Determination of biofilm formation capacity of Metschnikowia reukaufii strain

Abstract

Objective: Biofilm is a community of microorganisms attached to biotic or abiotic surfaces. Microorganisms that form biofilms cause much more serious medical and industrial problems than their planktonic forms. In this sense, the ability of microorganisms to form biofilms must be known and precautions must be taken. The aim of this study is to create stress in the Metschnikowia reukaufii MN622824 strain, whose inhibitory substance production increases under stress conditions, by trying different environmental conditions and to determine its effect on biofilm formation. In addition, to observe its effect on biofilm formation on stainless steel (SS) surfaces, which are frequently used in food machines. Methods: Biofilm formation was compared with the tube method and the microtitration plate method. For this purpose, 5 different media compositions containing 5% glucose, 10% glucose, 5% NaCl, 10% NaCl, containing no glucose and NaCl (sodium chloride), and 3 different incubation periods consisting of 3, 5 and 7 days were tested. Additionally, scanning electron microscopy imaging was performed to examine the adhesion of biofilm to stainless steel coupons. Results: In the tube method, the highest biofilm formation was observed after three days of incubation in tubes with 5% glucose added. No biofilm was formed in the tubes that were kept for seven days or 10% NaCl was added. In the microtitration plate method the strong biofilm formation (1.3022) was obtained after three days of incubation in a medium containing 5% glucose. In the control group without glucose and NaCl, moderate biofilm formation were observed on the 3rd day (0.7385) and the 5th day (0.6882). Biofilm formation was evaluated as absent or weak in media containing 10% glucose or NaCl. As glucose and NaCl concentrations increased, biofilm formation decreased. Reticular bond structure showing biofilm formation were imaged with a scanning electron microscope in the control group on days 3–5–7, 5% NaCl and 5% glucose concentration on the 3rd day, and 5% glucose concentration on the 5th day. Conclusion: Biofilm formation in food factories poses a significant health problem. It was observed that increasing NaCl, glucose concentration and incubation time negatively affected the biofilm formation of the Metschnikowia reukaufii strain. Biofilm formation decreases or disappears in yeasts exposed to stress conditions. It is thought that the data obtained will help in biofilm control. © (2024), (Refik Saydam National Public Health Agency (RSNPHA)). All rights reserved.