Elimination of Deoxynivalenol, Aflatoxin B1, and Zearalenone by Gram-Positive Microbes (<i>Firmicutes</i>)

Abstract

Mycotoxin contaminations in the feed and food chain are common. Either directly or indirectly, mycotoxins enter the human body through the consumption of food of plant and animal origin. Bacteria with a high mycotoxin elimination capability can reduce mycotoxin contamination in feed and food. Four Gram-positive endospore-forming bacteria (Bacillus thuringiensis AMK10/1, Lysinibacillus boronitolerans AMK9/1, Lysinibacillus fusiformis AMK10/2, and Rummeliibacillus suwonensis AMK9/2) were isolated from fermented forages and tested for their deoxynivalenol (DON), aflatoxin B1 (AFB1), and zearalenone (ZEA) elimination potentials. Notably, the contribution of bacterial cell wall fractions to the observed outstanding ZEA elimination rates was demonstrated; however, the ZEA elimination differed considerably within the tested group of Gram-positive bacteria. It is worth noting that the purified cell wall of L. boronitolerans AMK9/1, L. fusiformis AMK10/2 and B. thuringiensis AMK10/1 were highly efficient in eliminating ZEA and the teichoic acid fractions of B. thuringiensis AMK10/1, and L. fusiformis AMK10/2 could also be successfully used in ZEA binding. The ZEA elimination capacity of viable R. suwonensis AMK9/2 cells was outstanding (40%). Meanwhile, R. suwonensis AMK9/2 and L. boronitolerans AMK9/1 cells produced significant esterase activities, and ZEA elimination of the cell wall fractions of that species did not correlate with esterase activity. DON and AFB1 binding capabilities of the tested bacterial cells and their cell wall fractions were low, except for B. thuringiensis AMK10/1, where the observed high 64% AFB1 elimination could be linked to the surface layer (S-layer) fraction of the cell wall.

Keywords

• mycotoxins
• cell wall
• peptidoglycan
• S-layer
• zearalenone
• elimination