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Research article - Peer-reviewed, 2018

Screening of intact yeasts and cell extracts to reduce Scrapie prions during biotransformation of food waste

Huyben, David; Boqvist, Sofia; Passoth, Volkmar; Renstrom, Lena; Bengtsson, Ulrika Allard; Andreoletti, Olivier; Kiessling, Anders; Lundh, Torbjorn; Vagsholm, Ivar

Abstract

Yeasts can be used to convert organic food wastes to protein-rich animal feed in order to recapture nutrients. However, the reuse of animal-derived waste poses a risk for the transmission of infectious prions that can cause neurodegeneration and fatality in humans and animals. The aim of this study was to investigate the ability of yeasts to reduce prion activity during the biotransformation of waste substrates-thereby becoming a biosafety hurdle in such a circular food system. During pre-screening, 30 yeast isolates were spiked with Classical Scrapie prions and incubated for 72 h in casein substrate, as a waste substitute. Based on reduced Scrapie seeding activity, waste biotransformation and protease activities, intact cells and cell extracts of 10 yeasts were further tested. Prion analysis showed that five yeast species reduced Scrapie seeding activity by approximately 1 log10 or 90%. Cryptococcus laurentii showed the most potential to reduce prion activity since both intact and extracted cells reduced Scrapie by 1 log10 and achieved the highest protease activity. These results show that select forms of yeast can act as a prion hurdle during the biotransformation of waste. However, the limited ability of yeasts to reduce prion activity warrants caution as a sole barrier to transmission as higher log reductions are needed before using waste-cultured yeast in circular food systems.

Keywords

Food waste; Prions; Protease; Yeast

Published in

Acta Veterinaria Scandinavica
2018, volume: 60, article number: 9

Authors' information

Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Swedish University of Agricultural Sciences, Department of Molecular Sciences
Renström, Lena
National Veterinary Institute (SVA)
Allard Bengtsson, Ulrika
National Veterinary Institute (SVA)
Andréoletti, Olivier
École Nationale Vétérinaire de Toulouse
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management
Swedish University of Agricultural Sciences, Department of Animal Nutrition and Management

Associated SLU-program

Food Waste

Sustainable Development Goals

SDG12 Ensure sustainable consumption and production patterns

UKÄ Subject classification

Food Science
Cell and Molecular Biology

Publication Identifiers

DOI: https://doi.org/10.1186/s13028-018-0363-y

URI (permanent link to this page)

https://res.slu.se/id/publ/93796