Volume 9 Issue 1

Production of bioethanol from lignocellulosic biomass is difficult due to differences in the feedstock. There is a need for an efficient pretreatment method that not only reduces the total process economy but also increases the total process efficiency. Following microwave-NaOH pretreatment of peanut shells in the presence of the cationic ionic surfactant cetyltrimethylammonium bromide (CTAB) and enzymatic hydrolysis, the pretreatment efficiency was significantly enhanced. The structural changes before and after pretreatment were detected by Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). FTIR and SEM showed the differences between the untreated and pretreated samples. The XRD profile showed that the degree of crystallinity was higher for pretreated materials than for untreated ones. These changes also verified the effect of CTAB during pretreatment of peanut shells.

Conversion of cellulose into fermentable sugars for ethanol production is currently performed by enzymatic hydrolysis catalyzed by cellulases. The cellulases are produced by a wide variety of microorganisms, playing a major role in the recycling of biomass. The endo-1,4-β-glucanase (CelB31C) from Bacillus amyloliquefaciens B31C, isolated from compost and previously selected on the basis of highest cellulase activity levels among Bacillus isolated, was characterized as being a potential candidate for a biocatalyst in lignocellulose conversion for second-generation bioethanol production. The aim of this work was to evaluate the changes in production of enzymatic activity of the endo-1,4-β-glucanase (CelB31C) and the expression of its gene (bglC) using a carboxymethylcellulase activity assay and qRT-PCR analysis, respectively, during growth of B. amyloliquefaciens B31C on different cellulose sources: carboxymethylcellulose (CMC), pure cellulose from Arundo donax, pretreated Arundo donax biomass (Chemtex), and microcrystalline cellulose (Avicel). The results showed that both the expression of bglC gene and the enzymatic activity production are related to the type of cellulose source. The strain showed a high enzymatic activity on lignocellulosic biomass and on microcrystalline cellulose. Furthermore, the highest gene expression occurred during the exponential phase of growth, except in the presence of Avicel.

To evaluate the biofuel potential of bagasse, an abundant co-product in sugarcane-based industries, the effect of steam explosion on the efficiency of enzymatic saccharification and anaerobic digestion was studied. Bagasse was steam exploded at four different severity levels, and the impact of pretreatment was evaluated by analyzing the release of glucose after enzymatic saccharification with Cellic CTec2 and by analyzing methane production during anaerobic batch digestions. Increasing the severity of pretreatment led to degradation of xylan and the formation of pseudo-lignin. The severity of pretreatment was correlated with the enzymatic release of glucose; at optimal conditions, > 90% of the glucan was released. The highest methane yield (216 mL/gVS) was 1.3 times higher than the yield from untreated bagasse. More importantly, the pretreatment dramatically increased the rate of methane production; after 10 days, methane production from pretreated material was approximately twice that of the untreated material. To assess the possibility of developing combined processes, steam-exploded bagasse was enzymatically pre-hydrolyzed and, after the removal of released sugars, the remaining solid was subjected to anaerobic digestion. The results indicated that, in terms of total heating value, combined ethanol and biogas production is as beneficial as producing only biogas.

Five steroidal sapogenins (tigogenin, neotigogenina, hecogenin, gloriogenin, and dehydrohecogenin) were characterised by gas chromatography coupled with mass spectrometry (GC-MS) from a hydrolysed extract of sisal waste. In addition, pure hecogenin, an important raw material for the pharmaceutical industry, was obtained from this waste by selective liquid-liquid extraction of saponins with only hecogenin as aglycone, followed by acid hydrolysis. The yield of pure hecogenin was 460 mg.Kg-1 of sisal waste.

In the process of acid hydrolysis of cellulose, hydrolyzing the amorphous regions while retaining the crystalline regions is the key technology for obtaining microcrystalline cellulose products. This paper investigated the influence of FeCl3 on selective acid hydrolysis of crystalline regions and amorphous regions of cellulose. X-ray diffraction data indicated that FeCl3 can enhance the selectivity of acid hydrolysis for amorphous regions of cellulose, thus improving the crystallinity of hydrocellulose. Meanwhile, the crystalline structure did not change. Response surface methodology (RSM) was employed to optimize the crystallinity of hydrocellulose with respect to FeCl3 concentration, HCl concentration, reaction time, and temperature, and the relevant mathematical regression equation model was established. Under optimal conditions, the crystallinity of hydrocellulose was as high as 63.59% at 88.28 °C, 2.46 M HCl, 0.4 M FeCl3, and reaction duration of 64.02 min, which was in agreement with the predicted value.

