Increased Acetate Ester Production of Polyploid Industrial Brewer's Yeast Strains via Precise and Seamless "Self-cloning" Integration Strategy.

Background: Enhancing the industrial yeast strains ethyl acetate yield through a precise and seamless genetic manipulation strategy without any extraneous DNA sequences is an essential requisite and significant demand.

Objectives: For increasing the ethyl acetate yield of industrial brewer's yeast strain, all the alleles were overexpressed through "self-cloning" integration strategy.

Material And Methods: strain DH5α was utilized for plasmid construction.

Construction of industrial baker's yeast with high level of cAMP.

Cyclic adenosine monophosphate (cAMP) plays an important role in modulating the activity of microbe cell. In this study, PKA (protein kinase A) activity was weakened through truncation of TPK2 promoter (-150 bp and -300 bp) and gene deletion of BCY1 (encodes the regulatory subunit of PKA), TPK1 and TPK3, generating strains BY9a-T2-150 and BY9a-T2-300, respectively. High-performance liquid chromatography analysis showed cAMP levels in BY9a-T2-150 and BY9a-T2-300 were increased by 5- and 18-fold, respectively, compared with that of parent strain, BY9a.

Modulating acetate ester and higher alcohol production in Saccharomyces cerevisiae through the cofactor engineering.

Flavor production by esters or by higher alcohols play a key role in the sensorial quality of fermented alcoholic beverages. In Saccharomyces cerevisiae cells, the syntheses of esters and higher alcohols are considerably influenced by intracellular CoA levels catalyzed by pantothenate kinase. In this work, we examined the effects of cofactor CoA and acetyl-CoA synthesis on the metabolism of esters and higher alcohols.