ABSTRACT
Objective:To detect the colony number of bacteria, yeasts and molds in fermentation process of Pinelliae Rhizoma Fermentata (PRF), microbial flora species, and quantitatively analyze the dynamic changes of four dominant microorganisms at different fermentation time points of PRF, so as to provide experimental basis for exploring the processing mechanism of PRF. Method:According to Pharmaceutical Standard Preparation of Traditional Chinese Medicine Prescription of Ministry of Health of the People's Republic of China (the 10th volume), PRF was processed. The samples at five different fermentation time points (0, 30, 60, 90, 120 h) of PRF were taken, the culturing, isolation and purification of bacteria, yeasts and molds were carried out with selective media, and the colonies were counted. Fluorescence quantitative polymerase chain reaction (PCR) technique was employed to conduct absolute quantification of Bacillus subtilis, Paecilomyces variotii, Byssochlamys spectabilis and Aspergillus niger. The recombinant plasmids of these 4 microorganisms were used as the standard substances, and the standard curves were prepared after dilution of multiple ratios, quantitative analysis was performed on these 4 microorganisms in five samples at different processing time points (0, 30, 60, 90, 120 h) of PRF. Result:During the fermentation process of PRF, the number of bacteria was low with smooth change, while molds and yeasts grew dramatically at the late stage of fermentation and reached 1×106 CFU·mL-1 at the end of fermentation. At 5 different fermentation time points, the copy numbers of Bacillus subtilis were 3.53×105, 7.56×104, 1.58×105, 1.90×106, 1.85×106 copies·g-1, the copy numbers of Paecilomyces variotii were 0, 0, 0, 3.45×107, 4.15×108 copies·g-1, the copy numbers of Byssochlamys spectabilis were 0, 0, 0, 1.04×108, 2.28×108 copies·g-1, the copy numbers of Aspergillus niger were 0, 0, 9.48×105, 1.47×106, 7.56×106 copies·g-1, respectively. Conclusion:The change trend of microflora in the fermentation process of PRF can be reflected by the dynamic change of four dominant microorganisms, and molds may play an important role in the processing of PRF. Fluorescence quantitative PCR technique has the advantages of rapidity, sensitivity, good repeatability and high specificity, it is suitable for exploring processing mechanism of PRF.
ABSTRACT
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.
ABSTRACT
To investigate the microbial species, amount changes as well as the isolation and identification of domain strains at different fermentation time points of Pinelliae Rhizoma Fermentata, and provide basis for exploring the mechanism of Pinelliae Rhizoma Fermentata processing. Five samples were chosen at the time points (0, 18, 36, 54, 72 h) of Pinelliae Rhizoma Fermentata processing. Bacteria, mold and yeast from the samples were cultured; their colonies were counted, and the dominant strains were isolated and purified. The dominant bacteria and dominant fungi were identified by 16S rDNA and 26S rDNA sequencing respectively. The results showed that the bacteria count was low with slow and smooth changes in the fermentation process;while mold and yeast grew dramatically after 54 h culturing and reached 1×107 CFU•mL⁻¹ at the end of fermentation. Through the NCBI homology alignment and phylogenetic tree construction, the dominant bacteria were identified as Streptomyces sp., Bacillus pumilus, B. subtilis, B. aryabhattai and other Bacillus sp.; the dominant yeast was identified as Meyerozyma guilliermondii; the dominant mold were identified as Paecilomyces variotii, Byssochlamys spectabilis, and Aspergillus niger in the processing of Pinelliae Rhizoma Fermentata. The results indicated that multiple microbe species, especially yeast and mold, played a role in the fermentation processing of Pinelliae Rhizoma Fermentata. M. guilliermondii, P. variotii, P. variotii and A. niger and Bacillus sp. can be the crucial factors in the processing of Pinelliae Rhizoma Fermentata.