Fungal delignification of lignocellulosic biomass improves the saccharification of cellulosics

The biological delignification of lignocellulosic feedstocks, Prosopis juliflora and Lantana camara was carried out with Pycnoporus cinnabarinus, a white rot fungus, at different scales under solid-state fermentation (SSF) and the fungal treated substrates were evaluated for their acid and enzymatic saccharification. The fungal fermentation at 10.0 g substrate level optimally delignified the P. juliflora by 11.89% and L. camara by 8.36%, and enriched their holocellulose content by 3.32 and 4.87%, respectively, after 15 days. The fungal delignification when scaled up from 10.0 g to 75.0, 200.0 and 500.0 g substrate level, the fungus degraded about 7.69–10.08% lignin in P. juliflora and 6.89–7.31% in L. camara, and eventually enhanced the holocellulose content by 2.90–3.97 and 4.25–4.61%, respectively. Furthermore, when the fungal fermented L. camara and P. juliflora was hydrolysed with dilute sulphuric acid, the sugar release was increased by 21.4-42.4% and the phenolics content in hydrolysate was decreased by 18.46 and 19.88%, as compared to the unfermented substrate acid hydrolysis, respectively. The reduction of phenolics in acid hydrolysates of fungal treated substrates decreased the amount of detoxifying material (activated charcoal) by 25.0–33.0% as compared to the amount required to reduce almost the same level of phenolics from unfermented substrate hydrolysates. Moreover, an increment of 21.1–25.1% sugar release was obtained when fungal treated substrates were enzymatically hydrolysed as compared to the hydrolysis of unfermented substrates. This study clearly shows that fungal delignification holds potential in utilizing plant residues for the production of sugars and biofuels.