Bioaugmentation with anaerobic fungi for biogas production from straw
Résumé
The digestive system of ruminant animals resembles the biogas fermenters with similar parameters like nearly neutral pH and a temperature of 37±2°C. In these natural biogas systems, anaerobic fungi play a major role in converting the lignocellulosic biomass into energy. In an anaerobic digestion process, the recalcitrance of lignocellulosic biomass poses a major hindrance to biogas production and hydrolysis of cellulose and hemicellulose is considered a rate-limiting step. However, anaerobic fungi are able to improve the hydrolysis by mechanically separating the plant fibers by their growing rhizoids and by producing a plethora of plant carbohydrate-hydrolyzing enzymes. In the present study, bioaugmentation with the anaerobic fungus Feramyces austinii (1 g fresh biomass/ 1.1 g VS of straw) was evaluated for biogas production from commercial straw which mainly composed of wheat straw. Our results demonstrated that Feramyces austinii was able to improve the hydrolysis rate by 2.2% and the overall methane production by 7.1% compared to control. Changes to lignocellulose such as lignin content reduction by anaerobic fungi were observed which provides holocellulose more susceptible to further bacterial degradation in anaerobic conditions. Further genotyping and enzymatic studies could help to understand Feramyces austinii’s ability to degrade lignin in anaerobic conditions. Research focusing on understanding the syntrophic relationships of Feramyces austinii with the microbial consortium present in the anaerobic digestates could help to further optimize the bioaugmentation protocol.
Origine : Fichiers produits par l'(les) auteur(s)
Licence : CC BY NC - Paternité - Pas d'utilisation commerciale
Licence : CC BY NC - Paternité - Pas d'utilisation commerciale