Capillary electrophoresis for the monitoring of phenolic compounds in bioprocesses.

Hydrolysates of lignocellulosic biomass, used as substrates for the sustainable production of fuels and chemicals often contain high amounts of phenolic compounds inhibiting the production microbiota. Quantification of these inhibitor compounds may help to understand possible difficulties in bioprocessing and further the development of more efficient, robust and tolerable processes. A separation method based on capillary electrophoresis with UV detection was developed for the simultaneous quantification of 10 phenolic compounds that may have inhibitor properties. Intraday relative standard deviations were less than 0.7% for migration times and between 2.6% and 6.4% for peak areas. Interday relative standard deviations were less than 3.0% for migration times and between 5.0% and 7.2% for peak areas. The method was applied to demonstrate that Saccharomyces cerevisiae was able to decrease the concentrations of vanillin, coniferyl aldehyde, syringaldehyde, acetoguaiacone and cinnamic acid during the cultivation, whereas the concentrations of phenols increased.