The Effect of Ball Milling Time on the Isolation of Lignin in the Cell Wall of Different Biomass

Ball milling technology is the classical technology to isolate representative lignin in the cell wall of biomass for further investigation. In this work, different ball milling times were carried out on hardwood (poplar sawdust), softwood (larch sawdust), and gramineous material (bamboo residues) to understand the optimum condition to isolate the representative milled wood lignin (MWL) in these different biomass species. Results showed that prolonging ball milling time from 3 to 7 h obviously increased the isolation yields of MWL in bamboo residues (from 39.2% to 53.9%) and poplar sawdust (from 15.5% to 35.6%), while only a slight increase was found for the MWL yield of larch sawdust (from 23.4% to 25.8%). Importantly, the lignin substructure of ß-O-4 in the MWL samples from different biomasses can be a little degraded with the increasing ball milling time, resulting in the prepared MWL with lower molecular weight and higher content of hydroxyl groups. Based on the isolation yield and structure features, milling time with 3 and 7 h were sufficient to isolate the representative lignin (with yield over 30%) in the cell wall of bamboo residues and poplar sawdust, respectively, while more than 7 h should be carried out to isolate the representative lignin in larch sawdust.

Development of Mycelium Materials Incubating Pleurotus Ostreatus Fungi With Different Substrates Composed of Poplar Sawdust and Cottonseed Hull

The mycelium materials incubating Pleurotus ostreatus fungi based on different substrate compositions were developed, the main components of which were poplar sawdust and cottonseed hull in different proportions. The hyphae on the surface of the samples become dense from appearance due to the addition of cottonseed hull. The Fourier Transforms Infrared analysis revealed that the cellulose, hemicellulose and lignin in substrates of all samples were degraded in different degrees owing to utilization by hyphae growth. The morphology and mechanical properties of the mycelial materials changed as the substrate compositions varied. The difference of properties among all mycelium materials was mainly attributed to the growth of mycelium and different substrate compositions. And the mycelium material (the ratio of poplar sawdust to cottonseed hull was 1) exhibited highest strength and lowest compression set, indicating that its size recovery capability was best. In comparison, the substrate of this material was more favorable to the growth of the mycelium and it showed optimal comprehensive performance among all samples. The mycelium material showed good potentiality for packaging application.

Effect of Different Substrate Mixtures on Volatile Aroma Compounds and Antioxidant Activity of Maitake Mushroom

In the present study, it was aimed to determine the volatile aroma composition and antioxidant activity of Maitake mushroom grown in different substrate mixtures comparatively. Five different substrate mixtures except control were prepared. Total polyphenols and antioxidant activities were specified by Folin-Ciocalteu, FRAP and DPPH methods. Furthermore, analyzes were carried out in both dried and frozen samples. Head Space Solid Phase Micro Extraction technique combined with Gas Chromatography-Mass Spectrometry (GC-MS) was used in the analysis of volatile compounds. In the present study, yield was obtained only from S4 (oak sawdust + wheat stalk + bran at 1:1:1 ratios) and S5 (poplar sawdust + wheat stalk + bran at 1:1:1 ratios) growing mixtures. Therefore, the studies have been continued by comparing only these two mixtures. While the yield in S4 mixture was 55.02 g 1 kg bag-1, it was determined as 124.82 g 1 kg bag-1 in S5 mixture. DPPH analysis results of frozen and dried samples were 7.99±0.08 and 8.19±0.05 µmol TE g-1 DM (S4) and 8.07±0.09 and 8.20±0.06 µmol TE g DM-1 (S5) respectively. In volatile aroma profile analysis, 22 and 32 compounds were detected in S4 and S5, respectively. Ketones were the most found compound groups and its ratio was 68.67% in S4 and 52.37% in S5. The highest percentage among ketones was obtained from 4-nonanone and 3-octanone compounds.

