Fermenting Distiller's Grains by the Domesticated Microbial Consortium To Release Ferulic Acid

The microbial consortium FA12 that can release ferulic acid (FA) by fermenting distiller's grains was screened from Daqu. Taibaiella, Comamonadaceae, and Ochrobacum were highly abundant in FA12 by 16S rRNA gene sequencing. In the process of long-term acclimation with distiller's grains as a medium, the biomass of FA12 remained stable, and the pH value of fermentation liquid was also relatively stable. Meanwhile, the activities of cellulase, xylanase, and feruloyl esterase secreted by FA12 were stable in the ranges of 0.2350-0.4470, 0.1917-0.3078, and 0.1103-0.1595 U/mL, respectively, and the release of FA could reach 133.77 μg/g. It is proven that the microbial consortium has good genetic stability. In addition, the structural changes of lignocellulose in distiller's grains before and after fermentation were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR), and the changes of distiller's grains weight and lignocellulose content before and after fermentation were also detected. These results all confirmed that FA12 had the function of degrading distiller's grains. In this study, we explored a method to use microbial communities to release FA from distiller's grains and degrade lignocellulose in the waste, which opened up a new way for the application of the high value of lost waste.