ABSTRACT
An exopolysaccharide (EPS) is a polymer secreted by microbes in response to environmental stress conditions such as pH, temperature, and osmotic pressures (Feng et al., 2023; Nguyen et al., 2020). Various microbes including bacteria (Streptococcus, Lactococcus, Pediococcus, Lactobacillus, Leuconostoc, etc.), fungi (Agaricus blazi, Cordyceps sp., Ganoderma lucidum, Grifola frondose, Lentinus edodes, etc.), and algae (Chlorella zofingiensis, Scenedesmus sp. Chlorella vulgaris, Porphyridium cruentum, Chlorella pyrenoidosa, etc.) are able to produce EPS (Morais et al., 2022; Nguyen et al., 2020; Wan Mohtar et al., 2016). Exopolysaccharides are mainly composed of various sugars, proteins, fatty acids, and nucleic acids. Naturally, it helps microbes in surface attachment and protects against phagocytosis and improves the osmotic environment of cells to reduce the damage caused by the passage of toxic molecules or ions (Angelin and Kavitha, 2020). The production of EPS generally occurs intracellularly, and various pathways (active and passive) are involved to secret EPS (Dueholm et al., 2023). Exopolysaccharides are composed of several different sugar building blocks, and their properties vary with composition (Bhatia et al., 2022). Different microbes can produce various types of EPS, and it’s important to search for and explore new microbes for the production of EPS that have unique properties (Sathiyanarayanan et al., 2016). This research area is gaining interest around the globe, and the number of publications is increasing each year. According to the Scopus database, around 2,199 research and review articles have been published in the last few years (2019–2023). The top five countries involved in the microbial biopolymer research area include China (565), India (289), the United States (190), Italy (120), and Brazil (104) (Figure 1.1).
