Cell characteristics of exopolysaccharides from four marine bacteria and microscopic observation

Abstract

In the field of microbiology, bacterial exopolysaccharide (EPS) have become a research hotspot due to their unique biological functions and broad application potential. However, EPS produced by different bacteria exhibit significant variations in yield, structure, and functionality, making an in-depth investigation of their properties crucial for unlocking their potential applications. This study selected four representative marine bacteria as research subjects, aiming to determine their growth curves during the synthesis of extracellular polysaccharides and to dynamically understand the relationship between b acterial growth and extracellular polysaccharide synthesis. Meanwhile, laser confocal microscopy and transmission electron microscopy techniques were employed to analyze the structural characteristics of extracellular pol ysaccharides at the microscopic level, providing a theoretical basis for revealing the synthesis mechanism of extracellular polysaccharides and optimizing the production process. The research results indicated that under the culture condition of 25oC, the four marine bacteria had similar physiological characteristics, entering the exponential growth phase at 2h-4h and the stable growth phase at 18h-24h. At the same time, the interaction between marine bacteria and extracellular polysaccharides showed asignificant time dependence, closely related to the four growth periods of bacteria. However, the extracellular polysaccharide yields during the stable growth phase varied among the four strains, ranging approximately from 0.18 g/L to 0.4 g/ L. This study analyzed 48 laser confocal microscopy images and 6 transmission electron microscopy images of Hao2018, elucidating the cellular characteristics of extracellular polysaccharides at the microscopic level. Through systematic research, it is expected to lay a foundation for the efficient development and utilization of bacterial extracellular polysaccharides and promote the development of related industries.