Biocontrol Efficacy of the Vishniacozyma Victoriae in Semi-Commercial Assays for the Control of Postharvest Fungal Diseases of Organic Pears.

Vishniacozyma victoriae NPCC 1263 was selected for this work because of the active antagonistic effect over several fungi in postharvest organic pears. Yeast biomass production was carried out in a 15 L stirred-tank bioreactor with 12 L of working volume at 20 °C and 300 rpm and 0.64 vvm of aeration. The selected production medium was based on cheese whey powder and salts. The present study aims to evaluate the possibility of using an inexpensive growth substrate for production of added value products (yeast biomass), this innovation also requires evaluate biocontrol efficacy of yeast against fungal diseases of pears in semi-commercial assays. The yeast biomass was collected, cold stored for 60 days (Treatment 1) and 15 days (Treatment 2) and sprayed on the pears in semi-commercial level testing assays. After 180 days of postharvest conservation, significant reduction of fungal infection by Penicillium expansum, Botrytis cinerea and Cladosporium sp. was observed. The Treatment 1 reduced total diseases incidence by 71%, instead Treatment 2 reduced it by 92%. The effect of spray application on the yeast viability with different cold storage was tested. These work provides information on the bench-scale bioreactor yeast production using a new low-cost medium, viability and biocontrol efficacy of Vishniacozyma victoriae in controlling common diseases affecting pears in semi-commercial assays.

Development of low-cost formulations of plant growth-promoting bacteria to be used as inoculants in beneficial agricultural technologies.

Phosphorus is one of the main macronutrients for plant development. Despite its large deposits in soils, it is scarcely available for plants. Phosphate-solubilizing bacteria, belonging to the group of plant growth-promoting rhizobacteria (PGPR), are capable of mobilizing deposits of insoluble phosphates in the soil. The use of PGPR as inoculants provides an environmentally sustainable approach to increase crop production. The effectiveness of inoculants depends on their proper production, formulation and storage in order to ensure the application of the required number of viable microbial cells. In order to develop inexpensive technology, low-cost compounds for biomass production and protection should be used. After the biomass production process, the product should be formulated in a liquid or a solid form, taking into account required storage time, use of protectors/carriers, storage conditions (temperature, humidity, etc.), ease of application and maintenance of beneficial effects on crops. Careful determination of these optimal conditions would ensure a low-cost efficient inoculant that would promote the growth and yield of various crops.