Metabolic engineering of Vit C: Biofortification of potato

Metabolic engineering of Vit C: Biofortification of potato

Ginseng contained many different kinds of saponin which was the most valuable for people, but its yield cannot satisfy the demand using traditional extract methods. Enzyme transformation is a conformable and highly performed method which was fit for today. A <TEX>${\beta}$</TEX>-glucosidase producing bacterium (<TEX>$DCY51^T$</TEX>) was isolated from Korean fermented-vegetable food kimchi. The 16S rRNA gene sequence analysis revealed that the strain <TEX>$DCY51^T$</TEX> belongs to the genus Lactobacillus. The highest sequence similarity was found with Lactobacillus paracollinoides LMG <TEX>$22473^T$</TEX> and Lactobacillus collinoides LMG <TEX>$9194^T$</TEX> with levels of 16S rDNA similarity of 97.4% and 97.3%, respectively. Based on the above results the strain <TEX>$DCY51^T$</TEX> placed in the genus Lactobacillus and proposed a new species, Lactobacillus kimchicus sp. nov. <TEX>$DCY51^T$</TEX> (= KCTC <TEX>$12976^T$</TEX> = JCM <TEX>$15530^T$</TEX>). It was culture solution reacted with Red Ginseng extract and <TEX>$Rb_1$</TEX>, respectively. The medium of bacteria was the liquid of MRS, the temperatures of growing and reacting between bacteria liquid and saponin were samely <TEX>$37^{\circ}C$</TEX>, there spective reacting time were 12 hours and 48 hours. Thus we got different saponins, and TLC and HPLC analysis showed that: enzyme respectively reacted with <TEX>$Rb_1$</TEX> and Red Ginseng extract got the transformed saponin, respectively. The polarity position in TLC was a little higher than Rd; and the polarity position was the same as that of Compound K's, the saponin obtained from HPLC and other experimental results was not Compound K. The constitution of its saponin was hoped to be further confirmed.