The Role of Matrix Components in Multispecies Coexistence in Biofilms

Bacterial communities are diverse and shaped by interspecies interactions. In biofilms, the extracellular matrix impacts these interactions, affecting community functionality, diversity, and survival. The matrix ensures spatial rigidity and compartmentalization while also generating gradients and protection. In this chapter, we review the importance of the biofilm matrix for bacterial social interactions. Social evolution theory of microbes is introduced and discussed in the context of biofilm formation, introducing classification terms of relevance to multispecies biofilms. This chapter also highlights the importance of community-intrinsic properties and presents examples of such properties, their effects, and underlying mechanisms in biofilms. Finally, we review a four-species model system with an intriguing level of synergy with respect to overall community properties, effects on the individual species, and potential applicability in biotechnological and industrial settings. In summary, this chapter describes the fascinating world of interspecies interactions, focusing on their facilitation by and impact on the biofilm matrix, and emphasizes the need for considering multiple species in future biofilm research.