According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of ...According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of invertase gene （suc2 of Saccharomyces cerevisaie） under PXPR2 in new Y. lipolytica A-101 invertase positive （Suc＋） transformants their growth on Bioscreen C was analyzed. Minimal mineral medium with thiamine （MMT） and sucrose （1%）, adjusted to pH from 5.8 to 7.6 and supplemented by 0-0.1% of peptone was used. Biomass （OD）, maximal specific growth rate （μmax） and consumed sucrose were measured. Maximal yeasts growth, resulting from the optimal PXPR2 induction, was observed at pH 7.2 and with very low peptone doses （0.0025% and 0.01%）. For five clones （A-101 1356-5; A-101 B54-6; A-101 B57-4; A-101 A18 and W29 ura3-302） only 0.005% of peptone was needed. Amount of hydrolyzed sucrose varied from 24% to 83% and μmax from 0.06 to 0.28 hl. Suc^＋ clones differ in growth parameters, so the site of yeast cassette integration into genome influences expression level of suc2 under PXPR2. Designing large scale processes with Y. lipolytica Suc^＋ clones peptone concentration has to be 100 times smaller than recommended so far.展开更多
文摘According literature, the induction of Yarrowia lipolytica alkaline protease promoter （PXPR2） is efficient in pH 〉 6.0 and with high peptone dose. To establish optimal pH and peptone concentration for induction of invertase gene （suc2 of Saccharomyces cerevisaie） under PXPR2 in new Y. lipolytica A-101 invertase positive （Suc＋） transformants their growth on Bioscreen C was analyzed. Minimal mineral medium with thiamine （MMT） and sucrose （1%）, adjusted to pH from 5.8 to 7.6 and supplemented by 0-0.1% of peptone was used. Biomass （OD）, maximal specific growth rate （μmax） and consumed sucrose were measured. Maximal yeasts growth, resulting from the optimal PXPR2 induction, was observed at pH 7.2 and with very low peptone doses （0.0025% and 0.01%）. For five clones （A-101 1356-5; A-101 B54-6; A-101 B57-4; A-101 A18 and W29 ura3-302） only 0.005% of peptone was needed. Amount of hydrolyzed sucrose varied from 24% to 83% and μmax from 0.06 to 0.28 hl. Suc^＋ clones differ in growth parameters, so the site of yeast cassette integration into genome influences expression level of suc2 under PXPR2. Designing large scale processes with Y. lipolytica Suc^＋ clones peptone concentration has to be 100 times smaller than recommended so far.
