Volume 14 Issue 3

Cellulose of corn stalk pulp fines and stalk pith were dissolved in an ionic liquid solvent system (DMAc/LiCl) and then regenerated to form films. The mechanical properties and Tmax of pulp fines/regenerated cellulose (RC) films were higher than that of the corresponding films from stalk pith. As the ratio of small particles was high in the pulp fines, the elongation at breakage of their RC films also increased to 12.9%. Thus, pulp fines were suitable for prepared regenerated cellulosic materials.

Wood fibers from seven Eucalyptus species were collected to investigate the relationships among species, fiber biometry, and nanomechanical properties. The results indicated significant differences in wood density, coarseness, fiber length, fiber width, and cell wall thickness among the different Eucalyptus species. The nanomechanical properties of the S2 cell wall layer also showed significant differences among the Eucalyptus species. The elasticity modulus ranged from 16 to 19 GPa, the hardness spanned 0.24 to 0.31 GPa, and the ductility ratio was between 54 and 68. Moreover, significant correlations were observed for hardness versus cell wall thickness (r = 0.87), and elasticity modulus versus crystallinity index (r = 0.80) and crystallite size (r = 0.68). Among the evaluated species, E. dunnii showed the highest elasticity modulus, highest hardness average, and the highest crystallinity index. The range of nanomechanical values indicated that Eucalyptus wood fibers are suitable for the development of new composite materials or engineering products by selecting the most adequate species for each use according to its properties.

Agricultural residues are among the most important and abundant biomass resources in the world. This study aimed to highlight the characterization of common agricultural residues in China. Six indicators, including biomass, cellulose, hemicelluloses, lignin, caloric value, and ash, were selected to evaluate agricultural residue for its potential energy utilization using grey relational analysis. The results showed that residues of grain crops, including corn (439.1 million tons, 46.6%), rice (207.1 million tons, 21.5%), and wheat (150.7 million tons, 16.0%) were the top three agricultural residues, accounting for 84.1% of total Chinese agricultural residues. Among the agricultural residue samples, rice, wheat, and corn exhibited relatively low ash content; and sugarcane, cotton, and rape residue exhibited low lignin content. Rape, corn, and hemp showed higher cellulose content; and rice, wheat, and corn exhibited higher hemicellulose content. Among the agricultural residues, hemp, corn, and sugarcane showed higher caloric value compared to other residues. According to the grey relational analysis, these combined properties have shown that corn, rice, and wheat can act as potential candidates for energy utilization. The evaluation results were essentially identical to the performance of agricultural residues. Therefore, the comprehensive evaluation of agricultural residues provides sound scientific evidence for their use in energy production.

Lignin-carbohydrate complexes (LCC) were isolated from poplar wood after ball-milling for 48 h and 72 h. The water-insoluble LCC-48 and LCC-72 were fractionated. Porous spherical composite bio-carriers were prepared by liquid-nitrogen freezing using the water-insoluble LCCs and cellulose nanocrystals (CNC). Fourier transform infrared spectroscopy (FT-IR) showed that the bio-carriers were composed of lignin moieties and polysaccharide units. Scanning electron microscopy (SEM) revealed that the outer surface and cut surface of the spherical carrier had many pores. The specific surface areas of the LCC-72/CNC and the LCC-48/CNC composite carriers were 24.2 m2/g and 28.9 m2/g, respectively, while their pore sizes were 28.6 nm and 33.6 nm, respectively. Both carrier samples had good stability at pH 4.6 to 9.5 for about 50 days. Human hepatocytes were cultured in vitro with the bio-carriers and the cells grew well. A large number of cells adhered to the porous bio-carriers, and the cells of the experimental group to which the carriers were added exhibited higher metabolic activities. The CNC improved the biocompatibility for human hepatocytes. In summary, spherical bio-carriers prepared from LCC/CNC composite displayed high biocompatibility and have potential applications in liver tissue engineering.

Corn is a plant that can be used as a potential source of biomass for various biomaterial applications. Thermoplastic corn starch and corn hull, husk, and stalk fibers were extracted from different corn plant parts. The chemical composition, physical properties, thermal stability, crystallinity index, and surface morphology of the extracted samples were characterized on a powder basis. The corn husk and corn starch revealed an excellent combination of properties. Corn husk provided the highest cellulose content as well as the most favorable surface morphology. Corn starch revealed acceptable amylose content and tolerable thermal stability. The cellulose and starch demonstrated an excellent correlation between the function and structure of biomolecules. Hence, both corn starch and husk have potential for use in many applications of the biomaterial.

