Metabolism and release of characteristic components and profiles of enzymatic activities during fermentation of Massa Medicata Fermentata

Various enzymes secreted by microorganisms during fermentation of Massa Medicata Fermentata (MMF) play a crucial role in conversion of the chemical substances for better clinical application. However, enzyme-driven transformation of chemical compounds during MMF fermentation has not been fully unveiled. Our findings revealed that MMF fermented with a mixture of wheat bran (WB)-flour (2:1) was observed with high enzymatic activities, alongside distinguished appearance. The activities of protease, ester bond hydrolase for cCGA and EF, and glycoside hydrolase all increased with the extended fermentation time of MMF, reaching 14.84×10 −8 ±0.3436×10 −8 , 0.05456×10 −8 ±0.0017×10 −8 , 0.5715×10 −8 ±0.1285×10 −8 , and 15.25×10 −8 ±0.01389×10 −8 Kat/g on the 8th day of fermentation. Moreover, protease has been proven to drive the conversion of WB proteins into amino acids by precolumn phenyl isothiocyanate derivatization. Besides, transformation patterns of ester bond hydrolase on substrate components were revealed, in which cryptochlorogenic acid was decomposed into caffeic acid and quinic acid, and ethyl ferulate was metabolized into ferulic acid. By glycoside hydrolase, amygdalin was transformed into prunasin and benzaldehyde. This study reveals the enzyme-mediated transformation patterns of the focused components during fermentation of MMF, laying foundation for further elucidation of its fermentation mechanism and elevation of quality control. • Variations in wheat bran-flour proportions significantly influence enzymatic activity in MMF. • Amino acids are produced from proteins mediated by protease in MMF. • Cryptochlorogenic acid is converted into caffeic acid and quinic acid induced by ester bond hydrolase in MMF. • Ester bond hydrolase catalyzes the decomposition of ethyl ferulate into ferulic acid in MMF. • Glycoside hydrolase activity in MMF is demonstrated by transforming amygdalin into prunasin and benzaldehyde.