Oxygen-limited cellobiose fermentation and the characterization of the cellobiase of an industrial Dekkera/Brettanomyces bruxellensis strain.
The discovery of a novel yeast with a natural capacity to produce ethanol from lignocellulosic substrates (second-generation ethanol) is of great significance for bioethanol technology. While there are some yeast strains capable of assimilating cellobiose in aerobic laboratory conditions, the predominant sugar in the treatment of lignocellulosic material, little is known about this ability in real industrial conditions. Fermentations designed to simulate industrial conditions were conducted in synthetic medium with glucose, sucrose, cellobiose and hydrolyzed pre-treated cane bagasse as a different carbon source, with the aim of further characterizing the fermentation capacity of a promising Dekkera bruxellensis yeast strain, isolated from the bioethanol process in Brazil. As a result, it was found (for the first time in oxygen-limiting conditions) that the strain Dekkera bruxellensis GDB 248 could produce ethanol from cellobiose. Moreover, it was corroborated that the cellobiase activity characterizes the enzyme candidate in semi-purified extracts (β-glucosidase). In addition, it was demonstrated that GDB 248 strain had the capacity to produce a higher acetic acid concentration than ethanol and glycerol, which confirms the absence of the Custer effect with this strain in oxygen-limiting conditions. Moreover, it is also being suggested that D. bruxellensis could benefit Saccharomyces cerevisiae and outcompete it in the industrial environment. In this way, it was confirmed that D. bruxellensis GDB 248 has the potential to produce ethanol from cellobiose, and is a promising strain for the fermentation of lignocellulosic substrates.
Bioprocessing Laboratory, CETENE, 50740-540 Recife, PE, Brazil ; Centro de Tecnologias Estratégicas do Nordeste - CETENE, Av. Prof. Luiz Freire, 01, Cidade Universitária, 50740-540 Recife, PE, Brasil.
Alexandre Libanio Silva
AL
Reis
Interdepartmental Research Group on Metabolic Engineering, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Raquel
R
de Fátima Rodrigues de Souza
Interdepartmental Research Group on Metabolic Engineering, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Rochane Regina Neves
RR
Baptista Torres
Interdepartmental Research Group on Metabolic Engineering, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Fernanda Cristina Bezerra
FC
Leite
Department of Genetics, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Patrícia Maria Guedes
PM
Paiva
Bioprocessing Laboratory, CETENE, 50740-540 Recife, PE, Brazil.
Esteban Espinosa
EE
Vidal
Bioprocessing Laboratory, CETENE, 50740-540 Recife, PE, Brazil ; Interdepartmental Research Group on Metabolic Engineering, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil ; Department of Genetics, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil ; Department of Biochemistry, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Marcos Antonio
MA
de Morais
BGL gene; Hydrolyzed bagasse; Lignocellulose; β-glucosidase