Recent advances in use of 4- coumarate coenzyme a ligase (4CL) as target gene for improving delignification of paper pulp in Leucaena leucocephala in Indian perspective: A review & case study

Abstract

Lignin provides support to plants by filling the gaps in cellulose, hemicellulose and pectin components but it is an undesired ingredient of pulp as it imparts black to brown colour to the pulp during paper making process. To remove lignin a lot of chemicals and bleaching agents are used which contribute to major fraction of environmental pollution as well as cost determination of paper making process. In India majorly Leucaena leucocephala is employed for obtaining pulp raw material owing to its properties suited for paper production such as vessel percentage, felting power, runkel ratio, tensile strength etc which is better than other commonly employed sources for paper pulp as raw material. In this review paper we focused on recent advances in the use of 4CL enzyme as target gene towards achieving model designer Leucaena leucocephala trees which can be a possible solution to this problem significantly minimizing the environmental pollution and cost of production. It is known from previous studies that better S/G lignin monomer ratio favours easy extractability of lignin from pulp. Different isoforms with different substrate specificities are known in different plants and knowledge of this differential substrate specificity in conjunction with regulation of expression of these isoforms can help in attaining desired S/G lignin monomer ratio. Thus, these model designer plants would be capable of naturally producing easily amenable lignin towards delignification by altering the S/G lignin ratio and can significantly cut the environmental pollution and cost determining factors for paper production.