Systems Biology of Microbial Exopolysaccharides Production

Abstract

Exopolysaccharides (EPSs) produced by diverse group of microbial systems are rapidly emerging as new and industrially important biomaterials. Due to their unique and complex chemical structures and many interesting physicochemical and rheological properties with novel functionality, the microbial EPSs find wide range of commercial applications in various fields of the economy such as food, feed, packaging, chemical, textile, cosmetics and pharmaceutical industry, agriculture, and medicine. EPSs are mainly associated with high-value applications, and they have received considerable research attention over recent decades with their biocompatibility, biodegradability, and both environmental and human compatibility. However, only a few microbial EPSs have achieved to be used commercially due to their high production costs. The emerging need to overcome economic hurdles and the increasing significance of microbial EPSs in industrial and medical biotechnology call for the elucidation of the interrelations between metabolic pathways and EPS biosynthesis mechanism in order to control and hence enhance its microbial productivity. Moreover, a better understanding of biosynthesis mechanism is a significant issue for improvement of product quality and properties and also for the design of novel strains. Therefore, a systems-based approach constitutes an important step toward understanding the interplay between metabolism and EPS biosynthesis and further enhances its metabolic performance for industrial application. In this review, primarily the microbial EPSs, their biosynthesis mechanism, and important factors for their production will be discussed. After this brief introduction, recent literature on the application of omics technologies and systems biology tools for the improvement of production yields will be critically evaluated. Special focus will be given to EPSs with high market value such as xanthan, levan, pullulan, and dextran.

A systematic pipeline for classifying bacterial operons reveals the evolutionary landscape of biofilm machineries

“…EPS are an important constituent of bacterial biofilms that not only ensure survival in response to limited nutrient availability, but are also involved in antibiotic tolerance, immune evasion and serve as virulence factors in many clinically relevant pathogens (19–21). Distinct mechanisms have been identified in the production of bacterial EPS, including the well-characterized Wzx/Wzy and ABC transporter-dependent pathways involved in capsular polysaccharide and lipopolysaccharide secretion in Gram-negatives (22), and the more recently identified synthase-dependent systems(23).…”

Absorption, distribution, metabolism and elimination (ADME) and toxicity profile of marine sulfated polysaccharides used in bionanotechnology

“…Production of microbial exopolysaccharides involves huge expenditure which can be reduced and productivity can be optimized through deeper understanding of interrelations between metabolic pathways and EPS biosynthesis mechanism and by application of omics technologies and systems biology tools. Acquired knowledge will also enable in improving product quality and characteristics and also design of novel strains capable of yielding new molecules with modified composition and chain length (Ates, 2015). Alternatively, a list of structural characteristics essential to their optimal performances can be prepared for each of the polymer, against which matching can be done, when isolated from a new source or same source but under different conditions (Rouzet et al, 2011;Rujitanaroj et al, 2014;Salek and Gutierrez, 2016).…”

“…(Majee et al, 2017b). Bacterial EPS which is comparatively a new entrant is mauran, a sulfated anionic EPS which reveals itself with immense potential (Ates, 2015).…”

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“…Cellular adaptation to limiting factors, such as stress conditions, osmolarity of the medium, ammonium and phosphate availability also influence EPS biosynthesis in a coordinated fashion. Recently, Ates 85 has analyzed the application of omics technology and system biology tools in understanding the microbial EPS biosynthesis mechanism and regulation and pointed out that the general mechanisms of bacterial polysaccharide production involve Wzx/Wzy-dependent pathway, the ATP binding cassette (ABC) transporter-dependent pathway and the synthase-dependent pathway, while the extracellular synthesis is accomplished by the use of a single sucrase protein. On the contrary, information related to the genetics of microbial EPS biosynthesis particularly the identification of genes involved in the assembly of repeat units, polymerization, transportation and regulation are know only for the biosynthesis of xanthan, levan and dextran, however, genetic data pertaining to EPS biosynthesis by halophilic microorganisms is scanty.…”