Growth-rate dependency of de novo resveratrolproduction in chemostat cultures of an engineered Saccharomycescerevisiae strain

Microbial Cell Factories

Research

Tim Vos¹  Pilar de la Torre Cortés¹  Pascale Daran-Lapujade¹  Walter M. van Gulik¹  Jack T. Pronk¹ 

[1] Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC, Delft, Netherlands;

关键词: Metabolic engineering;    Maintenance energy;    Anabolic products;    q;    Continuous culture;    Yeast;    Synthetic biology;   

DOI  :  10.1186/s12934-015-0321-6

 received in 2015-02-18, accepted in 2015-08-21,  发布年份 2015

来源: Springer

【 摘 要 】

IntroductionSaccharomyces cerevisiae has become a popularhost for production of non-native compounds. The metabolic pathways involvedgenerally require a net input of energy. To maximize the ATP yield on sugar inS. cerevisiae, industrial cultivation istypically performed in aerobic, sugar-limited fed-batch reactors which, due toconstraints in oxygen transfer and cooling capacities, have to be operated atlow specific growth rates. Because intracellular levels of key metabolites aregrowth-rate dependent, slow growth can significantly affect biomass-specificproductivity. Using an engineered Saccharomycescerevisiae strain expressing a heterologous pathway forresveratrol production as a model energy-requiring product, the impact ofspecific growth rate on yeast physiology and productivity was investigated inaerobic, glucose-limited chemostat cultures.ResultsStoichiometric analysis revealed that de novo resveratrol productionfrom glucose requires 13 moles of ATP per mole of produced resveratrol. Thebiomass-specific production rate of resveratrol showed a strong positivecorrelation with the specific growth rate. At low growth rates a substantialfraction of the carbon source was invested in cellular maintenance-energyrequirements (e.g. 27 % at 0.03 h−1). Thisdistribution of resources was unaffected by resveratrol production. Formation ofthe by-products coumaric, phloretic and cinnamic acid had no detectable effecton maintenance energy requirement and yeast physiology in chemostat. Expressionof the heterologous pathway led to marked differences in transcript levels inthe resveratrol-producing strain, including increased expression levels of genesinvolved in pathways for precursor supply (e.g. ARO7 and ARO9 involved inphenylalanine biosynthesis). The observed strong differential expression of manyglucose-responsive genes in the resveratrol producer as compared to a congenicreference strain could be explained from higher residual glucose concentrationsand higher relative growth rates in cultures of the resveratrol producer.ConclusionsDe novo resveratrol production by engineered S. cerevisiae is an energy demanding process. Resveratrolproduction by an engineered strain exhibited a strong correlation with specificgrowth rate. Since industrial production in fed-batch reactors typicallyinvolves low specific growth rates, this study emphasizes the need foruncoupling growth and product formation via energy-requiring pathways.

【 授权许可】

CC BY   
© Vos et al. 2015

【 图 表 】

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