Extracellular enzymes and microbial cheaters

Pseudomonas cultures

Microbes produce extracellular enzymes and secrete them outside the cell membrane to break down complex chemical structures. These enzymes serve a dual purpose: they allow microbes to derive energy and nutrients from complex polymers, and they also catalyze the cycling of organic matter in ecosystems. However, enzyme producers face a conundrum because extracellular enzymes operate outside the cell and microbial competitors (“cheaters”) could avoid the cost of enzyme production by intercepting the products of the enzymatic reaction. We are using Pseudomonas bacteria as a model system to determine how cheating from microbial competitors affects enzyme production and substrate degradation. These results are being used to test a theoretical model of enzyme production in the presence of cheaters.

Funded by NSF Advancing Theory in Biology and NSF Evolutionary Processes

© Steven Allison 2012