Characterization of Volatiles Organics compounds of two biocontrol agents Pichia anomala strain K and Candida oelophila strain O

Among the large diversity of microbial secondary metabolites, low molecular-weight volatile organic compounds (VOCs) have received growing attention in the past decade. Many fungal species and yeast have the ability to produce low concentrations of antifungal substances. This would open the way as alternative method to control microbial decays via biofumigation, as it does not require physical contact with the product or commodity to be treated.
The yeasts antagonists, Pichia anomala strain K, and Candida oelophila Strain O were among the most studied yeast antagonists in Phytopathology Lab. And well known as potential biocontrol agent to manage post-harvest disease of apples. Beyond their primary mode of action, which rely on nutrient competition and glucanase production, the ability of these yeasts to produce volatiles organic compounds was investigated. The VOCs were assayed with a double petri dish test against P. expansum and B. cinerea. Results showed that the VOCs generated by the antagonists inhibited significantly pathogen growth. In parallel an in vivo trial was carried out to assess the ability of produced VOCs to inhibit pathogen growth in in vivo conditions. The characterization of produced volatiles was assessed using solid-phase microextraction (SPME)–gas chromatographic technique.
The results showed a three common produced compounds: the 1-Propanol, 2-methyl, Isoamylalcohol and the phenethyl alcohol. The pure standard compounds were tested individually to assess their ability in pathogen growth inhibition.