Conversion of Lignocellulosic Biomass to Reducing Sugars in High Pressure and Supercritical Fluids: Greener Alternative for Biorefining of Renewables

Abstract

Supercritical fluids offer great potential to be employed in lignocellulosic biomass (LCB) fractionation in biorefinery. Supercritical carbon dioxide and water are greener alternatives compared with conventional reagents and have been investigated for the pretreatment and hydrolysis of lignocellulosic biomass. This review is focused on examining the fundamentals that govern the function of supercritical fluids in the pretreatment stage, as well as in the main hydrolysis reaction. Sub/supercritical carbon dioxide is used in pretreatment and sub/supercritical water has been the solvent of choice in hydrolysis of LCB. Significant research has gone into understanding the effect of process parameters such as temperature, pressure, cosolvent, and use of external catalyst on the sugar yield in biorefining of the LCB in supercritical fluids. It is shown that processes with reduced environmental impact and energy consumption can significantly enhance biorefining of LCB at commercial scale. Enzymatic hydrolysis of LCB in supercritical carbon dioxide is a promising approach that can accommodate mild reaction conditions. Developing an understanding of the performance of enzymes in high pressure systems and designing carriers for enzyme immobilization and further recycling is expected to enable one pot pretreatment and hydrolysis and is an important milestone in processing renewable resources for deriving biofuel and value‐added chemicals.

Unraveling The Impact of Isomerism on Enzymatic Polymerization of Furanic Polyesters

“…They have been known to significantly contribute to reducing reliance on fossil-based materials while minimizing their adverse impact on the environment. [2][3][4] A well-known biobased building block, 2,5-furandicarboxylic acid (2,5-FDCA) which could be derived from 5hydroxymethylfurfural (HMF) obtained from lignocellulosic biomass, [5][6][7] has been the subject of numerous studies. One of its polymers, poly(ethylene 2,5-furanoate), shares many similarities with its petrol-based counterpart, poly(ethylene terephthalate) (PET).…”

“…A well‐known biobased building block, 2,5‐furandicarboxylic acid (2,5‐FDCA) which could be derived from 5‐hydroxymethylfurfural (HMF) obtained from lignocellulosic biomass, [ 5–7 ] has been the subject of numerous studies. One of its polymers, poly(ethylene 2,5‐furanoate), shares many similarities with its petrol‐based counterpart, poly(ethylene terephthalate) (PET).…”

Recovery of Nitrogen from Low-Cost Plant Feedstocks Used for Bioenergy: A Review of Availability and Process Order

“…In the last two decades, different lignocellulosic biorefinery approaches have been proposed based on different pretreatment strategies and fractionation of pretreated biomass into multiple streams (e.g., lignin, cellulose, hemicellulose, and their hydrolysates) for the generation of value-added products at different stages. − Biochemical processing approaches based on lignocellulosic-derived sugars are favored over other biorefinery models due to milder processing conditions and overall sustainability. , The majority of research on feedstocks for biofuel and biobased chemicals has focused on carbohydrates, lignin, and lipids (the CHO-containing fractions). , Cellulose-based biorefinery concepts have been developed. , Proteins and other N-containing fractions of biomass have received relatively little attention. , …”

“…12−14 Biochemical processing approaches based on lignocellulosic-derived sugars are favored over other biorefinery models due to milder processing conditions and overall sustainability. 15,16 The majority of research on feedstocks for biofuel and biobased chemicals has focused on carbohydrates, lignin, and lipids (the CHO-containing fractions). 17,18 Cellulose-based biorefinery concepts have been developed.…”