44 research outputs found
Consolidated bioprocessing of corn cob-derived hemicellulose: engineered industrial Saccharomyces cerevisiae as efficient whole cell biocatalysts
Background
Consolidated bioprocessing, which combines saccharolytic and fermentative abilities in a single microorganism, is receiving increased attention to decrease environmental and economic costs in lignocellulosic biorefineries. Nevertheless, the economic viability of lignocellulosic ethanol is also dependent of an efficient utilization of the hemicellulosic fraction, which contains xylose as a major component in concentrations that can reach up to 40% of the total biomass in hardwoods and agricultural residues. This major bottleneck is mainly due to the necessity of chemical/enzymatic treatments to hydrolyze hemicellulose into fermentable sugars and to the fact that xylose is not readily consumed by Saccharomyces cerevisiaethe most used organism for large-scale ethanol production. In this work, industrial S. cerevisiae strains, presenting robust traits such as thermotolerance and improved resistance to inhibitors, were evaluated as hosts for the cell-surface display of hemicellulolytic enzymes and optimized xylose assimilation, aiming at the development of whole-cell biocatalysts for consolidated bioprocessing of corn cob-derived hemicellulose.
Results
These modifications allowed the direct production of ethanol from non-detoxified hemicellulosic liquor obtained by hydrothermal pretreatment of corn cob, reaching an ethanol titer of 11.1 g/L corresponding to a yield of 0.328 g/g of potential xylose and glucose, without the need for external hydrolytic catalysts. Also, consolidated bioprocessing of pretreated corn cob was found to be more efficient for hemicellulosic ethanol production than simultaneous saccharification and fermentation with addition of commercial hemicellulases.
Conclusions
These results show the potential of industrial S. cerevisiae strains for the design of whole-cell biocatalysts and paves the way for the development of more efficient consolidated bioprocesses for lignocellulosic biomass valorization, further decreasing environmental and economic costs.This work has been carried out at the Biomass and Bioenergy Research Infrastructure (BBRI)-LISBOA-01-0145-FEDER-022059, supported by Operational
Programme for Competitiveness and Internationalization (PORTUGAL2020),
by Lisbon Portugal Regional Operational Programme (Lisboa 2020) and
by North Portugal Regional Operational Programme (Norte 2020) under the Portugal 2020 Partnership Agreement, through the European Regional
Development Fund (ERDF) and has been supported by the Portuguese
Foundation for Science and Technology (FCT) under the scope of the strategic
funding of UIDB/04469/2020, the “Contrato-Programa” UIDB/04050/2020, the
MIT-Portugal Program (Ph.D. Grant PD/BD/128247/2016 to Joana T. Cunha)
and through Project FatVal (POCI-01-0145-FEDER-032506) and BioTecNorte
operation (NORTE-01-0145-FEDER-000004) funded by the European Regional
Development Fund under the scope of Norte2020 - Programa Operacional
Regional do Norte.info:eu-repo/semantics/publishedVersio
Prediction of GCRV virus-host protein interactome based on structural motif-domain interactions
A single gene encodes isopentenyl diphosphate isomerase isoforms targeted to plastids, mitochondria and peroxisomes in Catharanthus roseus
Vacuole-Targeted Proteins: Ins and Outs of Subcellular Localization Studies
International audienceAccurate and efficient demonstrations of protein localizations to the vacuole or tonoplast remain strict prerequisites to decipher the role of vacuoles in the whole plant cell biology and notably in defence processes. In this chapter, we describe a reliable procedure of protein subcellular localization study through transient transformations of Catharanthus roseus or onion cells and expression of fusions with fluorescent proteins allowing minimizing artefacts of targeting
Characterization of a second secologanin synthase isoform producing both secologanin and secoxyloganin allows enhanced de novo assembly of a Catharanthus roseus transcriptome
Sarpagan bridge enzyme has substrate-controlled cyclization and aromatization modes
International audienceCyclization reactions that create complex polycyclic scaffolds are hallmarks of alkaloid biosynthetic pathways. We present the discovery of three homologous cytochrome P450s from three monoterpene indole alkaloid-producing plants (Rauwolfia serpentina, Gelsemium sempervirens and Catharanthus roseus) that provide entry into two distinct alkaloid classes, the sarpagans and the β-carbolines. Our results highlight how a common enzymatic mechanism, guided by related but structurally distinct substrates, leads to either cyclization or aromatization