Biodegradation of Prions in Compost

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• 作者：Shanwei Xu ; Tim Reuter ; Brandon H. Gilroyed ; Gordon B. Mitchell ; Luke M. Price ; Sandor Dudas ; Shannon L. Braithwaite ; Catherine Graham ; Stefanie Czub ; Jerry J. Leonard ; Aru Balachandran ; Norman F. Neumann ; Miodrag Belosevic ; Tim A. McAllister
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：June 17, 2014
• 年：2014
• 卷：48
• 期：12
• 页码：6909-6918
• 全文大小：413K
• 年卷期：v.48,no.12(June 17, 2014)
• ISSN：1520-5851

文摘

Composting may serve as a practical and economical means of disposing of specified risk materials (SRM) or animal mortalities potentially infected with prion diseases (transmissible spongiform encephalopathies, TSE). Our study investigated the degradation of prions associated with scrapie (PrP^263K), chronic waste disease (PrP^CWD), and bovine spongiform encephalopathy (PrP^BSE) in lab-scale composters and PrP^263K in field-scale compost piles. Western blotting (WB) indicated that PrP^263K, PrP^CWD, and PrP^BSE were reduced by at least 2 log₁₀, 1鈥? log₁₀, and 1 log₁₀ after 28 days of lab-scale composting, respectively. Further analysis using protein misfolding cyclic amplification (PMCA) confirmed a reduction of 2 log₁₀ in PrP^263K and 3 log₁₀ in PrP^CWD. Enrichment for proteolytic microorganisms through the addition of feather keratin to compost enhanced degradation of PrP^263K and PrP^CWD. For field-scale composting, stainless steel beads coated with PrP^263K were exposed to compost conditions and removed periodically for bioassays in Syrian hamsters. After 230 days of composting, only one in five hamsters succumbed to TSE disease, suggesting at least a 4.8 log₁₀ reduction in PrP^263K infectivity. Our findings show that composting reduces PrP^TSE, resulting in one 50% infectious dose (ID₅₀) remaining in every 5600 kg of final compost for land application. With these considerations, composting may be a viable method for SRM disposal.