Expression of a mutated SPT15 gene in Saccharomyces cerevisiae enhances both cell growth and ethanol production in microaerobic batch, fed-batch, and simultaneous saccharification and fermentations.
The SPT15 gene encodes a Saccharomyces cerevisiae TATA-binding protein, which is able to globally control the transcription levels of various metabolic and regulatory genes. In this study, a SPT15 gene mutant (S42N, S78R, S163P, and I212N) was expressed in S. cerevisiae BY4741 (BSPT15-M3), of which effects on fermentative yeast properties were evaluated in a series of culture types. By applying different nitrogen sources and air supply conditions in batch culture, organic nitrogen sources and microaerobic condition were decided to be more favorable for both cell growth and ethanol production of the BSPT15-M3 strain than the control S. cerevisiae BY4741 strain expressing the SPT15 gene (BSPT15wt). Microaerobic fed-batch cultures of BSPT15-M3 with glucose shock in the presence of high ethanol content resulted in a 9.5-13.4% higher glucose consumption rate and ethanol productivity than those for the BSPT15wt strain. In addition, BSPT15-M3 showed 4.5 and 3.9% increases in ethanol productivity from cassava hydrolysates and corn starch in simultaneous saccharification and fermentation processes, respectively. It was concluded that overexpression of the mutated SPT15 gene would be a potent strategy to develop robust S. cerevisiae strains with enhanced cell growth and ethanol production abilities.
Department of Bio and Fermentation Convergence Technology, and BK21 PLUS Program, Kookmin University, Seoul, 136-702, South Korea.
Yeong-Je
YJ
Seong
Department of Bio and Fermentation Convergence Technology, and BK21 PLUS Program, Kookmin University, Seoul, 136-702, South Korea.
Haeseong
H
Park
Department of Biotechnology, Graduate School, Korea University, Seoul, 136-713, South Korea.
Jungwoo
J
Yang
Center for Food and Bioconvergence, Seoul National University, Seoul, 151-742, South Korea.
Soo-Jung
SJ
Kim
Department of Life Sciences, College of Natural Sciences, Ewha Womans University, Seoul, 120-750, South Korea.
Wonja
W
Choi
Department of Biotechnology, Graduate School, Korea University, Seoul, 136-713, South Korea.
Kyoung Heon
KH
Kim
Department of Bio and Fermentation Convergence Technology, and BK21 PLUS Program, Kookmin University, Seoul, 136-702, South Korea. ycpark@kookmin.ac.kr.
Yong-Cheol
YC
Park
D000332:Aerobiosis; D000693:Anaerobiosis; D003470:Culture Media / Q000737:chemistry; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D015870:Gene Expression; D002365:Manihot / Q000378:metabolism; D060847:Metabolic Engineering; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism; D035181:TATA-Box Binding Protein / Q000235:genetics / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism
D003470:Culture Media; D050505:Mutant Proteins; C115017:SPT15 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D000431:Ethanol; D013213:Starch; D009584:Nitrogen
Microaerobic fermentation; Osmotic tolerance; SPT15; Saccharomyces cerevisiae; Simultaneous saccharification and fermentation