Effect of Dilute Acetic Acid Hydrolysis on Xylooligosaccharide Production and the Inhibitory Effect of Cellulolytic Enzyme Lignin from Poplar

Abstract

Acetic acid (AC) hydrolysis has been reported to prepare xylooligosaccharides (XOS) from poplar. However, the influence of AC hydrolysis on the lignin structure changes is not clear, which is important for the following enzymatic hydrolysis of poplar. Herein, AC was used to produce XOS, and cellulase adsorption on cellulolytic enzyme lignin (CEL) from AC-hydrolyzed poplar and its inhibitory effect on two commercial cellulase preparations were investigated. AC hydrolysis gave a XOS yield of 39.8% from poplar. After AC hydrolysis at 170 °C, the hydrophobicity and ζ-potential of CEL decreased to 2.3 L/g and 14.8 mV, respectively. The adsorption strength of CTec2 on CEL samples did not increase by AC hydrolysis, and the inhibitory effect of CEL on Celluclast 1.5L and β-glucosidase was observed, but not on CTec2. CEL samples improved the lytic polysaccharide monooxygenase (LPMO) activity of the enzymatic hydrolysis by CTec2. After CEL samples were added in enzymatic hydrolysis, the free filter paper activity of Celluclast 1.5L and β-G retained in the enzymatic hydrolysate decreased from 60.5 to 29.3−42.9%. The addition of CEL samples in enzymatic hydrolysis could not decrease the free filter paper activity of CTec2 retained in the enzymatic hydrolysate. In the enzymatic hydrolysis with CEL samples, higher glucose yields were obtained by CTec2 than those by Celluclast 1.5L and β-glucosidase. This work will help to understand the structure and inhibitory effects of AC-CELs and guide the development of AC hydrolysis for the production of XOS and monosaccharides from poplar.

Production of Prebiotic Xylooligosaccharides via Dilute Maleic Acid-Mediated Xylan Hydrolysis Using an RSM-Model-Based Optimization Strategy

“…At 170°C, XOS yields declined with increases in acid content and holding time owing to the accelerated conversion of XOS to xylose under these conditions such that treatment for 45 min with 0.1% MA at 170°C for 45 min resulted in an XOS yield of just 9.8%, whereas the xylose yield was as high as 80.1% ( Figure 1C ). These data suggest that overly harsh reaction conditions can result in the excessive breakdown of xylan, making them ill-suited to preparing XOS ( 31 ). It is, however, important to note that furfural yields remained low (<5 g/L) under even the harshest conditions (170°C/45 min/0.16%), owing to the dicarboxylic structural characteristics of MA, which mimic the active sites of natural enzymes and thereby stabilize xylose, slowing its degradation ( 32 ).…”

Furfural production from lignocellulosic biomass: one-step and two-step strategies and techno-economic evaluation

“…Currently, the largest producer of furfural is located in China (∼70% total production capacity). 35 Other countries, such as South Africa (20 000 t) and the Dominican Republic (32 000 t) contribute significant furfural production. 28 China and EU represent the largest and the second-largest markets with 55% and 15% of the global demand of furfural globally, respectively, which is expected to increase to 200 000 tons per year by 2030.…”

Evaluating the In Vitro and In Vivo Prebiotic Effects of Different Xylo-Oligosaccharides Obtained from Bamboo Shoots by Hydrothermal Pretreatment Combined with Endo-Xylanase Hydrolysis

“…It is well known that XOS can be acquired from xylan sourced from biomass through diverse approaches, such as mild acid hydrolysis or hydrothermal pretreatment [14,15]. In this study, the green, simple, and highly efficient technology of hydrothermal pretreatment was employed to obtain XOS from bamboo shoots (BS) at temperatures ranging from 150 • C to 190 • C. The aim was to determine the optimal pretreatment conditions that would yield the highest amount of XOS in the hydrolyzate (pretreatment solution).…”