Comments on the ochratoxin A degradation mechanism by Lysobacter sp. CW239 - Wei Wei et al. (2020)

This is a research comment on the ochratoxin A (OTA) degradation mechanism by Lysobacter sp. CW239 regarding the previous publication in Environmental Pollution (Wei et al., 2020). Three possible degradation mechanisms were discussed in the referred publication, but without definite evidences, it was not clear which one worked actually. Here, the gene cp4 deficient mutant CW239^Δcp4 was successfully constructed, and the carboxypeptidase CP4 role on OTA degradation in strain CW239 was validated in vivo. As a result, the mutant CW239^Δcp4 without gene cp4 showed less than 10% reduction of 24 hrs degradation ratio compared to wide-type strain CW239. After the gene cp4 complemented to CW239^Δcp4, the complementary strain (+)cp4 recovered the degradation ability to wide-type. The validation result indicated that the third degradation mechanism (i.e., OTA is degraded by joint action of multiple enzymes in CW239) proposed previous (Wei et al., 2020) was correct route for the degradation strain. This commentary was significant to the following studies on the pollutant detoxify strains with similar degradation characters between identified enzyme and the host strain.