Fig. 1: High-efficiency degradation of feather by SCUT-3 and application of fermented feather products in animal, plant, and microorganism cultures.

a Feather degradation rate of 1%, 10%, and 40% CFM by SCUT-3, presented as weight loss (red columns), and composition of amino acids, peptides, and insoluble proteins remaining undegraded in feather and bacteria of products (blue columns); n = 3/group. b, c 0 and 36 h SCUT-3 culture in 1% CFM, showing complete feather degradation. d, e 0 and 6 d SCUT-3 culture in 40% CFM. No feather plumage or shafts were visible in the sticky gruel after 6 days of feather fermentation. f Rice growth in control (left) and 50 mg amino acids added (from 10% SCUT-3 cultured CFM broth) (right) soil (50 g), showing the robust leaves and shorter roots with more root hairs. g Succulent growth in the control (left) and amino acids added (right) soil; n = 3/group, *P < 0.05. h Feed coefficients of full fish meal feed (45% fish meal, FM) and half fermented feather meal substitute feed (22.5% fish meal + 22.5% fermented feather meal, FM + FFM) after use for eight weeks in tilapia culture; n = 20/group, *P < 0.05. i Fresh weight of rice grown in control and supplemented soil; n = 6/group, *P < 0.05. j The effect of feather degradation products on microbial recombinant protein production; n = 3/group, *P < 0.05. The experimental group added 3 mg amino acids (from 10% SCUT-3 cultured CFM broth) to the control LB medium. Asterisks indicate significant differences in feed coefficient, fresh weight and recombinant protein production. P-values between groups were obtained by unpaired two-tailed Student’s t test. All data were presented as mean ± SD.