Analysis of productivity and stability of synthetic microbial communities

Abstract

<jats:p>Bioreactors that employ a synthetic microbial community hold potential to overcome limitations of those based on a single species, which embrace a higher level of complexity due to the inter-species interactions. In this work, a number of generic system structures involving two cross-feeding species and various types of inhibition have been studied, together with two three-species cases where a third species is introduced to fulfil a specific function. These cases are represented by mathematical models and inspected through bifurcation analysis and numerical simulation to reveal how the system structure and parametrization affect stability and productivity of the bioreactor. The results show that inhibitions generally lead to reduction in both productivity and stability, and that the presence of a negative feedback loop and a positive feedback loop may give rise to oscillation and bi-stability, respectively, depending on the strength of the inhibitions involved. The intended gains by the introduction of a third species may be achieved when its negative side-effect is sufficiently moderate, and at the cost of reduced stability. As observed in several cases, the changes in stability and productivity do not always follow the same trend, implying trade-off between the two objectives in the engineering of such bioreactors.</jats:p>

Enhanced production of heterologous proteins by a synthetic microbial community: Conditions and trade-offs

“…Our results show that questions on the relation between growth and metabolic load appear on the community level as well, and are important for assessing the productivity of synthetic consortia. Whereas the biomass concentration attained, in the absence of the production of a heterologous protein, has sometimes been used as a proxy for the productivity of a consortium [59], our analysis shows that subtle effects involving feedback from metabolic load to growth may be at work. For example, in our system maximal productivity is obtained for a dilution rate where the total biomass concentration is suboptimal.…”

Best Operating Conditions for Biogas Production in Some Simple Anaerobic Digestion Models

“…It is the subject for future research directions. The determination of the OD and the optimal productivity of synthetic microbial communities considered in [65] is also an interesting question that deserves further attention.…”

Microbial model communities: To understand complexity, harness the power of simplicity

“…A community-intrinsic property could be defined as a behavior or outcome that cannot be predicted from the sum of the parts of the community [72] . Such a property could, for example, be stable oscillations in species abundances or predator–prey dynamics [74] but could also be an entity indicative of collective community function, such as increased biofilm formation in a community setting compared to what is produced by the individual species alone. The latter scenario will be used an example in the following text.…”