Rediscovering bacterial exopolysaccharides of terrestrial and marine origins: novel insights on their distribution, biosynthesis, biotechnological production, and future perspectives

Abstract

Bacteria exist in colonies as aggregates or associated with surfaces forming biofilms rather than planktonic cells. Living in such a unique manner is always mediated via a matrix of extracellular polymeric substances, which are composed mainly of polysaccharides or specifically exopolysaccharides (EPS). Biofilm formation and hence EPS production are affected by biotic and abiotic factors inducing/inhibiting several involved genes and other molecules. In addition, various aspects of bacterial EPS regarding: physiological functions, molecular weight, and chemical composition were demonstrated. Recent investigations have revealed a wide spectrum of EPS chemical and physicochemical properties showing promising applications in different industrial sectors. For instance, lactic acid bacteria (LAB)- and marine-derived EPS exhibit: immunomodulatory, antioxidant, antitumor, bioremediation of heavy metals, as well as thickening and viscosity modifiers in the food industry. However, bacterial EPS have not yet been commercially implemented, in contrast to plant-derived analogues. The current review aims to rediscover the EPS structural and biosynthetic features derived from marine and terrestrial bacteria, and applications as well.

Keywords:

• Bacteria
• biofilm
• biotechnology
• exopolysaccharides
• marine

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

Ahmed Zayed and Roland Ulber would like to thank the “Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)-Project-ID [172116086-SFB 926] “for project funding. In addition, Mohamed A. Farag acknowledges the financial support received from the Alexander von Humboldt Foundation, Germany.