Selective Ligninolysis of Wheat Straw and Wood Chips by the White-Rot Fungus Lentinula edodes and Its Influence on In Vitro Rumen Degradability

Author: mycolabadmin
2016-09-22
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Summary

This research investigated how treating agricultural waste materials (wheat straw and wood chips) with an edible mushroom fungus could make them more digestible as animal feed. The fungus breaks down tough lignin structures that normally prevent animals from accessing nutrients in plant materials. This natural treatment method could provide a more sustainable and environmentally friendly alternative to chemical treatments. Impacts on everyday life: • Provides a way to convert agricultural waste into valuable animal feed • Offers an environmentally friendly alternative to chemical treatments • Could reduce feed costs for farmers and livestock producers • Demonstrates potential applications of mushroom-producing fungi in biotechnology • Helps advance understanding of sustainable waste management practices

Background

Carbohydrates in plant cell walls can be an important source of nutrients for ruminants. However, these carbohydrates are bound to lignin, which can only be degraded under aerobic conditions by fungi and some bacteria, and cannot be broken down in the low oxygen environment of the rumen. Biological treatments using fungi that selectively degrade lignin may be more cost effective and less harmful compared to current chemical and physical pre-treatment methods.

Objective

To investigate the influence of lignin content and composition in the fungal treatment of lignocellulosic biomass to improve rumen degradability. The study compared wheat straw and wood chips, which differ in lignin composition, when treated with Lentinula edodes for varying time periods.

Results

L. edodes preferentially degraded lignin with limited cellulose degradation in both substrates, leaving them enriched in cellulose. Syringyl (S)-lignin units were preferentially degraded compared to guaiacyl (G)-lignin units, resulting in a decreased S/G ratio. Decreasing S/G ratio and selective lignin degradation were correlated with in vitro gas production. The fungal treatment increased the in vitro gas production of both substrates similarly, indicating lignin content and 3D-structure of cell walls influence rumen degradability more than lignin composition.

Conclusion

Changes in lignin composition were primarily a result of fungal degradation mechanisms rather than substrate properties. The main effects were selective S-unit over G-unit degradation and side chain degradation of lignin. Changes in lignin had similar effects on in vitro gas production for both substrates. Lignin content and cell wall 3D-structure had greater influence on rumen degradability than lignin composition changes.

Published in:Journal of Animal Science and Biotechnology,
Study Type:Laboratory Research,
Source: 10.1186/s40104-016-0110-z