Yeast dynamics during the fermentation of brined green olives treated in the field with kaolin and Bordeaux mixture to control the olive fruit fly

The yeast microbiota associated with naturally fermented and inoculated green table olives, differentlytreated in the field with non-conventional repellent and antiovipositional products in the control of Bactroceraoleae, was analysed using a combination of culture-dependent and -independent molecular fingerprinting.The routine yeast isolation gave rise to 118 strains, whose identification was performed by PCR-RFLP of theinternal transcribed spacer (ITS) regions. Total DNA was extracted directly from the brine throughoutfermentation by means of an experimental protocol that included the removal of Taq polymerase inhibitors.Denaturing Gradient Gel Electrophoresis (DGGE) of 26S rRNA gene PCR amplicons highlighted the yeastcommunity. Comparison of both culture-dependent and independent methods indicated that the yeastspecies Saccharomyces cerevisiae, Wickerhamomyces anomalus, Candida diddensiae and Issatchenkia orientaliswere dominant during fermentation despite the addition of the Lactobacillus plantarum starter used in brining.The resultant isolated species were unaffected by treatments in field, except for C. diddensiae whose growthwas delayed by kaolin.