This study investigates Lactiplantibacillus plantarum fermentation
as a clean-label pretreatment to enhance the extraction and structural
characterization of β-glucans from Lentinula edodes (shiitake)
by-products. Shiitake residues are rich in β-(1→3)/(1→6)-glucans with
established immunomodulatory and anti-cancer potential; however, their
recovery is often limited by cell-wall rigidity and poor solubility. The
objective was to elucidate how microbial fermentation improves
accessibility to β-glucan-rich fractions and induces structural changes in
the extracted polysaccharides.
Dried shiitake by-products were fermented with L. plantarum under
controlled conditions (5% w/w substrate, 0.25% inoculum, 40 °C, 5 h) and
compared with unfermented controls. Following fermentation, polysaccharides
were extracted by mild alkaline treatment and ethanol precipitation.
Structural features were examined using HPAEC–PAD for monosaccharide
composition, HPSEC–MALLS–RI for molecular weight distribution, GC–MS for
glycosidic linkage analysis, and 1D/2D NMR spectroscopy for detailed
structural confirmation.
Fermentation increased polysaccharide extraction yield from 4.9% to 8.8%
(w/w) and total monosaccharide content from 68% to 93%. Glucose and
galactose were the predominant monosaccharides, indicating that
fermentation enhanced cell-wall disruption and solubilization of β-glucan
domains. HPSEC–MALLS revealed a broader molecular weight distribution in
fermented samples, suggesting improved recovery of structurally diverse
polysaccharides. GC–MS and NMR analyses confirmed a β-(1→3)-linked main
chain with β-(1→6)-linked side branches; fermented samples showed an
increased proportion of →6-linked residues, suggesting selective
debranching and enrichment of linear glucan segments through microbial
acidification and enzymatic modification.
This work demonstrates a sustainable bioprocess for valorizing mushroom
processing residues into high-quality polysaccharide ingredients. Enhanced
extraction of β-glucan fractions with defined linkage characteristics
provides a foundation for developing health-promoting, clean-label
ingredients. The findings contribute to understanding how controlled
fermentation can improve accessibility to complex fungal polysaccharides and
support their application as functional hydrocolloids and bio-based
components in the food industry.
The poster qualifies for “Best Poster Competition