Contents of eight saccharides in unprocessed and processed Rehmannia glutinosa and content changes at different processing time points / 中草药

Objective: To analyze the contents of eight saccharides in unprocessed and processed Rehmannia glutinosa by HPLC and to investigate the impacts of processing time on saccharides in R. glutinosa. Methods: HPLC conditions were as follows: Prevail Carbohydrate ES column (250 mm × 4.6 mm, 5 μm), flow rate of 0.8 mL/min, ELSD detector, acetonitrile as mobile A and water as mobile B for gradient elution. Results: Fructose, glucose, surcrose, melibiose, raffinose, manninotriose, stachyose, and verbascose were separated with good linear relationships within their corresponding concentration ranges, the r values were within 0.998 4-0.999 7; the average recovery was 97.5%-103.2%. The content analysis at different processing time points showed that surcrose, raffinose, stachyose, and verbascose exhibited decreasing trend during processing, while fructose, glucose, melibiose, and manninotriose exhibited significantly increasing trend. Conclusion: The proportions of saccharides in unprocessed and processed R. glutinosa are significantly different, and the results of this study could provide the data support for revealing the processing mechanism of R. glutinosa.

Improvement of Ethanol Fermentation by Expression of Schizosaccharomyces pombe mel Gene and Disruption of GPD1 in Saccharomyces cerevisiae / 微生物学通报

Based on homologous recombination,?-galactosidase gene mel from S.pombe was integrated to the chromosomal DNA of industrial S.cerevisiae and the key enzyme gene GPD1 of the glycerol anabolic pathway was disrupted contemporaneously,and recombinants were screened through increasing G418 concentration.It was shown that melibiose utility capability of recombinant S.cerevisiae MG1 was increased evidently,glycerol productivity was decreased,and the mel gene was expressed stabilized in the host cell.No impact on the cell character was appeared after introduced extrinsic gene,but the cells were flocculate when growing.When compared with parent industrial S. cerevisiae Y to ferment with corn powder and wheat starch as raw substrates,ethanol productivity was increased,glycerol productivity was decreased,and the melibiose in the broth was exhausted completely detected by HPLC analysis.