Acceleration of Yeast Autolysis by Addition of Fatty Acids, Ethanol and Alkaline Protease.

Background: Autolysate products from yeast origin are very interesting for food, feed, cosmetic, pharmaceutical, and fermentation industries. The lysis process greatly influences the quality and efficiency of the final autolysates.

Objectives: Here, we have compared four lysis methods based on autolysis, plasmolysis (with ethanol 1.5% (v/v) and coconut fatty acids 1% (w/w)) and hydrolysis (with alkaline protease 0.4 % (v/w)) on degrading the baker's yeast Saccharomyces cerevisiae.

Materials and methods: The efficiency of processes was evaluated according to the recovered solid and protein contents, release of intracellular materials, cell viability, microscopy imaging, degree of hydrolysis and electrophoresis studies.

Results: Results showed that the increased recovered solids and proteins, as well as a higher degree of hydrolysis (DH) were obtained for the enzymatic hydrolyzed cells using alkaline protease. SDS-PAGE analysis also confirmed the results. Further, functionality of the final products by agglutination test showed that the hydrolyzed cells could effectively bind pathogenic bacteria compared to the other cell lysates.

Conclusions: In conclusion, this work provides adequate evidence for efficiency of alkaline protease for producing the nutritional cell lysates from baker's S. cerevisiae used in food, feed, cosmetic, and pharmaceutical applications. Moreover, this was the first report on using coconut fatty acids and alkaline protease in lysis of baker's yeast.