[en] Corn stover is a common agricultural product in areas with large amounts of corn production. It consists of the leaves and stalks of maize (Zea mays ssp. mays L.) plants left in field following harvest of the cereal grain. Stover makes up about half of the yield of a crop and is similar to straw. This material can be processed as cellulosic ethanol without diverting food for fuel. Unlike grain ethanol, ethanol from stover has a positive effect on food supply and grain price. Diverting corn grain into making fuel has been blamed as one of the causes of the world-wide increase in food prices. The goal of this study was to evaluate the potential of producing cellulose ethanol from corn stover under different seeding densities. The study was an output of the research fellowship of the main author in Kansas State University (KSU), under the USDA International Borlaug Fellowship. Corn stover was collected from the experimental set up of the Agronomy Department at KSU where Manhattan Corn was planted 2X, 1.5X, 1X, 0.5X the recommended 64K plants/ha; and no competition. A randomized complete block design was used with four replications. Stover preparation for fermentation began by drying, grinding to 200 μm, mild acid pre-treatment, and enzymatic hydrolysis using the combined activity of Cellulase and Novozyme under strictly controlled laboratory conditions. Cellulose, hemicelluloses, and lignin contet were determined for each sample using NREL protocols. Glucose and Xylose released per gm of biomass after acid pre-treatment and enzymatic hydrolysis were determined using HPLC. Baker's yeast (S. cereviaccae) was introduced to the biomass following enzymatic saccharification. Fermentation carried out at 300C in a centrifuge running at 100 rpm for 48 hours. Compositional analysis of corn stover fractions was highest in plant population with no competition but remained fairly comparable across planting densities. Cellulos varied from 36 to 42%, hemicellulose, 24-27%, and Lignin, 14-16%. Saccharification efficiency (glucose released from cellulose), ranges from 26-37%. 100% conversion of cellulose to glucose was far from ideal due to presence of lignin in the biomass that restricted due to the presence of lignin in biomass that restricted the full exposure fiber for enzymatic reaction. The recommended seeding rate showed the highest yield of fermentable carbohydrates but did not differ significantly from the other seeding rates. Ethanol conversion based on the glucose released after enzymatic saccharification ranged from 81.42 to 91.67%. Given the saccharification and ethanol conversion efficiencies derived from this experiment, the mean ethanol yield per dry ton biomass of corn stover was approximately 88 L-142 L. Normal seeding density yields 5.66 tons dry corn stover/ha. (author)

[en] Highlights: • The mechanism of radiation degradation of cellulose varies with temperature. • While there are hydrogen bonds, non-chain depolymerization is realized. • The radical center transfer to nearby molecule leads to chain depolymerization. • Thermal dehydration of macroradicals provokes self-disassembly of cellulose. - Abstract: The radiation-induced degradation of cellulose is analyzed taking into account the effect of temperature on the formation and interconversion of macroradicals. Non-chain depolymerization, consisting in the random cleavage of glycosidic bonds, occurs at low and moderate temperatures. As a result, oligomeric polysaccharides are formed in which the C:O:H atomic ratio is only slightly different from the original one. When the hydrogen bonds disappear and the fragmentary radicals are thermally generated, the depolymerization can proceed via the chain mechanism. Another mechanism, which we term self-disassembly, consists in consecutive shortening the polymer chain from its end at pre-pyrolysis temperatures. It is realized via the dehydration of macroradicals and leads to the elimination of monocyclic furans.

No abstract available

[en] Most cellulolytic enzyme blends, either procured from a commercial vendor or isolated from a single cellulolytic microbial secretome, do not efficiently hydrolyze ammonia-pretreated (e.g., ammonia fiber expansion, AFEX) lignocellulosic agricultural crop residues like corn stover to fermentable sugars. Typically reported commercial enzyme loading (30–100 mg protein/g glucan) necessary to achieve >90% total hydrolysis yield (to monosaccharides) for AFEX-treated biomass, within a short saccharification time frame (24–48 h), is economically unviable. Unlike acid-based pretreatments, AFEX retains most of the hemicelluloses in the biomass and therefore requires a more complex suite of enzymes for efficient hydrolysis of cellulose and hemicellulose at industrially relevant high solids loadings. One strategy to reduce enzyme dosage while improving cocktail effectiveness for AFEX-treated biomass has been to use individually purified enzymes to determine optimal enzyme combinations to maximize hydrolysis yields. However, this approach is limited by the selection of heterologous enzymes available or the labor required for isolating low-abundance enzymes directly from the microbial secretomes. Here, we show that directly blending crude cellulolytic and hemicellulolytic enzymes-rich microbial secretomes can maximize specific activity on AFEX-treated biomass without having to isolate individual enzymes. Fourteen commercially available cellulolytic and hemicellulolytic enzymes were procured from leading enzyme companies (Novozymes^®, Genencor^®, and Biocatalysts^®) and were mixed together to generate several hundred unique cocktail combinations. The mixtures were assayed for activity on AFEX-treated corn stover (AFEX-CS) using a previously established high-throughput methodology. The optimal enzyme blend combinations identified from these screening assays were enriched in various low-abundance hemicellulases and accessory enzymes typically absent in most commercial cellulases cocktails. Our simple approach of blending crude commercially available enzyme cocktails allowed a drastic fourfold reduction in total enzyme requirements (from 30 to 7.5 mg enzyme/g glucan loading) to achieve near-theoretical cellulose and hemicellulose saccharification yields for AFEX-CS.

