Improving the perspective of raw eucalyptus kraft pulp for industrial applications through autochthonous bacterial mediated delignification

Abstract

Bacterial treatment to reduce lignin content, essential for upgrading the raw eucalyptus kraft pulp was evaluated. Chemical parameters of solid fraction (filtered pulp) and liquid fraction that can be correlated with the extent of pulp refining (in terms of delignification) were investigated by the action of Pseudomonas fluorescens NITDPY and Planococcus sp.TRC1 individually. In solid fraction, spectroscopic investigation showed the progressive reduction in phenol, lignin, color with successive bacterial treatment. Titrimetric process exhibited decrease of 37% and 32% in kappa number by Planococcus sp.TRC1 and P. fluorescens NITDPY, respectively. Liquid fraction showed the continuous release of lignin and its derived hydrophobic, phenolic and chromophoric components of non-cellulosic constituents. The evident improvements in the morphological features of bacterial delignified pulp were elucidated by SEM, XRD and SEM-EDXA. The analyses indicated reasonably efficient and economical route for recalcitrant lignin reduction, intended in broad range of industrial applications.