The Antimicrobial Properties of Technical Lignins and Their Derivatives-A Review

Abstract

Lignin represents one of the most abundant plant-derived polymers. It is mostly present in the cell wall, and its primary role is to provide mechanical support to the plant. Chemical processes during wood-pulping yield diverse technical lignins with distinct characteristics. Due to their complex and variable nature, technical lignins are often undervalued and are mainly used as burning fuel in mills. However, various technical lignins have been shown to possess antimicrobial properties. Consequently, there is an increasing interest in understanding the properties and conditions that underlie their antimicrobial characteristics and how we can utilize them for practical applications. This review, for the first time, comprehensively summarized the antimicrobial activities of technical lignins and their potential antimicrobial applications.

Keywords: antimicrobial; applications; technical lignins.

Figure 1

Primary lignin monolignols.

Figure 2

Antimicrobial mechanisms of technical lignins and their derivatives. (A) Lignin polyphenols induce oxidative stress within bacterial cells by generating reactive oxygen species (ROS), thereby causing cellular damage [6,28]; (B) lignin nanoparticles penetrate bacterial cell walls, disrupting membranes and altering permeability, leading to cell lysis [28,29]; (C) the generation of ROS reduces intracellular pH and depletes ATP [28]; (D) lignin particles bind with cytoplasmic components, potentially altering or inhibiting the expression of key metabolic proteins [28,29]; (E) certain lignin types possess strong surfactant properties that interact with lipids and proteins, adversely affecting fungal growth and viability [30,31]; (F) lignin particles interfere with viral entry by interacting with virus envelopes [8].