Aureobasidium pullulans strain Ach1-1 a potential biocontrol agent of postharvest diseases of apples

Aureobasidium pullulans strain Ach1-1was isolated form the surface of Golden Delicious apple fruit. The strain Ach1-1 was tested for their efficiency against variable strains of P. expansum the causal agent of bleu mold infection disease of apples in postharvest conditions.
The efficacy of strain Ach1-1 was monitored on time along a period of 5, 7 and 10 days storage at 25°C and one to six months storage at 4°C. The ability of Ach1-1 to control P. expansum infection was evaluated through disease incidence (%) and severity (lesion diameter cm) the results showed that strain Ach1-1 display high efficacy to control bleu mold infection disease compared to chemical fungicide and Boniprotect., and sustain this efficiency along a storage period of 4 months at 4°C. Which make it a well-placed Biocontrol agent to manage post-harvest disease of apples.
Besides, the industrial production of the yeast strains was carried out using the Fed Batch technology and freeze drying process. The efficacy of the produced strain was investigated, and results showed lower biocontrol efficiency than the active yeast. Hence a downstream formulation trials were carried out in an attempt to enhance the efficacy of produced yeast using amino acids, salts, and polyols. The results showed that the application of some adjuvants individually may enhance the efficiency of the yeast applied at low concentration