Integrated expression of the α-amylase, dextranase and glutathione gene in an industrial brewer's yeast strain.
Genetic engineering is widely used to meliorate biological characteristics of industrial brewing yeast. But how to solve multiple problems at one time has become the bottle neck in the genetic modifications of industrial yeast strains. In a newly constructed strain TYRL21, dextranase gene was expressed in addition of α-amylase to make up α-amylase's shortcoming which can only hydrolyze α-1,4-glycosidic bond. Meanwhile, 18s rDNA repeated sequence was used as the homologous sequence for an effective and stable expression of LSD1 gene. As a result, TYRL21 consumed about twice much starch than the host strain. Moreover TYRL21 speeded up the fermentation which achieved the maximum cell number only within 3 days during EBC tube fermentation. Besides, flavor evaluation comparing TYRL21 and wild type brewing strain Y31 also confirmed TYRL21's better performances regarding its better saccharides utilization (83% less in residual saccharides), less off-flavor compounds (57% less in diacetyl, 39% less in acetaldehyde, 67% less in pentanedione), and improved stability index (increased by 49%) which correlated with sensory evaluation of final beer product.
The Laboratory of Molecular Genetics and Breeding of Yeasts, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
Jin-Jing
JJ
Wang
Zhao-Yue
ZY
Wang
Xiu-Ping
XP
He
Bo-Run
BR
Zhang
D001483:Base Sequence; D001515:Beer / Q000382:microbiology; D002244:Carbon / Q000378:metabolism; D004271:DNA, Fungal / Q000235:genetics; D003910:Dextranase / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D015870:Gene Expression; D005800:Genes, Fungal; D005818:Genetic Engineering; D042822:Genomic Instability; D005978:Glutathione / Q000235:genetics* / Q000378:metabolism; D007218:Industrial Microbiology; D007700:Kinetics; D009154:Mutation; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D000516:alpha-Amylases / Q000235:genetics* / Q000378:metabolism
D004271:DNA, Fungal; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D002244:Carbon; D000516:alpha-Amylases; D003910:Dextranase; D005978:Glutathione