Integration of Lignin Removal from Black Liquor and Biotransformation Process

Abstract

Industrial discharge has tremendously increased inorganic pollutants in water bodies all over the world. Paper and pulp mill effluent is included in one of the most pollution-generating discharges containing complex chemical compounds such as lignin. For clean and healthy water resources, the recovery of lignin from wastewater from the paper and pulp industry is of high importance. On the other hand, these pollutants can be carcinogenic, due to the chlorine lignin and chlorine phenols that are formed along the process. The main focus of this study on precipitation of lignin from the black liquor (influent) is one stage followed by dewatering/washing to improve purity of lignin. Lignin valorization is an essential process for an advanced, sustainable, and economical biomass-based industry. However, converting lignin into value-added products remains a challenge due to its heterogeneity and irregular structure. Complex nature of lignin depolymerized by aromatic-catabolizing organisms to create “biological funnels” that receive heterogeneous aromatic substrates and convert them to a few products. Microbes such as bacteria and fungi are involved in the lignin degradation. Degradation of lignin through white-rot fungi may be helpful for the biotechnical applications like biopulping, biobleaching and pulp mill effluents treatment, and soil bioremediation. White-rot fungi specifically P. chrysosporium, also known as model fungus, and Coriolus versicolor are potential degradation against recalcitrant chromophoric material in bleach plant effluents. The abundance and renewability of lignin potentially converted to valuable bioproduct may eventually replace existing technology on manufacturing industries.