Optimal Method for Production of Amorphous Cellulose with Increased Enzymatic Digestibility

In this paper, a simple and cheap method for producing of amorphous cellulose was studied by treating the initial cellulosic material (MCC and waste paper) with a cold solvent, such as aqueous solution of 7% NaOH/12% Urea, at the various ratios of the solvent to cellulose (v/w) (R). If was found that after treatment of cellulose materials with the solvent at R ≥5, a completely amorphous cellulose (AC) is formed. Due to high digestibility, the AC with concentration of 50 g/L is converted to glucose almost completely for 48 h under the action of cellulolytic enzyme CTec-3 with a dose of 30 mg/g solid sample. Such sample can be used as an amorphous standard in the study of crystallinity degree and enzymatic hydrolysis of various types of cellulose and lignocellulose. It was found that enzymatic saccharification is most advantageous to carry out at elevated concentrations of AC, 150 g /L. Due to high cost of MCC, it is preferable to use a cheap cellulose raw material, such as mixed waste paper (MWP), for the commercial production of AC and glucose. The resulting glucose can find application in biotechnology as a promising nutrient for various microorganisms

Study of Structural Characteristics of Cellulose Esters with Different Degrees of Substitution

In this article, structural characteristics of amorphous mono-, di-, andtri-substituted esters of cellulose have been studied. These esters weresynthesized under homogenous conditions using anhydrides of variousaliphatic acids. The specific gravity of the highly substituted samples wasmeasured by a pycnometric method in the aqueous medium. To calculatethe molar, Van der Waals, and free volumes, as well as the packingcoefficient of amorphous esters the method of additive contributions ofpartial volumes of atoms and atom groups in the volumes of polymerswas used. Based on the molar volume, also specific gravity of celluloseesters was calculated. The coincidence of calculated and experimentalcharacteristics was shown. In addition, the relationship between glasstransition temperature and free volume was found for the esters. Thetheoretical equations were derived, which provide predicting the structuralcharacteristics of cellulose esters with different degrees of substitution

Study of Hydrophilic Properties of Polysaccharides

In this research, the structural characteristics, specific surface area, sorption of water vapor, and wetting enthalpy of various polysaccharides (cellulose, hemicelluloses, starch, pectin, chitin, and chitosan) have been studied. It was confirmed that crystallites are inaccessible for water, and therefore water molecules can interact only with polar groups in noncrystalline (amorphous) domains of biopolymers. The isotherms of water vapor sorption for various polysaccharides had sigmoid shapes, which can be explained by the absorption of water molecules in heterogeneous amorphous domains having clusters with different packing densities. The method of contributions of polar groups to sorption of water molecules was used, which allowed to derivate a simple calculating equation to describe the shape of sorption isotherms. The wetting of biopolymers with water was accompanied by a high exothermic thermal effect, in direct proportion to the amorphicity degree. The sorption values and wetting enthalpies of amorphous domains of biopolymers were calculated, which allowed to find the hydrophilicity index and compare the hydrophilicity of the various polysaccharides

Recent Findings and the Energetic Potential of Plant Biomass as a Renewable Source of Biofuels – A Review

Nowadays the main sources of energy are petroleum, coal, and natural gas. However, these fossil sources are not reproduced in nature; on a human timescale their reserves are exhausted permanently and run down. Considerable attention in recent years has been given to plant biomass, which in contrast to the fossil sources is continuously renewed in nature. In this critical review the use of non-edible plant biomass for production of various kinds of biofuels is considered. To generate energy, plant biomass either can be burned directly or it can be used after its conversion into carbonized solid fuel (e.g. biochar), liquid fuels (bioethanol, biodiesel, bio-oil), or gases (biogas). Among various biofuels, production of bioethanol has potential to be the most attractive if recent technological advances become implemented, such that the co-production of ethanol and valuable byproducts can be combined together with recycling of solid and liquid wastes. A comparative analysis of energetic potential of biomass and various kinds of biofuels revealed that the most efficient way to produce energy is by direct burning of the plant biomass in a pelletized form, while the burning of such amount of the solid, liquid, or gaseous biofuel, which can be obtained from the plant material, gives a much smaller energetic effect. Novel types of pellets, as well as solid/liquid biofuels, having improved fuel characteristics are described