Co-Combustion of Blends of Coal and Underutilised Biomass Residues for Environmental Friendly Electrical Energy Production

This study investigated the co-combustion of the blends of coal and biomass residues from poplar sawdust, rice husk, pine nut shells, and sunflower residues for ecofriendly energy production. Proximate and ultimate analyses and calorific values of the coal and biomass residues were also carried out to evaluate the properties of the coal and biomass residues. The volatile matter in coal was reported as 43.38 wt% and ranged from 56.76 wt% to 80.95 wt% in the biomass residues. The ultimate analysis reported the carbon and sulfur content of coal as 68.7 wt% and 5.5 wt%, respectively. The coal and biomass blends were prepared using different ratios on the thermal basis of coal and biomass given as 100:0, 90:10, 80:20, 70:30, 60:40, and 50:50 by weight percentage. The consequent stoichiometric air requirements for all the blends were also calculated. The results revealed that the combustion of 60:40 of coal and sunflower residue blend was the most efficient blend, resulting in less emission of NOx, SOx, and CO2 in the flue gas compared to the combustion of pure coal. The study revealed a great perspective of the selected biomass residues to blend with coal for environmentally friendly and sustainable energy production.

Aliphatic extractive effects on acetic acid catalysis of typical agricultural residues to xylo-oligosaccharide and enzymatic hydrolyzability of cellulose

Background Xylo-oligosaccharide is the spotlight of functional sugar that improves the economic benefits of lignocellulose biorefinery. Acetic acid acidolysis technology provides a promising application for xylo-oligosaccharide commercial production, but it is restricted by the aliphatic (wax-like) compounds, which cover the outer and inner surfaces of plants. Results We removed aliphatic compounds by extraction with two organic solvents. The benzene–ethanol extraction increased the yield of acidolyzed xylo-oligosaccharides of corncob, sugarcane bagasse, wheat straw, and poplar sawdust by 14.79, 21.05, 16.68, and 7.26% while ethanol extraction increased it by 11.88, 17.43, 1.26, and 13.64%, respectively. Conclusion The single ethanol extraction was safer, more environmentally friendly, and more cost-effective than benzene–ethanol solvent. In short, organic solvent extraction provided a promising auxiliary method for the selective acidolysis of herbaceous xylan to xylo-oligosaccharides, while it had minimal impact on woody poplar.

Effect and optimization of NaOH combined with Fenton pretreatment conditions on enzymatic hydrolysis of poplar sawdust

In this study, the effects and mechanism of pretreatments of three types of chemical reagents combined with Fenton on poplar sawdust were studied and the optimization of enzymatic hydrolysis conditions was conducted using response surface methodology. The results showed that cellulase and hemicellulase had the best hydrolysis effect after NaOH-Fenton pretreatment, which were 63.73% and 29.29%, respectively. The optimal process of poplar substrate was to react in 1% NaOH at 100 ℃ for 1 h, then placed in the Fenton reaction system of 0.2 mmol Fe2+ and 25 mmol H2O2 for 7 h, and finally subjected to enzymatic hydrolysis for 72 h at 52 ℃, with a liquid-solid ratio of 33 and 15 μL/g of β-glycosidase. Under this condition, the enzymatic hydrolysis rates of cellulase and hemicellulase reached 86.65% and 43.9%, respectively. In conclusion, the combination of NaOH and Fenton pretreatment can effectively promote the enzymatic hydrolysis of poplar sawdust, which has great potential in the production of cellulosic ethanol.

Aliphatic Extractive Effects on Acetic Acid Catalysis of Typical Agricultural Residues to Xylo-Oligosaccharide and Enzymatic Hydrolysability of Cellulose

Background: Xylo-oligosaccharide is the spotlight of functional sugar that improves economic benefits of lignocellulose biorefinery. Acetic acid acidolysis technology provides a promising application for xylo-oligosaccharide commercial production, but it is restricted by the aliphatic (wax-like) compounds, which cover the outer and inner surfaces of plants. Results: We removed aliphatic compounds by extraction with two organic solvents. The benzene-ethanol extraction increased the yield of acidolyzed xylo-oligosaccharides of corncob, sugarcane bagasse, wheat straw, and poplar sawdust by 14.79%, 21.05%, 16.68%, and 7.26% while ethanol extraction increased it by 11.88%, 17.43%, 1.26%, and 13.64%, respectively. Conclusion: The single ethanol extraction was safer, more environmentally-friendly and more cost-effective than benzene-ethanol solvent. In short, organic solvents extraction provided a promising auxiliary method for the selective acidolysis of herbaceous xylan to xylo-oligosaccharides, while it had minimal impact on woody poplar.