Synergistic Improvement of Carbohydrate and Lignin Processability by Biomimicking Biomass Processing

Abstract

The sustainability and economic feasibility of modern biorefinery depend on the efficient processing of both carbohydrate and lignin fractions for value-added products. By mimicking the biomass degradation process in white-rote fungi, a tailored two-step fractionation process was developed to maximize the sugar release from switchgrass biomass and to optimize the lignin processability for bioconversion. Biomimicking biomass processing using Formic Acid: Fenton: Organosolv (F2O) and achieved high processability for both carbohydrate and lignin. Specifically, switchgrass pretreated by the F2O process had 99.6% of the theoretical yield for glucose release. The fractionated lignin was also readily processable by fermentation via Rhodococcus opacus PD630 with a lipid yield of 1.16 g/L. Scanning electron microscope analysis confirmed the fragmentation of switchgrass fiber and the cell wall deconstruction by the F2O process. 2D-HSQC NMR further revealed the cleavage of aryl ether linkages (β-O-4) in lignin components. These results revealed the mechanisms for efficient sugar release and lignin bioconversion. The F2O process demonstrated effective mimicking of natural biomass utilization system and paved a new path for improving the lignin and carbohydrate processability in next generation lignocellulosic biorefinery.

Bioconversion of Agave Bagasse Lignin to Medium-Chain-Length Polyhydroxyalkanoates by Pseudomonas putida

“…Briefly, GPC analyses were performed in acetylated lignin samples by an Agilent GPC SECurity 1200 system using a polystyrene standard and conditions reported elsewhere. 31 In regard to the NMR analyses, a Bruker Ascend 500 MHz spectrometer was used to perform both 2D 1 H− 13 C HSQC and 31 P NMR as previously reported. 32,33 ■ RESULTS AND DISCUSSION Chemical Composition of ATB Lignin and Its Potential for PHA Production.…”

“…Additionally, dried samples of lignin before and after fermentation were analyzed by gel permeation chromatography (GPC) and NMR to determine the molecular weight as well as the interunit linkages, aromatic regions, and lignin subunits. Briefly, GPC analyses were performed in acetylated lignin samples by an Agilent GPC SECurity 1200 system using a polystyrene standard and conditions reported elsewhere . In regard to the NMR analyses, a Bruker Ascend 500 MHz spectrometer was used to perform both 2D 1 H– 13 C HSQC and 31 P NMR as previously reported. , …”

“…Further information on the changes of lignin structure during pretreatment and fermentation was acquired by quantitative 31 P NMR analysis to determine the changes on hydroxyl groups. Table 6 shows that the contents of phenolic hydroxyl groups are increased, while a decrease of the aliphatic OH group content is observed after pretreatment.…”

“…Quantification of Different Hydroxyl Group Contents in Lignin Samples before and after Fermentation Determined by31 P NMR Spectra a…”

Transcriptomic and metabolomic analysis reveals the influence of carbohydrates on lignin degradation mediated by Bacillus amyloliquefaciens

“…On the other hand, as reported previously, the process of lignin degradation mediated by bacteria requires extensive reducing power and energy, which is mainly generated by the glycolysis of glucose (hexose), to deal with the decomposition of polymeric structures and corresponding oxidative stress during aromatic compound catabolism (Li et al, 2019). Therefore, several studies have evaluated the co-fermentation of lignin with glucose, with the findings indicating that the addition of glucose can promote the process of lignin degradation (Linger et al, 2014;Salvachúa et al, 2015Salvachúa et al, , 2020Liu et al, 2019b). However, to the best of our knowledge, no published studies have investigated the detailed mechanism, underlying the effect of carbohydrates on lignin degradation by bacteria.…”