Optimization of Carbon and Nitrogen Source in the Biotransformation Media of Baicalin by Aspergillus oryzae

Author(s): Mei He, Wenjie Chen, Lei Tian and De-Quan Qiu

Baicalin was an important effective component in Scutellariae radix, which had extensive pharmacological activities and had been widely applied in most drugs, but it couldn’t be easily absorbed by humans. However, aglycone baicalein has better pharmacological effects and high bioavailability but with lower contents in Scutellariae radix. In this study, Aspergillus oryzae was employed as the biotransformation microorganism. And then the biotransformation of baicalin and the optimization of the carbon source and nitrogen source in the biotransformation media were conducted. Generally, the best biotransformation media of baicalin by Aspergillus oryzae was optimized as the combination of 0.0017% arginine, 0.0017% valine, 0.0017% glutamic acid, 0.0017% alanine, 0.0017% histidine, 0.0017% tyrosine and 0.01% urea, 0.4% KH2PO4, 0.04% CaCl2, and 0.04% MgSO4, pH 6, with a biotransformation efficiency of 88.36%. Compared with using corncob, bran, glucose, dissoluble starch as carbon source, it was significantly better for the biotransformation of baicalin without carbon source except the substrate baicalin. The best nitrogen source was the combination of 0.01% urea and six amino acids. Comprehensively considering biotransformation efficiency and cost, 0.1% urea was also a good inorganic nitrogen source for the biotransformation of baicalin by Aspergillus oryzae.

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