Application of microbial enzymes in dissolving pulp production

Abstract

The uprising demand in dissolving pulp, a special chemical pulp, during the last decade has fascinated the researchers to develop a modern biotechnology which could either improve its existing processes or facilitate novel processes of production in eco-friendly manner. These include the use of different microbial enzymes or the microorganisms themselves in various bioprocesses such as biopulping and/or biobleaching of sulphite pulp or bioconversion of kraft pulp to dissolving pulp. The hydrolytic enzymes specifically xylanases and cellulases have been used as the process tools rendering the benefit of eco-friendly and economic bioprocess. Special emphasis is paid to convert kraft pulp, originating from both wood and nonwood, into dissolving pulp by using xylanases and cellulases to selectively reduce hemicelluloses and improve pulp reactivity, respectively. The viscose process being a major consumer of dissolving pulp has drawn more attention. Extensive research work has been conducted to achieve high pulp reactivity as well as accessibility towards solvent and reagent for reducing the carbon disulphide (CS2) consumption in viscose process. Here, the various characteristic properties of dissolving pulp and its end use with various processes, including existing and novel, for its production are reviewed. Microbial enzymes, namely, xylanases and cellulases, for their immense potential as process tools are briefly discussed along with their mode of action.