The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae.
The metabolic costs of improving ethanol yield by reducing glycerol formation capacity under anaerobic conditions in Saccharomyces cerevisiae.
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DOI：
10.1186/1475-2859-12-29
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发表时间：
2013-03-28
影响因子：
6.4
通讯作者：
Guillouet SE
中科院分区：
文献类型：
--
作者：
Pagliardini J;Hubmann G;Alfenore S;Nevoigt E;Bideaux C;Guillouet SE
通过调节速率控制酶甘油-3-磷酸脱氢酶（GPDH）的表达，通过甘油途径精细调节碳通量，是一种很有前途的方法，可以将碳从甘油重定向到乙醇，从而提高乙醇生产中的乙醇产量。在这里，利用GPD1启动子工程和GPD2缺失的菌株来研究减少酿酒酵母甘油产量而不损害其在乙醇生产过程中应对工艺应激的能力的可能性。为此，在厌氧条件下对GPD1残留表达不同的突变菌株TEFmut7和TEFmut2进行了研究。这两种菌株的甘油产量分别降低了44%和61%，而乙醇产量分别提高了2%和7%。乙醇产量最高的菌株TEFmut2的生物量产量降低了28%。甘油形成的调节导致了深刻的氧化还原和能量变化，导致ATP产率（YATP）的降低和有机酸（醋酸酯、丙酮酸酯和琥珀酸酯）的产生的调节。这些代谢重排导致突变体的乙醇损失和应激耐受性，这与之前在有氧作用下观察到的情况相反。这项工作展示了微调途径工程的潜力，特别是当必须在高产品产量与可接受的生长、生产力和抗逆性之间找到妥协时。以往的研究表明，与厌氧相反，在好氧条件下，乙醇产量的增加并不伴随着乙醇耐受性的损失。此外，这些突变体仍然能够在厌氧SSF过程中产生高达90 gl-1的乙醇。因此，微调代谢策略可能为进一步开发具有提高乙醇产量的健壮菌株提供令人鼓舞的可能性。
Finely regulating the carbon flux through the glycerol pathway by regulating the expression of the rate controlling enzyme, glycerol-3-phosphate dehydrogenase (GPDH), has been a promising approach to redirect carbon from glycerol to ethanol and thereby increasing the ethanol yield in ethanol production. Here, strains engineered in the promoter of GPD1 and deleted in GPD2 were used to investigate the possibility of reducing glycerol production of Saccharomyces cerevisiae without jeopardising its ability to cope with process stress during ethanol production. For this purpose, the mutant strains TEFmut7 and TEFmut2 with different GPD1 residual expression were studied in Very High Ethanol Performance (VHEP) fed-batch process under anaerobic conditions. Both strains showed a drastic reduction of the glycerol yield by 44 and 61% while the ethanol yield improved by 2 and 7% respectively. TEFmut2 strain showing the highest ethanol yield was accompanied by a 28% reduction of the biomass yield. The modulation of the glycerol formation led to profound redox and energetic changes resulting in a reduction of the ATP yield (YATP) and a modulation of the production of organic acids (acetate, pyruvate and succinate). Those metabolic rearrangements resulted in a loss of ethanol and stress tolerance of the mutants, contrarily to what was previously observed under aerobiosis. This work demonstrates the potential of fine-tuned pathway engineering, particularly when a compromise has to be found between high product yield on one hand and acceptable growth, productivity and stress resistance on the other hand. Previous study showed that, contrarily to anaerobiosis, the resulting gain in ethanol yield was accompanied with no loss of ethanol tolerance under aerobiosis. Moreover those mutants were still able to produce up to 90 gl-1 ethanol in an anaerobic SSF process. Fine tuning metabolic strategy may then open encouraging possibilities for further developing robust strains with improved ethanol yield.
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最大限度地减少工业乙醇酵母中的甘油合成而不影响其发酵性能
影响因子：
8.4
作者：
Guo, Zhong-peng;Zhang, Liang;Shi, Gui-yang
通讯作者：
Shi, Gui-yang
中断工业酒精酵母中的甘油途径以提高乙醇产量
影响因子：
5
作者：
Guo, Zhong-peng;Zhang, Liang;Shi, Gui-Yang
通讯作者：
Shi, Gui-Yang
影响因子：
3.2
作者：
GIRBAL, L;SOUCAILLE, P
通讯作者：
SOUCAILLE, P
影响因子：
3.2
作者：
BRANDRISS, MC;MAGASANIK, B
通讯作者：
MAGASANIK, B
影响因子：
7
作者：
Förster, J;Famili, I;Nielsen, J
通讯作者：
Nielsen, J