Biofilm Lifestyle of Thermophile and Acidophile Archaea.

Abstract

Biofilms represent a common and widespread microbial lifestyle on earth. Thissessile mode of growth is enabled by communities of microorganisms that areembedded in a self-produced matrix of extracellular polymeric substances (EPS).Biofilms can be found self-associated either as “floating mats” in air-water interfaces or as surface-associated communities of microorganisms. Microbial diversitywithin a biofilm can vary from few to hundreds of different species.The intrinsic advantages of the biofilm lifestyle are largely attributed to thepresence of EPS. EPS consist of macromolecules such as polysaccharides, proteins,nucleic acids, and lipophilic compounds. Secretion of EPS provides several goodsto the community: (i) a protective barrier against environmental changing conditions, (ii) a highly hydrated environment (as EPS can retain up to 90% water), (iii) anutrient source and an extracellular redox reactive space, (iv) co-metabolism and synergistic processes by providing a physical matrix where cell-cell interactions caneasily occur, (v) a prerequisite for the exchange of genetic material (Flemming andWingender 2010). In this chapter we review recent findings on biofilm formation inextremophilic archaea with a focus on acidophilic mineral dissolving species.