Fractionation of corn stover (CS) was carried out by bisulfite pretreatment in order to improve the production of bioethanol and high-value chemicals. Firstly, the optimum bisulfite pretreatment conditions of CS (170 C, 30 min, 7% NaHSO3, 1% H2SO4) were identified. Next, a biorefinery process of bisulfite pretreatment for CS was proposed. CS was separated into solid and liquor components using such pretreatment. The solid components were employed for bioethanol production by quasi-simultaneous saccharification and fermentation (Q-SSF). The bisulfite liquor was fractionated into hemicellulosic sugars and lignin by different types of resins. It was shown that CS components could be effectively fractionated through bisulfite pretreatment in combination with resin separation to produce bioethanol, hemicellulosic sugars, and lignosulfonate.

A solution-type TiO2-based photocatalyst for the decomposition of volatile organic compounds was synthesized using a modified sol-gel method under either alcohol (ethanol or isopropanol) or aqueous conditions. Anatase-type TiO2 was successfully synthesized with additional hydrothermal treatment using either type of medium. However, the aqueous condition for TiO2 synthesis was more convenient for the formation of anatase-type TiO2. Based on X-ray diffraction analysis data, the optimal hydrothermal treatment temperature was 80 °C for anatase-type TiO2 formation; at temperatures below 80 °C or above 90 °C, mostly rutile-type TiO2 was formed. The synthesized anatase-type TiO2 solution was applied to the surface of carbonized medium-density fiberboard (c-MDF). The anatase-type TiO2 on c-MDF showed good maintenance of toluene decomposition performance even after repeated use for 14 weeks.

As the demand increases for low energy green buildings, such as passive housing, the development of new insulation systems based on natural materials is underway. In this study, 20-mm-thick wood fiber insulation board (WIB) samples of different densities were prepared using melamine-formaldehyde-urea (MFU) resin adhesives. The resin contents were fixed at 35% and the target densities were 0.10 g/cm3, 0.15 g/cm3, 0.20 g/cm3, and 0.25 g/cm3. The thermal conductivities of the WIBs gradually increased as the density increased. The formaldehyde (HCHO) emissions of all the WIBs indicated that they were of “Super E0” (SE0) grade, but the quantity of the HCHO emissions slightly increased as the density increased. The thickness swelling of all the WIBs was stable at less than 3%, and the bending strength linearly increased as the WIB density increased. A notable decrease in the water absorption rate was observed between the lower and higher density WIB samples. Based on the results of the cone calorimeter tests, the carbonization depth ratio and the weight loss rate remarkably decreased as the density increased. Therefore, the optimum WIB density was in the range of 0.15 g/cm3 to 0.20 g/cm3 to provide adequate insulation performance as well as human and structural safety.

Penicillium citrinum NCIM-1398 is a co-producer of endo β-1,4-glucanase, xylanase, and amylase enzymes. The synergistic effect of the enzymes present in the cocktail was found to be advantageous in deinking white mixed office waste (MOW) paper. Enzymatic deinking of MOW reduced the dependence on chemicals by up to 50% during chemical deinking and improved optical properties compared with the chemical deinking process. The chemi-enzymatic approach improved pulp brightness by 12.6% compared with MOW pulp. The ERIC (Effective residual ink concentration) value was reduced by up to 39.2%, whereas the strength properties of tear index, tensile index, and burst index achieved gains of 3.2%, 9.9%, and 6.2%, respectively, compared with the control. Whereas chemi-enzymatic treatment showed a reduction of 67.1% in COD and 61.8% in BOD, and there was an increase of 15.4% in total solid of effluents respectively, compared with the respective controls. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD) studies revealed that the pulp was modified by enzymatic and chemi-enzymatic treatments, which facilitate ink removal during deinking of pulp.

Manganese peroxidase (MnP), a crucial enzyme in biodegradation of lignin, is synthesized by most white rot fungi. To obtain novel enzymes with superior biodegradation potential, MnP-producing wild isolates were evaluated for their ability to degrade recalcitrant azo dyes, sulfonephthalein dyes, and kraft lignin. Of 30 wild isolates screened, 18 tested positive for lignin modifying enzymes (LMEs). Thirteen of these isolates were positive for both laccase and MnP, whereas four produced only laccase, and one produced lignin peroxidase alone. The isolates were identified as Clitopilus scyphoides MH172162 (AGUM004), Ganoderma rasinaceum MH172163 (AGUM007), and three Schizophyllum species: MH172164, MH172165, and MH172166 (KONA001, AGUM0011, and AGUM021). The Fourier-transform infrared spectroscopy (FTIR) analysis of dye degradation and kraft lignin samples with AGUM004 and AGUM007 revealed biotransformation. The former could not completely degrade Reactive Black 5 and bromocresol green, but it could completely (100%) decolorize bromophenyl blue, bromothymol blue, and Remazol brilliant blue R. The latter efficiently degraded almost all tested dyes. Both degraded kraft lignin. The screened hyper MnP-producing wild AGUM004 and AGUM007 were shown to be potential dye degraders in addition to having lignin degrading abilities.