Biodegradation of bovine spongiform encephalopathy prions in compost

• Published in: Scientific reports Vol. 12; no. 1; pp. 22233 - 15
• Main Authors: Xu, Shanwei, Abeysekara, Sujeema, Dudas, Sandor, Czub, Stefanie, Staskevicius, Antanas, Mitchell, Gordon, Amoako, Kingsley K., McAllister, Tim A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23-12-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 631/326/421; 704/172/4081; Animal manures; Animal wastes; Animals; Animals, Genetically Modified; Bioassays; Biodegradation; Bovine spongiform encephalopathy; Brain - metabolism; Cattle; Composting; Composts; Encephalopathy, Bovine Spongiform - metabolism; Feathers; Feedlots; Food chains; Humanities and Social Sciences; Inactivation; Infectivity; Manure; Manures; Mice; Mice, Transgenic; Microorganisms; multidisciplinary; Prion protein; Prions - metabolism; Protein folding; Protein seeding; Proteolysis; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-022-26201-2

To reduce the transmission risk of bovine spongiform encephalopathy prions (PrP
BSE
), specified risk materials (SRM) that can harbour PrP
BSE
are prevented from entering the feed and food chains. As composting is one approach to disposing of SRM, we investigated the inactivation of PrP
BSE
in lab-scale composters over 28 days and in bin composters over 106–120 days. Lab-scale composting was conducted using 45 kg of feedlot manure with and without chicken feathers. Based on protein misfolding cyclic amplification (PMCA), after 28 days of composting, PrP
BSE
seeding activity was reduced by 3–4 log
10
with feathers and 3 log
10
without. Bin composters were constructed using ~ 2200 kg feedlot manure and repeated in 2017 and 2018. PMCA results showed that seeding activity of PrP
BSE
was reduced by 1–2 log
10
in the centre, but only by 1 log
10
in the bottom of bin composters. Subsequent assessment by transgenic (Tgbov XV) mouse bioassay confirmed a similar reduction in PrP
BSE
infectivity. Enrichment for proteolytic microorganisms through the addition of feathers to compost could enhance PrP
BSE
degradation. In addition to temperature, other factors including varying concentrations of PrP
BSE
and the nature of proteolytic microbial populations may be responsible for differential degradation of PrP
BSE
during composting.