16 strains of Debaryomyces hansenii tested against Penicillium digitatum, a post harvest fungus, affecting citrus crops in Puerto Rico

Citrus crops contribute 11 million dollars to the Puerto Rican economy. Unfortunately, Penicillium spp. infects these crops causing a great economic loss. Debaryomyces hansenii, a marine halotolerant yeast, has the ability to produce a killer toxin which seems to be homologous to the KHR (killer toxin) gene of Saccharomyces cerevisiae whose activity in the reduction of the decay of citrus fruit caused by Penicillium spp. has been reported. Microbiology and molecular biology techniques have been used to characterize sixteen D. hansenii strains and isolate their killer toxin. Different assays of the killer toxin activity in vivo were realized to determine its potential as a biological control. Two strains, D. hansenii BCS 006 and YB-17914, were more efficient against Penicillium digitatum.