This paper deals with splinter size analysis of beech wood, considering the angular tool of the cutter and also the physical and mechanical wood properties substantially influencing wood processing technology. Particle size analysis was conducted by sieving the samples using a set of laboratory sieves, with subsequent determination of the individual fraction shares. The results have been compared with respect to the possibility of wood waste separation and filtration, and its subsequent utilization, above all, in the production of agglomerated materials and production of wood briquettes and pellets. The most frequently occurring fractions in native beech samples range between 5 and 8 mm and between 2 and 5 mm, while powder fractions below 125 μm were found in less than 1% of investigated samples. The most frequently occurring fractions in thermally modified beech wood ranged from 0.5 to 1 mm, and the share of powder wood particles below 125 μm was less than 4%.

Precipitated calcium carbonate (PCC) is a filler that is widely used for papermaking, and lime sludge is a special type of PCC recovered from the black liquor from kraft pulping. There has been some concern that lime sludge may interfere with the development of paper’s hydrophobicity in comparison with commercial PCC and ground calcium carbonate (GCC) due to the presence of impurities when alkyl ketene dimer (AKD) is used as the sizing additive. In this work, fillers with different particle size distributions were prepared, and the effects of particle composition on surface chemistry of fillers, adsorption for AKD, sizing degree of final paper sheets, and retention behavior of fillers were evaluated. The results showed that, through matching different particle size distributions for lime sludge fillers, the negative zeta potential decreased from -26.2 mV to -20.8 mV, the specific surface area decreased from 15.0 m2/g to 9.1 m2/g, and total pore volume decreased from 0.037 cm3/g to 0.026 cm3/g, which was favorable for the low adsorption for AKD. Consequently the sizing effect of filled paper was improved. Moreover, the retention rate also was increased by changing the particle size distribution of lime sludge.

The forest products industry has an opportunity to reduce energy costs using energy management practices, thereby boosting its global competitiveness. Increasing manufacturing costs have contributed significantly to the decline of the forest products manufacturing industries in the U.S.; these increasing costs limit manufacturers’ abilities to compete with their global competitors. U.S. companies are continually improving their products, processes, finances, and business practices to better compete with global marketplaces; however, they may not be seizing all of the opportunities available through more efficient energy consumption practices. By eliminating non-valued added activities, lean thinking is an example of one tool that may improve performance and reduce costs. A case study was conducted at a cabinet manufacturer in Virginia to examine the impact of lean thinking on the consumption of electricity in the manufacturing process. An energy management system was used to provide rapid feedback on electrical energy consumption for production operations. Significant changes were observed after implementing energy reduction practices identified by lean thinking tools.

Lignins from a steam explosion process in crude and purified forms and modified sulphur-free commercial lignin (Protobind 3000®) were characterised to establish their chemical compositions. Then, the lignins were tested again after treatment with hexamethylenetetramine (HMT). The resulting products were used to make rubber composites, and their mechanical properties were compared to rubber composites made with carbon black to test the possibility of using HMT-treated lignins as a partial replacement for carbon black in the production of rubber composites. In the crude lignin, a significant amount of impurities were detected, such as ash and residual polysaccharides, and these substances interfered in filler-elastomer interactions. The purified lignin maintained a high content of strongly polarised hydroxyl groups that interfered with the interaction of the filler and elastomer, resulting in low performance. Improvements in the mechanical properties were observed using Protobind 3000® lignin or purified lignin with HMT added during mixing with the rubber. Finally, the mixing of HMT-treated lignin with elastomers resulted in composites with higher reinforcement abilities compared to previously described rubber composites. However, in all samples, a poor and unsatisfactory dispersion of lignin in the polymeric matrix was observed. This is likely due to the incompatibility of lignin with the hydrophobic rubber, resulting in lower performances compared to the carbon black.

This study investigated the effect of kenaf parts (kenaf whole stem, kenaf core, and kenaf bast) on the mechanical and physical properties of single-layer and three-layer particleboards made from kenaf (Hibiscus cannabinus L.) and rubberwood (Hevea brasiliensis). The findings showed that the use of kenaf whole stem, which consists of both core and bast, had a positive effect on the modulus of rupture (MOR), modulus of elasticity (MOE), internal bond (IB), permeability, thickness swelling (TS), and water absorption (WA) values of single-layer and three-layer panels. Single-layer admixture panels made from a combination of 70% rubberwood and 30% kenaf had greater strength and stability than single-layer homogeneous panels. The presence of rubberwood particles on surface layers significantly improved the elastic properties of three-layer panels. Panels with kenaf whole stem in the middle layer had better performance than panels with kenaf core. The MOE values of 35RW-30KWS-35RW panels were 56% and 79%, which were higher than those comprising single layers of 100% KWS and 100% KC, respectively. This study suggests that kenaf whole stem is the preferred material to be used in particleboard manufacture incorporated with rubberwood as an admixture for three-layer panels.