Hybridization and adaptive evolution of diverse Saccharomyces species for cellulosic biofuel production

Biotechnology for Biofuels

Trey K. Sato¹  Jean-Baptiste Leducq²  Justin C. Fay³  Katie E. Hyma³  Guillaume Charron⁴  Christian R. Landry⁴  Diego Libkind⁵  Quinn K. Langdon⁶  Qi-Ming Wang⁶  David Peris⁶  William G. Alexander⁶  EmilyClare Baker⁶  Ryan V. Moriarty⁶  Chris Todd Hittinger⁶  Maria Sardi⁶  Kayla Sylvester⁶  Feng-Yan Bai⁷  José Paulo Sampaio⁸  Paula Gonçalves⁸ 

[1] DOE Great Lakes Bioenergy Research Center, University of Wisconsin-Madison;Departement des Sciences Biologiques, Université de Montréal;Department of Genetics, Center for Genome Sciences and Systems Biology, Washington University in St. Louis;Département de Biologie, PROTEO, Pavillon Charles-Eugène-Marchand, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval;Laboratorio de Microbiología Aplicada, Biotecnología y Bioinformática, Instituto Andino Patagónico de Tecnologías Biológicas y Geoambientales, IPATEC (CONICET-UNComahue), Centro Regional Universitario Bariloche;Laboratory of Genetics, Wisconsin Energy Institute, J. F. Crow Institute for the Study of Evolution, Genome Center of Wisconsin, University of Wisconsin-Madison;State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences;UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa;

关键词: Saccharomyces;    Biodiversity;    Ammonia fiber expansion (AFEX);    AFEX-pretreated corn stover hydrolysate (ACSH);    Hybridization;    Bioethanol;   

DOI  :  10.1186/s13068-017-0763-7

来源: DOAJ

【 摘 要 】

Abstract Background Lignocellulosic biomass is a common resource across the globe, and its fermentation offers a promising option for generating renewable liquid transportation fuels. The deconstruction of lignocellulosic biomass releases sugars that can be fermented by microbes, but these processes also produce fermentation inhibitors, such as aromatic acids and aldehydes. Several research projects have investigated lignocellulosic biomass fermentation by the baker’s yeast Saccharomyces cerevisiae. Most projects have taken synthetic biological approaches or have explored naturally occurring diversity in S. cerevisiae to enhance stress tolerance, xylose consumption, or ethanol production. Despite these efforts, improved strains with new properties are needed. In other industrial processes, such as wine and beer fermentation, interspecies hybrids have combined important traits from multiple species, suggesting that interspecies hybridization may also offer potential for biofuel research. Results To investigate the efficacy of this approach for traits relevant to lignocellulosic biofuel production, we generated synthetic hybrids by crossing engineered xylose-fermenting strains of S. cerevisiae with wild strains from various Saccharomyces species. These interspecies hybrids retained important parental traits, such as xylose consumption and stress tolerance, while displaying intermediate kinetic parameters and, in some cases, heterosis (hybrid vigor). Next, we exposed them to adaptive evolution in ammonia fiber expansion-pretreated corn stover hydrolysate and recovered strains with improved fermentative traits. Genome sequencing showed that the genomes of these evolved synthetic hybrids underwent rearrangements, duplications, and deletions. To determine whether the genus Saccharomyces contains additional untapped potential, we screened a genetically diverse collection of more than 500 wild, non-engineered Saccharomyces isolates and uncovered a wide range of capabilities for traits relevant to cellulosic biofuel production. Notably, Saccharomyces mikatae strains have high innate tolerance to hydrolysate toxins, while some Saccharomyces species have a robust native capacity to consume xylose. Conclusions This research demonstrates that hybridization is a viable method to combine industrially relevant traits from diverse yeast species and that members of the genus Saccharomyces beyond S. cerevisiae may offer advantageous genes and traits of interest to the lignocellulosic biofuel industry.

【 授权许可】

Unknown