Fundamental review of organosolv pretreatment and its challenges in emerging consolidated bioprocessing

Abstract

Lignocellulosic biomass is the most abundant renewable source of bioenergy. However, its intertwined structures prevent the embedded cellulose and hemicellulose from undergoing further chemical transformations. Organosolv pretreatment has been known to be effective in reducing the recalcitrance of lignocellulosic biomass. It possesses advantages in the recovery of components and the recovered components such as cellulose can be converted into bioproducts through consolidated bioprocessing (CBP). The main objective of this paper is to review recent developments in organosolv pretreatment, including a comparison of different organic solvents and their optimum operation conditions in terms of pretreatment performance and efficiency. Conventional solvents were also compared with several emerging solvents to discover more potential utilization of organosolv pretreatment. This paper also reviewed fundamental knowledge regarding organosolv pretreatment such as its mechanism, and the chemical and physical properties of the solvents, which are still rarely discussed in the literature due to a lack of conclusive information. The challenges and way forward for organosolv pretreatment were also analyzed in depth to consider the synergistic advantages after the integration of organosolv pretreatment into CBP. It is believed that, through more fundamental exploration and optimization work, organosolv pretreatment can play a vital role in determining the sustainability of CBP, to pave the way for more efficient bioprocessing in the future. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd

The Impact of Biomass and Acid Loading on Methanolysis during Two-Step Lignin-First Processing of Birchwood

“…), sometimes catalyzed by acids such as hydrochloric, sulfuric, oxalic, salicylic and Lewis acids. Compared with conventional kraft and sulfite pulping, organosolv pulping can overcome several drawbacks such as severe water and air pollution [13] and result in a lower sulfur content of the isolated lignin [14,15]. Lignin from organosolv pulping is mainly recovered as a solid product by addition of acidified water.…”

Biobased Resins Using Lignin and Glyoxal

“…A second class of biorefinery lignins are “organosolv lignins”, − which originate from organosolv pulping. − Although organosolv pulping was initially developed as an alternative for Kraft and sulfite pulping (early research dates back to the 1960s), today it mainly receives attention in the context of biorefineries . The technology has not yet reached commercial scale, but there are multiple examples of demonstrations at pilot scale (Figure ).…”

Single-Stage Fractionation of Vine Shoots Using Microwave Heating

“…Treatments performed in media containing water/1-butanol mixtures enable the selective separation of hemicelluloses in the aqueous phase and lignin in the organic one [19][20][21]24]. Additionally, the organic phase can be processed to recover the organic solvent to separate the lignin as a solid material for further valorization [37].…”

“…Efficient fractionation processes must provide an extensive lignin solubilization, yielding products that keep the structure and properties of the original polymer [23], and providing solids with enhanced cellulose contents. Additionally, the chemical treatment should be able to reduce the crystallinity of cellulose, increasing the available surface area, and enhancing the cellulose susceptibility to hydrolysis [24]. The enzymatic hydrolysis of cellulosic solids from fractionation leads to glucose solutions suitable as fermentation media for obtaining bioproducts such as ethanol or lactic acid [5,25].…”