Repeated batches as a strategy for high 2G ethanol production from undetoxified hemicellulose hydrolysate using immobilized cells of recombinant Saccharomyces cerevisiae in a fixed-bed reactor

Author(s)

Milessi, Thais S. ^{[1, 2]} ; Perez, Caroline L. ^[3] ; Zangirolami, Teresa C. ^{[1, 3]} ; Corradini, Felipe A. S. ^[3] ; Sandri, Juliana P. ^[3] ; Foulquie-Moreno, Maria R. ^{[4, 5]} ; Giordano, Roberto C. ^{[1, 3]} ; Thevelein, Johan M. ^{[4, 5]} ; Giordano, Raquel L. C. ^{[1, 3]}

Affiliation

^[1] Univ Fed Sao Carlos, Dept Chem Engn, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[2] Univ Fed Itajuba, Inst Nat Resources, Av Benedito Pereira Santos 1303, BR-37500903 Itajuba, MG - Brazil

^[3] Fed Univ Sao Carlos PPGEQ UFSCar, Grad Program Chem Engn, Rodovia Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] Katholieke Univ Leuven, Lab Mol Cell Biol, Inst Bot & Microbiol, Kasteelpk Arenberg 31, B-3001 Leuven, Flanders - Belgium

^[5] VIB, Ctr Microbiol, Kasteelpk Arenberg 31, B-3001 Leuven, Flanders - Belgium

• Document type: Journal article
• Source: BIOTECHNOLOGY FOR BIOFUELS; v. 13, n. 1 MAY 11 2020.
• Web of Science Citations: 0

Abstract

Background The search for sustainable energy sources has become a worldwide issue, making the development of efficient biofuel production processes a priority. Immobilization of second-generation (2G) xylose-fermenting Saccharomyces cerevisiae strains is a promising approach to achieve economic viability of 2G bioethanol production from undetoxified hydrolysates through operation at high cell load and mitigation of inhibitor toxicity. In addition, the use of a fixed-bed reactor can contribute to establish an efficient process because of its distinct advantages, such as high conversion rate per weight of biocatalyst and reuse of biocatalyst. Results This work assessed the influence of alginate entrapment on the tolerance of recombinant S. cerevisiae to acetic acid. Encapsulated GSE16-T18SI.1 (T18) yeast showed an outstanding performance in repeated batch fermentations with cell recycling in YPX medium supplemented with 8 g/L acetic acid (pH 5.2), achieving 10 cycles without significant loss of productivity. In the fixed-bed bioreactor, a high xylose fermentation rate with ethanol yield and productivity values of 0.38 g(ethanol)/g(sugars) and 5.7 g/L/h, respectively were achieved in fermentations using undetoxified sugarcane bagasse hemicellulose hydrolysate, with and without medium recirculation. Conclusions The performance of recombinant strains developed for 2G ethanol production can be boosted strongly by cell immobilization in alginate gels. Yeast encapsulation allows conducting fermentations in repeated batch mode in fixed-bed bioreactors with high xylose assimilation rate and high ethanol productivity using undetoxified hemicellulose hydrolysate. (AU)

• FAPESP's process: 16/10636-8 - From the cell factory to the Biodiesel-Bioethanol integrated biorefinery: a systems approach applied to complex problems in micro and macroscales
• Grantee: Roberto de Campos Giordano
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants