Microbial communities, such as microbial biofilms, are dynamic structural
communities. The architecture and function of these communities is shaped by the
interaction with the surrounding environment and by the interactions between
community members. In most natural and man-made environments, microbial
communities host a plethora of different species. The community is a heterogeneous
structure with pH, oxygen and nutrient gradients creating suitable niches for a
diversity of life. Manuscript IV shows how different environments create unique
niches for different microbial communities, and that bacteria in different niches have
different potential for interacting.
Understanding the development of microbial communities is indispensable as
microbial communities, such as biofilms, are highly associated with chronic infections,
colonization of catheters and implants. Biofilms have also been associated with crop
promotion and pathogenicity and contamination of food products with spoilage and
potential pathogenic strains. Additionally, the use of microbial communities for
bioremediation, wastewater treatment and bio-energy could provide environmentally
friendly and low-cost alternatives to current technologies.
Unravelling the mechanisms influencing community development is not simple, as the
community is often the result of a range of mechanism all acting simultaneously. By
studying simpler model communities it is possible to restrict the diversity of acting
mechanisms, and study them individually. Using this approach, we show how a range
of mechanisms can influence community development of mixed species. In
Manuscript I we present how metabolic interplay can cause pH stabilization of the
environment, which in turn enhances community growth. Manuscript II identifies
cross feeding on amino acids as a potential driver for community development, while
emphasising that competition for limited resources also affect community
development. Manuscript V shows how facilitation of surface attachment can promote
community formation and how sharing of public goods can promote community
protection. Finally Manuscript III shows how individual mechanisms can affect each
other over time, and select for unique phenotypes in the community.