NC State
  • Researchpp 234-246Soni, R., Nazir, A., Chadha, B. S., and Saini, H. S. (2008). "Novel sources of fungal cellulases for efficient deinking of composite paper waste," BioRes. 3(1), 234-246.AbstractPDF
    Twenty thermophilic/thermotolerant fungal strains were isolated from compositing soils and screened for production of different enzymes (Endoglucanases, β-glucosidase, Fpase and xylanases) to assess their deinking efficiency. Three isolates, Aspergillus sp. AMA, Aspergillus terreus AN1,and Myceliophthora fergusii T4I, identified on the basis of morphological and sequencing of amplified ITS1-5.8S-ITS2 rDNA region, showed significant deinking of composite waste paper (70% magazine and 30% Xerox copier/ laser print paper waste) as well as improved properties (brightness, tensile strength, tear index) of recycled paper sheets. The chosen strains Aspergillus sp. AMA, Aspergillus terreus AN1and Myceliophthora fergusii T4I, showed 53, 52.7, and 40.32% deinking with increase in brightness by 4.32, 3.56, and 3.01 % ISO, respectively. These cultures were found to produce multiple endoglucanases and were characterized to lack a cellulose binding module (CBD), which may be responsible for their better deinking efficiency.
  • Researchpp 247-254Chen, Y., Liu, Y.-F., and Tan, H.-M. (2008). "Preparation of macroporous cellulose-based superabsorbent polymer through the precipitation method," BioRes. 3(1), 247-254.AbstractPDF
    Superabsorbent polymer was prepared by graft polymerization of acrylic acid onto the chain of carboxymethyl cellulose. This superabsorbent polymer was further treated by the solvent precipitation method. We found that the water absorption rate of the treated polymer was greatly increased and the microstructure of the treated polymer was changed from close-grained structures to loose macropores. The swelling processes of the polymers before and after modification fit first-order dynamic processes. The amount of the residual acrylic acid was detected through high performance liquid chromatography (HPLC) with aqueous solution of MOPS of 0.02mol/L (pH=5.70) as the mobile phase. It was found that the amount of the residual acrylic acid decreased from 83.8×10-4 % to 6.7×10-4 % after treatments.
  • Reviewpp 255-269Gonzalez, R. W., Saloni, D., Dasmohapatra, S., and Cubbage, F. (2008). "South America: Industrial roundwood supply potential," BioRes. 3(1), 255-269.AbstractPDF
    South America has substantial potential to expand its forest plantations and raw material supply. From 1997 to 2005, South America had a high annual growth rate in the production of industrial roundwood, with Brazil and Chile being the most important countries. In the same period, Asia had the only negative regional production growth rate in the world, and China became the largest round wood importer in the world. This paper summarizes the status of production, consumption, imports, and exports of industrial roundwood and forest products in South America. Produc-tion and exports from South America have continually increased at annual growth rates exceeding the forestry sector in general and the U.S. in particular. Based on timber growing investments to date, a strong timber production and forest products manufacturing sector has developed in the Southern Cone countries of Chile, Brazil, Argentina, and Uruguay, and is increasing in other countries in Latin America. There will be continued opportunities for forest plantations and new manufacturing facilities throughout South America, tempered somewhat by perceived country financial and political risks. These opportunities will allow South America to increase its share of world production and increase imports to North America and to Asia. PDF
  • Reviewpp 270-294Hu, G., Heitmann, J. A., and Rojas, O. J. (2008). "Feedstock pretreatment strategies for producing ethanol from wood, bark, and forest residues," BioRes. (3(1), 270-294.AbstractPDF
    Energy and environmental issues are among the major concerns facing the global community today. Transportation fuel represents a large proportion of energy consumption, not only in the US, but also world-wide. As fossil fuel is being depleted, new substitutes are needed to provide energy. Ethanol, which has been produced mainly from the fermentation of corn starch in the US, has been regarded as one of the main liquid transportation fuels that can take the place of fossil fuel. However, limitations in the supply of starch are creating a need for different substrates. Forest biomass is believed to be one of the most abundant sources of sugars, although much research has been reported on herbaceous grass, agricultural residue, and municipal waste. The use of biomass sugars entails pretreatment to disrupt the lignin-carbohydrate complex and expose carbohydrates to enzymes. This paper reviews pretreatment technologies from the perspective of their potential use with wood, bark, and forest residues. Acetic acid catalysis is suggested for the first time to be used in steam explosion pretreatment. Its pretreat-ment economics, as well as that for ammonia fiber explosion pretreatment, is estimated. This analysis suggests that both are promising techniques worthy of further exploration or optimization for commercialization.