Background: This study evaluates the detoxification potential of Lacticaseibacillus rhamnosus B1, isolated from artisanal ewe milk butter in Laghouat, Algeria, against ochratoxin A (OTA) through both degradation and adsorption mechanisms. Methods: API 50 CHL carbohydrate fermentation profiling and 16S rRNA gene sequencing were used to identify the strain studied in this work. HPLC with C18 reversed-phase column was used to analyze OTA. Result: The isolate was confirmed as Lacticaseibacillus rhamnosus B1 (GenBank accession number PV577804). In degradation assays, L. rhamnosus B1 reduced OTA by 25% after 7 days at 37°C in MRS broth (1 µg/ml OTA), producing 0.250 µg/ml of the less toxic ochratoxin alpha (OTα), as confirmed by HPLC analysis (λexc = 333 nm, λem = 460 nm). Adsorption experiments revealed that dead cells adsorbed 80% of OTA (0.800 µg/ml in pellet) at pH 3.5 after 1 hour, while live cells achieved a 50% adsorption rate (0.500 µg/ml in pellet) under identical conditions. HPLC chromatograms highlighted OTA peaks at ~6.9 minutes, with minor peaks at ~2 minutes, suggesting the presence of impurities. The stability of OTA binding to bacterial biomass was found to be pH-dependent, with acidic conditions enhancing adsorption, possibly due to interactions with cell wall components such as peptidoglycans. These findings demonstrate the dual role of L. rhamnosus B1 in OTA detoxification and support its potential application in mycotoxin mitigation strategies for food safety.
Krantar et al. (Tue,) studied this question.