RESUMO
Objective: To study the physiological and biochemical characteristics of four dominant microorganisms and the yellow pigment content of Pinelliae Rhizoma Fermentata (PRF), and provide basis for exploring the mechanism of PRF processing. Methods: The optimum growth temperature and pH value of the four dominant microorganisms Bacillus subtilis, Paecilomyces variotii, Byssochlamys spectabilis, and Aspergillus niger were studied. The ability of producing acidase, amylase, protease, and yellow pigment were determined. The yellow pigment content of each sample at different fermentation time points in process of PRF was determined. Results: The most suitable growth temperatures for B. subtilis, P. variotii, B. spectabilis, and A. niger were 35 ℃, 29 ℃, 29-31 ℃, and 39 ℃; And the optimum pH were 7.0, 7.0, 7.5, and 7.0, respectively. Four kinds of microorganisms had the ability to produce amylase and protease. P. variotii and B. spectabilis had the ability to produce yellow pigment. The content of yellow pigment were 69.875, 69.875, 71.750, 119.500, and 137.875 μg/g in the samples at different time points. Conclusion: Four kinds of dominant microorganisms may play an important role in fermentation process of PRF.