Related Experiment Video
Updated: May 10, 2026
Isolation and Screening from Soil Biodiversity for Fungi Involved in the Degradation of Recalcitrant Materials
Published on: May 16, 2022
Isolation of digested sludge-assimilating fungal strains and their potential applications
1Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan. kfujii@yamaguchi-u.ac.jp
Aims:
Digested sludge (DS) is a major waste product of anaerobic digestion of sewage sludge and is resistant to biodegradation. In this study, we isolated and characterized DS-assimilating fungi from soil.
Methods And Results:
We tried to isolate DS-assimilating strains by enrichment culture using DS as the nutrient source, but microbial growth was not observed in any culture. To eliminate the inhibitory effect of metals in DS on microbial growth, acid-treated DS was subsequently used for enrichment, and eight fungal strains were isolated from the subcultures. At least 10-30% reduction in sludge was observed after 1-week cultivation, and prolonged cultivation led to further sludge reduction. All isolates produced xylanase, chitinase and keratinase. Phylogenetic analysis revealed that the isolates were Penicillium, Fusarium, Chaetomium, Cunninghamella, Neosartorya and Umbelopsis. Some isolates were suggested novel species.
Conclusions:
To the best of our knowledge, our study is the first to report the isolation of DS-assimilating strains.
Significance And Impact Of The Study:
These isolates may be useful for commercial production of microbial enzymes using DS as the substrate. Because xylan, chitin and keratin in sludge-hyphae complexes are considered to be partially depolymerized, this material could also be utilized as a readily available fertilizer.
