Surfactants, Biosurfactants, and Non-Catalytic Proteins as Key Molecules to Enhance Enzymatic Hydrolysis of Lignocellulosic Biomass

Abstract

Lignocellulosic biomass (LCB) has remained a latent alternative resource to be the main substitute for oil and its derivatives in a biorefinery concept. However, its complex structure and the underdeveloped technologies for its large-scale processing keep it in a state of constant study trying to establish a consolidated process. In intensive processes, enzymes have been shown to be important molecules for the fractionation and conversion of LCB into biofuels and high-value-added molecules. However, operational challenges must be overcome before enzyme technology can be the main resource for obtaining second-generation sugars. The use of additives is shown to be a suitable strategy to improve the saccharification process. This review describes the mechanisms, roles, and effects of using additives, such as surfactants, biosurfactants, and non-catalytic proteins, separately and integrated into the enzymatic hydrolysis process of lignocellulosic biomass. In doing so, it provides a technical background in which operational biomass processing hurdles such as solids and enzymatic loadings, pretreatment burdens, and the unproductive adsorption phenomenon can be addressed.

Synthesis of NMN by cascade catalysis of intracellular multiple enzymes

“…In whole cell biocatalysis, in addition to external environmental factors, the barrier functions of the cell wall and membrane affect the catalytic efficiency. 18 Therefore, we selected four surfactants to improve the production efficiency of NMN. As depicted in Fig.…”

Lipopeptide Biosurfactants Enhanced Biohydrogen Evolution from Lignocellulose Biomass and Shaped the Microbial Community and Diversity

“…To address this intricate structural obstacle, a variety of physical, physicochemical, and biological pretreatment methods have been used, significantly contributing to the conversion of lignocellulosic biomass [7]. However, some obstacles persist in the process of enzymatic hydrolysis of lignocellulosic biomass, including those related to nonproductive binding, limited total solid loading, and reduced enzyme activity [7].…”

“…To address this intricate structural obstacle, a variety of physical, physicochemical, and biological pretreatment methods have been used, significantly contributing to the conversion of lignocellulosic biomass [7]. However, some obstacles persist in the process of enzymatic hydrolysis of lignocellulosic biomass, including those related to nonproductive binding, limited total solid loading, and reduced enzyme activity [7]. In order to maximize the effectiveness of the enzymatic hydrolysis of vegetal biomass, it has been suggested that surfactant molecules can lower surface tension and alter the structure of plant biomass and can be employed as effective additives [7].…”

“…However, some obstacles persist in the process of enzymatic hydrolysis of lignocellulosic biomass, including those related to nonproductive binding, limited total solid loading, and reduced enzyme activity [7]. In order to maximize the effectiveness of the enzymatic hydrolysis of vegetal biomass, it has been suggested that surfactant molecules can lower surface tension and alter the structure of plant biomass and can be employed as effective additives [7]. In a study conducted by Chen et al, the use of Tween 20 resulted in enhanced efficacy of the enzymatic hydrolysis process applied to acid-pretreated wheat straw.…”

“…Although synthetic surfactants are widely used, it is important to note that these compounds are nonbiodegradable and have been identified as environmentally harmful [9]. The use of microbial-derived biological surfactants provides a more sustainable scenario due to their biodegradability, biocompatibility, and low toxicity properties [7,10]. Hosny and El-Sheshtawy studied to assess the capacity of cellulase-producing bacteria to hydrolyze municipal garbage, with the inclusion of a bacterial lipopeptide (surfactin) biosurfactant as an addition [11].…”