Fungal diversity and keratinolytic activity of fungi from lignocellulosic composts with chicken feathers

The aim of the study was to evaluate the diversity and activity of the group of keratinophilic fungi in two composts with different quantitative and qualitative composition of lignocellulosic waste and chicken feathers. From compost I, with a lower feather proportion (3%), and from compost II with a higher feather proportion (13%), 114 and 116 keratinophilic strains, and 318 and 330 non-keratinophilic were isolated, respectively. Among keratinophilic fungi, the majority, i.e., 75% and 85% (compost II and I, respectively) were fungi from the Chrysosporium group. Apart from keratinophilic fungi, native keratin in composts was also inhabited by non-keratinophilic fungi. The dominant in composts keratinophilic species, Aphanoascus keratinophilus, was evaluated for native feather keratin biodegradation in pure cultures. Randomly selected 13 A. keratinophilus strains and, for comparison, one T. terrestre strain, degraded 44-83% of chicken feathers after 4 weeks, which classified these fungi as highly keratinolytic. These fungi synthesized proteo- and keratinolytic enzymes, which was accompanied by the release of soluble proteins and amino acids as well as N and S feather mineralization products. Composts with chicken feathers are a good source of highly keratinolytic fungi that can be used for biodegradtion of keratin waste.