Characterization of Serratia marcescens: Prodigiosin Synthesis under Various Environmental Conditions and Biofilm Formation

Serratia marcescens is known for its high production of prodigiosin, a pigment that serves as a virulence factor and possesses beneficial biological, antibacterial, antifungal, and antimalarial characteristics. Another virulence factor of Serratia marcescens is the ability to produce biofilms, which are aggregations of microorganisms adhering to surfaces surrounded by self-produced matrix. These biofilms pose many health risks in the milk production and processing industry, such as milk spoilage, poor-quality milk products, and other health risks. Our study revealed that, after 24 hours of incubation at 30°C, colonies on Chrome agar appeared pink with a dark center while on nutrient agar colonies appeared red at 28°C due to Serratia marcescens' ability to produce pigment. the ability of these local isolates to produce pigment was evaluated using NB Medium with different incubation time A total of 11 isolates from milk samples showed the ability to produce a high concentration of prodigiosin when incubated for 72 hours. All isolates were found to produce biofilm at different rates. In isolate (6), we observed the highest production of biofilm.