Bioreactor Community Ecology

The Bioreactor Community Ecology programme employs laboratory-scale bioreactors of varying sizes and dimensions to investigate how microbial community structure and function are affected by varying experimental conditions, and to evaluate and apply ecological theory derived from higher organisms in the context of microbial biofilm communities.

Eukaryote ecology has a rich ecological theory derived from studying a vast array of systems, both terrestrial and marine. Researchers at SCELSE are utilising this wealth of knowledge by extending the ecological models formulated for eukaryote ecosystems to microbial biofilm communities.
The highly complex biofilm communities present in activated sludge bioreactors provide a tractable system in which to study the interactions of microorganisms from a community ecology perspective, with the dual advantage of elucidating the hidden ‘universe’ of microbes performing such intricate functions. 

Studies of microbial community dynamics and functional responses include:

  • The involvement of bioaugmentation in species turnover rates in bioreactors and the long-term effects. [link to Falk et al 2013]
  • Support vector regression machine learning model as a successfully predictor of bioreactor performance [link to Seshan et al 2014]
  • Disturbance ecology: stable functional state of a natural community in a controlled setting 
  • The ecological role of quorum sensing in complex, multi-species communities, in the context of community assembly [Tan et al 2014]
  • Microbial granular biofilm assembly:  Community quorum sensing signalling and quenching [link to Tan et al 2015]

These studies provide the datasets required to test and formulate ecological hypotheses for community dynamics, and develop predictive models of process engineering. 

Bioreactors are widely used in today’s used water treatments, and they form an integral step in the liquid treatment of the process.  A bioreactor is a generic term for a system that degrades contaminants in water or soil with the use of microorganisms. In treating used water, bioreactors commonly exist as a chamber, within which raw materials are converted to desired products, catalysed by the discriminative use of enzymes, bacteria or plant and animal cells. 

Bioreactors can operate as full-scale, pilot-scale or laboratory-scale, all three of which serve different purposes and deliver different benefits. A full-scale bioreactor is a large reactor utilised in used water treatment plants and other major industrial projects. Pilot-scale bioreactors are smaller and are used to mimic the desired process in order to evaluate full-scale bioreactor design.

Laboratory or bench-scale bioreactors are compact and light. These bioreactors are the smallest of the three, and their utility lies in experimental manipulation of operational parameters such as pH and O2 availability to address key scientific questions.