Tyrolian Science Fund project PhenylopH
The effects of phenyl acids on the anaerobic microbial community at different pH regimes
Eva M. Prem
In biogas reactors, phenyl acids like phenylacetate (PAA), phenylpropionate (PPA), and phenylbutyrate (PBA) are break-down products during the (anaerobic) degradation of lignin, lignocellulose, and proteinaceous materials. Phenyl acids can negatively affect microbial groups and thus lead to process disturbances in biogas reactors. However, it is not comprehensively understood so far, which physico-chemical and microbiological parameters influence the inhibitory effect of phenyl acids on the microbial communities. In this current project, the focus lies on the effects of PAA, PPA, and PBA on the microbial communities at different pH levels. Based on the pKa of the respective phenyl acid, the incubation temperature, and the pH of the reactor, phenyl acids are present in charged or uncharged form. As uncharged molecules are more likely to pass the cell membrane and thus affect the microorganism, it is important to understand the effects of (uncharged) phenyl acids in biogas reactors at varying pH levels.