Presence of aiiA homologue genes encoding for N-Acyl homoserine lactone-degrading enzyme in aflatoxin B 1 -decontaminating Bacillus strains with potential use as feed additives

GONZÁLEZ PEREYRA, M.L.; MARTÍNEZ, M.P.; CAVAGLIERI, L.R.

FOOD AND CHEMICAL TOXICOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2019 vol. 124 p. 316 - 323

0278-6915

Microbial degradation of aflatoxins (AFs) is an alternative to the use of mycotoxin binders. The lactone ring is a possible target for microbial enzymes and its cleavage reduces AFs toxicity. The aim of this study was to isolate and identify Bacillus strains able to degrade AFB 1 to less toxic metabolites and to identify aiiA genes encoding for N-acyl-homoserine lactone (AHL) lactonase to possibly correlate detoxification with the production of this enzyme. Eleven soilborne Bacillus strains were isolated and identified by MALDI-TOF MS. Ten cultures and eight cell free culture supernatants (CFCS) were able to significantly (P < 0.05) degrade 27.78?79.78% AFB 1 . Cell lysates were also able to degrade AFB 1 (P < 0.05). Exposure to 70 and 80 °C did not affect enzyme activity. Aflatoxin B 1 toxicity towards Artemia salina was reduced after degradation by each of the Bacillus strains. B. subtilis RC1B, B. cereus RC1C and B. mojavensis RC3B, amplified a fragment of 753 pb corresponding to the aiiA gene encoding for AHL lactonase. AFB 1 degradation by the strains tested was due to the extracellular and intracellular enzymes. If demonstrated to be safe, these could be used to detoxify AFB 1 in contaminated food or feed.