[en] Cellulose nanofibers (CNF) is used in various pharmaceutical applications due to its unique characteristics i.e., biodegradability, mechanical and biological properties. CNF is often produced by spray drying process, knowledge of the drying kinetics in terms of mass and heat transfer on the scale of single droplet is important for process development and model validation. Acoustic levitator was used to study drying process of CNF suspension at different air temperatures and initial CNF concentrations. The unique property of acoustic levitation to hold single droplet contactless in the air, enables to study particle morphology during drying process, calculate evaporation rate and estimate particle porosity. Results show that packed particles result at lower initial concentration and temperature has a moderate influence on mean porosity of CNF dried particles. (Author)

[en] Sodium periodate is as an oxidizing agent that breaks the cellulose ring at the C2-C3 bond of the anhydroglucose units (AGU) by creating two vicinal hydroxyl groups which have the potential to form a Schiff base for further reactions. The objective of this study was to evaluate the effects of different amounts of sodium periodate on the formation and arrangement of hydroxyl groups at the C2-C3 bond of the anhydroglucose units (AGU), which is so-called dihydroxyl cellulose (DHC). Firstly, microcrystalline cellulose (MCC) was sonicated to break down the intermolecular and intramolecular interactions. Then, MCC was oxidized with 3 g and 5 g of sodium periodate to prepare the DHC compounds. The DHC and MCC were characterized by FTIR-ATR, FESEM, TGA, and XRD techniques. The numbers of hydroxyl group of DHC increased with the addition of sodium periodate. Besides, the thermal stability and crystallinity of DHC was found to be higher with the increasing amount of sodium periodate. Lastly, the morphology of DHC was found to be smooth, needle- (1:3) and leaf-like (1:5) structure as compared to the irregular forms of MCC. Difference of thermal stability, crystallinity, and morphological structure of DHC compounds concluded that different amounts of sodium periodate could modify the physicochemical properties of MCC. (author)

[en] In this research, the factors that affect the fading of alpha particle tracks on cellulose nitrate films were investigated. It was found that the track density decreases as temperature and the length of time after the exposure increase. The exposed films were stored at ambient temperature (30±5 degree C), 50 ,70 and 90 degree C for 15-75 minutes and the percentage of track losses were found to be in the range of 0-2, 0-9, 11-22 and 13-30 respectively. The effect of relative humidity between 10-78% was found to be insignificant. When the exposed films were immersed for l hour in water maintained at 25-85 degree C before etching, the track density decreased by 5-59%. The amount of track fading also depends on the energy of the incident alpha particles. The percentage of track loss on films exposed to 5.49 MeV radon alpha particles was found to be lower than that of 6.29 MeV thoron alpha particles. However, the negative ions present in air and the atmospheric pressure in the range of 0.04-10 atm did not show noticeable effect on the density of alpha particle tracks on the films

[en] Poly(lactic acid) (PLA) nanocomposite films reinforced with acetylated bacterial cellulose nanoribbons were prepared by solvent casting. Acetylation of bacterial cellulose (BC) was performed by an innovative and sustainable direct solvent-free route catalyzed by citric acid. The effect of derivatization and its extent on the morphological, optical, thermal and mechanical properties of the nanocomposites was analyzed. Data collected from the above studies showed that acetylation of BC nanoribbons clearly improved the nanofibers dispersion in the PLA matrix with respect to unmodified BC, which in turn resulted in increased transparency and mechanical properties of the nanocomposites produced.

[en] Indonesia is the sixth largest corn producer in the world. The high corn production in Indonesia is correlated with waste corn cob produced. However, corn cob waste is not fully utilized, mainly only disposed and burned that caused environmental pollution. One alternative to utilize of corn cob is to be processed to cellulose based superabsorbent polymer (SAP) hydrogel. In this study, cellulose based hydrogel was prepared using epichlorohydrin (Ech) as cross-linking agent and modified particle size to produce nanohydrogel. The aim of the research was to find out the effect of Ech concentration and cellulose: solvent ratio on the characteristic of nanohydrogel. The treatment tested was Ech concentration of 4%, 16% and 28%; whereas the ratio of cellulose: solvent was 1: 2 (A2) and 1: 4 (A4). Parameters observed were swelling ratio, gel fraction, texture and morphology of the resulted hydrogel. Result showed that the higher the Ech concentration the swelling ratio increasing. The best treatments were nanohydrogel with Ech concentration 28% and cellulose: solvent ratio 1: 2 with characteristics as follows: 514% swelling ratio, 44% gel fraction and 0.33 mJ hardness, with morphology showed higher porosity. This hydrogel has a wide potential as water absorbent material in dry agricultural areas and can be used as fertilizer carrier agent. (paper)

[en] Bamboo viscose or regenerated cellulose fibers were used to check their absorbency properties effect on the wicking and moisture management in gauzes. Bamboo viscose and cotton fibers were spun into five different yarn samples with different fiber proportion by ring spinning. Fifteen different gauze samples were made of these yarn samples. The gauze samples were subjected to wicking test to check the wicking ability. Water vapor transmission test was applied to check the vapor transmission rate. These tests were applied to measure the effectiveness of bamboo viscose, cotton and blended gauze samples in wound healing. Pure bamboo gauzes and gauzes with high content of bamboo fiber, i.e. 75B:25C and 50B:50C, shows better wicking and vapor transmission properties. It makes gauzes with high bamboo viscose suitable for wound care applications because of moisture absorbency. (paper)