Affiliation:
1. Institute of Food Science and Nutrition, ETH Zurich, Schmelzbergstrasse 7, 8092 Zurich, Switzerland
Abstract
ABSTRACT
Immobilization and magnetic separation for specific enrichment of microbial cells, such as the pathogen
Listeria monocytogenes
, depends on the availability of suitable affinity molecules. We report here a novel concept for the immobilization and separation of bacterial cells by replacing antibodies with cell wall-binding domains (CBDs) of bacteriophage-encoded peptidoglycan hydrolases (endolysins). These polypeptide modules very specifically recognize and bind to ligands on the gram-positive cell wall with high affinity. With paramagnetic beads coated with recombinant
Listeria
phage endolysin-derived CBD molecules, more than 90% of the viable
L. monocytogenes
cells could be immobilized and recovered from diluted suspensions within 20 to 40 min. Recovery rates were similar for different species and serovars of
Listeria
and were not affected by the presence of other microorganisms. The CBD-based magnetic separation (CBD-MS) procedure was evaluated for capture and detection of
L. monocytogenes
from artificially and naturally contaminated food samples. The CBD separation method was shown to be superior to the established standard procedures; it required less time (48 h versus 96 h) and was the more sensitive method. Furthermore, the generalizability of the CBD-MS approach was demonstrated by using specific phage-encoded CBDs specifically recognizing
Bacillus cereus
and
Clostridium perfringens
cells, respectively. Altogether, CBD polypeptides represent novel and innovative tools for the binding and capture of bacterial cells, with many possible applications in microbiology and diagnostics.
Publisher
American Society for Microbiology
Subject
Ecology,Applied Microbiology and Biotechnology,Food Science,Biotechnology
Cited by
149 articles.
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