Structural Characterization of Lignin-Carbohydrate Complexes (LCCs) and Their Biotransformation by Intestinal Microbiota In Vitro

Abstract

Lignin-carbohydrate complexes (LCCs) have recently emerged as natural products with pharmaceutical and nutraceutical potential. Here, we compared the structure of LCCs from ginkgo (GK, gymnosperms), wheat straw (WST, monocotyledons), and aspen white poplar (AW, dicotyledons). We also investigated the biotransformation of LCCs by intestinal microbiota in vitro. We found that human intestinal microbiota could use LCCs as a carbon source for growth, breaking resistant cross-linkages in LCCs to generate a plethora of short-chain fatty acids (SCFAs) and aromatic compounds with putative beneficial effects on human health. The yield of SCFAs reached 1837.8 ± 44.1 μmol/g using AW LCCs as a carbon source. The biomass of intestinal microbiota increased the fastest using GK LCCs. The greatest amounts of phenolics were present at 4 h in a WST LCCs fermentation system. Many phenolic acids with potential bioactivity were obtained after 24 h fermentation using each LCCs, such as ferulic acid.

In Vitro Fermentation of Beechwood Lignin–Carbohydrate Complexes Provides Evidence for Utilization by Gut Bacteria

“…Propionic acid can improve insulin sensitivity and lowers hepatic and plasma concentrations of fatty acids, and this therefore might prove to be an elusive effector of obesity and type II diabetes [ 34 ]. Zhang et al reported that LCC from different plants could be used as substrate for in vitro fermentation to increase the production of SCFAs [ 17 ]. This agrees with the results of the current study with BW-LCC as substrate.…”

“…In vitro studies revealed that lignin was an obstacle, as high-lignin content was more slowly digested by gut microbiota compared to low-lignin content [ 16 ]. Currently, in vitro fermentation of LCC from different plant sources has revealed that LCC could be utilized as a substrate to generate SCFAs and aromatic compounds and increase the growth rate of gut microbiota [ 17 ]. As of yet, it is not clear what effect LCC has on the composition of microbiota in the human gut.…”

Effective Biotransformation of Variety of Guaiacyl Lignin Monomers Into Vanillin by Bacillus pumilus

“…The supernatant was withdrawn periodically and used for the measurement of the concentration of total phenol and reducing sugar. The determination of total phenol and reducing sugar were conducted as previously described ( Yu et al, 2009 ; Zhang et al, 2021 ). Qualitative analysis of the depolymerized monomers in the supernatant was performed based on the GC/MS analysis described above.…”

Intestinal iron bio-accessibility changes by Lignin and the subsequent impact on cell metabolism and intestinal microbiome communities

“…16 In a human study, lignin was found to be undigested in both the small and large bowel 17 though, conversely, there is also evidence that lignin can be fermented by the intestinal microbiome to smaller molecular weight compounds in the large bowel. 18,19 Whether these lignin-derived metabolites or degradation components retain any iron chelating properties remains undetermined.…”