Vol. 10, Issue 5 (2021)

Author(s):
Jasmin Thomas and Jayanta Saha

Abstract:
The application of yeast based biocontrol formulation is safe and economic alternative for reducing post-harvest fungal decay of fruits. Development of formulation is an important step in the application of a biocontrol agent. When the yeast is in an environment with high osmolarity, water flows from the cell into the extracellular medium. This results in a decrease in the cellular volume and turgor pressure and may result in cell death. Tolerance to osmotic stress is a prerequisite for development of biocontrol yeast formulation. The current study was aimed to evaluate the antagonistic property of yeast isolate and its osmotic stress tolerance capacity. The antagonistic property of Y-27 (Meyerozyma caribbica) was evaluated against Colletotrichum musaeby dual culture method in vitro. The viability of antagonistic yeast in molasses urea based liquid formulation was evaluated after exposing them to osmotic stress with molasses urea media containing salt at different concentration and also with changing the concentration of molasses. The number of viable cells (Colony forming units per millilitre) was counted with modified serial dilution method. Meyerozyma caribbica showed an antagonistic property against the test pathogen. The cells were grown in the control formulation showed a significant change in the cell size and shape compared to the formulations which induced osmotic stress. It was generally observed that as salt concentration increases, the viability of cells increases but the cell multiplication rate decreased proportionally.The formulation prepared with yeast isolate was found highest viability in 1% NaCl and 15% molasses added separately up to 120 and 60 days of storage respectively.