Integrated Approach for Bioethanol and Paper Production using Populus deltoides Wood Biomass: An Experimental Study

Abstract

Lignocellulosic materials contain two major sugar macromolecules, cellulose and hemicellulose, and polyphenolic lignin. During pulping, lignin and hemicellulose are broken down into smaller molecules such as organic acids, and removed in the black liquor, leaving cellulose fibers for papermaking. Lignocellulose consists of approximately 28–35% hemicelluloses, which are lost during the pulping process in black liquor and are an important source of sugars that can be used to produce bioethanol as a liquid fuel. The hemicellulosic sugars from the Populus deltoides (poplar) lignocellulosic biomass were partially extracted keeping in mind that it does not affect the properties of paper beyond acceptable limits, further converting these extracted sugars by fermentation to bioethanol, followed by pulping the residual biomass and papermaking and determining pulping and papermaking properties. With the increasing demand for lignocellulosic biomass by various industries, an integrated biorefinery approach for maximum utilization of its chemical components with minimum degradation is necessary in the future. The maximum bioethanol yield was found to be 3.58 g/L. On manufactured paper sheets, the mechanical properties tensile index and tear index of pre-extracted biomass were observed as 19.23 Nm/g and 3.5 mNm2/g and slightly lower against the control 21.34 Nm/g and 4.0 mNm2/g. The main objective of the present study is to recover reducing sugars before the pulping process for bioethanol production and to further utilize the remaining residue for papermaking without disturbing its fiber integrity.