Since pieces of bioplastic C disintegrated within the first 14 days
of incubation, we could not obtain direct spectra of this composted
bioplastic after 60 days. However, the spectral contribution of the
composted bioplastic C (Fig. 2) could be determined by spectral
subtraction using the respective spectra of the bioplastic C/inoculum
mixture and the inoculum without added bioplastic. NIR spectroscopy
results revealed that, in contrast to other bioplastic
components, PFF was not degraded during composting. Prior to
composting the spectra of type C bioplastic contained peaks similar to those seen in the spectra of glycerol and urea. However, the spectra
of composted type C bioplastic closely matched that of pure
poultry feather fiber. Due to its resistance to proteolytic enzymes,
feather keratin is not easily biodegradable