The properties of enzyme-hydrolyzed cellulose in aqueous sodium hydroxide

A green and efficient technology for the degradation of cellulosic materials: structure changes and enhanced enzymatic hydrolysis of natural cellulose pretreated by synergistic interaction of mechanical activation and metal salt

A new technology for the pretreatment of natural cellulose was developed, which combined mechanical activation (MA) and metal salt treatments in a stirring ball mill. Different valent metal nitrates were used to investigate the changes in degree of polymerization (DP) and crystallinity index (CrI) of cellulose after MA+metal salt (MAMS) pretreatment, and Al(NO3)3 showed better pretreatment effect than NaNO3 and Zn(NO3)2. The destruction of morphological structure of cellulose was mainly resulted from intense ball milling, and the comparative studies on the changes of DP and crystal structure of MA and MA+Al(NO3)3 pretreated cellulose samples showed a synergistic interaction of MA and Al(NO3)3 treatments with more effective changes of structural characteristics of MA+Al(NO3)3 pretreated cellulose and substantial increase of reducing sugar yield in enzymatic hydrolysis of cellulose. In addition, the results indicated that the presence of Al(NO3)3 had significant enhancement for the enzymatic hydrolysis of cellulose.

Synthesis of cellulose dehydroabietate in ionic liquid [bmim]Br

A new type of cellulose derivative, cellulose dehydroabietate (CDA), was synthesized by the O-acylation reaction of cellulose with dehydroabietic acid chloride (DHAC) using ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br) as a solvent and 4-dimethyl-aminopyridine (DMAP) as a catalyst. The resulting CDA was characterized by means of FT-IR, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and elemental analysis. Also, some properties of CDA were determined. These results showed that CDA has better solubility, water-repellency, and resistance to acids and bases than raw cellulose, and these properties increase with the DS of CDA.

Enzymatic hydrolysis of cellulosic municipal wastewater treatment process residuals as feedstocks for the recovery of simple sugars

This study examined the hydrolysis of lignocellulose extracted from municipal wastewater treatment process residuals for the purpose of investigating low-cost feedstocks for ethanol production, while providing an alternative solid waste management strategy. Primary and thickened waste activated sludges and anaerobically digested biosolids underwent various pre-treatments to enhance subsequent enzymatic hydrolysis. Half of the pre-treated samples were dried and grinded, while the other half were used as is (wet). The wet primary sludge yielded the highest reducing sugar conversions. When wet primary sludge without pre-treatment was hydrolyzed at 40 degrees C and an enzyme loading of 800 U/g substrate, 31.1+/-2.7% was converted to reducing sugars in 24 h. This increased to 54.2+/-4.0% when HCl and KOH pre-treatments were applied. FTIR analyses were used to examine differences in the sludge compositions. These indicated that the cellulose content in the primary sludge was higher than that of the thickened waste activated sludge and biosolids, which was consistent with the higher reducing sugar yields observed in the primary sludge.

Improvement of alkali solubility of cellulose with enzymatic treatment

Cellulose was treated with different extracellular microbial enzymes. The treatment of cellulose with the enzymes can improve alkaline solubility. Both endoglucanase and crude cellulase decreased the average degrees of polymerization ([see text]) and improved the alkaline solubility of cellulose most efficiently. The composition of the enzyme, the type of cellulosic materials, pretreatment, and the treatment conditions are the key factors for its effective processing, using the enzymes to improve on alkaline solubility of cellulose. The improvement in the alkaline solubility is caused by the decrease in [see text] and hydrogen bond because of enzymatic hydrolysis.