a liquor-to-solid ratio of 4.76:1 in a 1.84 m3 batch reactor with external liquor circulation. Both five-carbon and six-carbon sugars are obtained in the extraction liquor. Xylose and xylooligomers are the main five-carbon sugar in the hot water extract, which reached a maximum concentration of 0.016 mol/L, and 0.018 mol/L, respectively. Minor monosaccharides including galactose, mannose, rhamnose, glucose, and arabinose are also obtained during the hot water extraction. Rhamnose is the main six-carbon sugar in the extraction liquor, which has a maximum concentration of 0.0042 mol/L. The variations of acetyl groups and formic acid are investigated due to their catalytic effect on the extraction reactions. Zeroth-order kinetics models are found to be adequate in describing the dissolved solids, acids, xylose, and xylooligomers.

https://www.mdpi.com/1996-1073/8/2/1166/pdf

Jipeng Yan

Papers

Preparation and characterization of antibacterial paper coated with sodium lignosulfonate stabilized ZnO nanoparticles

Hot Water Pretreatment of Boreal Aspen Woodchips in a Pilot Scale Digester

Utilization of Hardwood in Biorefinery: A Kinetic Interpretation of Pilot-Scale Hot-Water Pretreatment of Paulownia elongata Woodchips

Kinetics of the Hot-Water Extraction of Paulownia Elongata Woodchips

Quantification of xylooligomers in hot water wood extract by 1H–13C heteronuclear single quantum coherence NMR