Bioformulation of Yamadazyma mexicana LPa14 by electrospraying process: Anthracnose control and effect on postharvest quality of avocado fruit

Abstract

Anthracnose develops in the field and decreases the shelf life and the commercial value of avocado fruit. For its control from preharvest, a yeast bioformulation with high viability, intermediate release, and high efficiency must be applied. This work aimed to obtain a bioformulation of Yamadazyma mexicana LPa14 by electrospraying process and evaluate its effectiveness in biocontrol and the effect on avocado fruit quality. The survival percentage and release rates of 15 microencapsulated yeast treatments were evaluated. The antagonist activity of the optimal bioformulation was tested by comparing its effect with the commercial fungicide Bankit® Gold (Azoxystrobin). Finally, the population dynamics of the yeast in the epicarp and the avocado quality parameters were evaluated. The survival of microencapsulated Y. mexicana ranged between 40.5 and 99.2 %, and release rates from 0.11 to 0.42 (Log CFU/g)/h. The design maximized the yeast survival (95.2 %) and allowed an intermediate release rate (0.32 (Log CFU/g)/h). The bioformulation was more effective in avocado fruits at 6 °C for 10 days and ripening at 25 °C for 5 days, reducing the severity and incidence of anthracnose by 88.9 and 80 %, respectively. The controlled release of the yeast in the epicarp at 6 and 25 °C ensured an effective concentration (7.1 Log CFU/fruit) until the 15th day. Y. mexicana did not alter the physicochemical quality of the fruit. In conclusion, an effective yeast bioformulation was obtained. Microencapsulated Y. mexicana can replace synthetic fungicides and can be used as an ecological alternative for anthracnose control. The yeast bioformulation may preserve the avocado fruit quality during storage. Furthermore, this study offers new insights for the future development of encapsulated bioformulations for pathogen control.