Selection of Feruloyl Esterase-producing Strains and Estimation of Phenolic Acid Production

Abstract:

The agar plate screening and Oxford cup testing methods were used to select microorganisms that could produce feruloyl esterase. The isolated strains were inoculated into wheat bran for solid-phase fermentation. Spectrophotometry and High Performance Liquid Chromatorgphy (HPLC) were used to analyze the activity of feruloyl esterase as well as the quantity of total phenolic acid and ferulic acid released in the fermented wheat bran. The individual morphology, colony characteristics, and iternally transcribed spacer (TIS) sequencing analysis, and identification of the strains was performed. The results identified one screened strain with highest feruloyl esterase activity, with a peak value of 163.5 mU/g on the 4th day. In addition, this strain yielded higher amounts of total phenolic acids, with 6.6× increase in fermented wheat bran. Among the total phenolic acids, ferulic acid accounted for 0.697% and its production was enhanced by 0.22% compared to that in unfermented wheat bran. Molecular identification revealed 100% homology of this strain with Aspergillus clavatus, and it was named Yanqing. This strain has potential applications in improving ferulic acid content during wheat bran fermentation in the fields of agriculture, value-adding utilization of sideline products, and medicine.