Genome sequence of Acremonium strictum AAJ6 strain isolated from the Cerrado biome in Brazil and CAZymes expression in thermotolerant industrial yeast for ethanol production

• Published in: Process biochemistry (1991) 2020-11, Vol.98, p.139-150
• Main Authors: Lopes, Alberto Moura Mendes, Félix de Mélo, Allan Henrique, Procópio, Dielle Pierroti, Teixeira, Gleidson Silva, Carazzolle, Marcelo F., de Carvalho, Lucas Miguel, Adelantado, Núria, Pereira, Gonçalo A.G., Ferrer, Pau, Filho, Francisco Maugeri, Goldbeck, Rosana
• Format: Article
• Language: English
• Subjects: Acremonium strictum; Acremonium strictum genome sequence; Bagasse; Bioethanol; Biofuels; Cassettes; Cellobiase; Cellobiose; Cellulolytic and ligninolytic enzymes; Degradation; Enzymes; Ethanol; Fungi; Gene sequencing; Genomes; Glucosidase; Glycosidases; Glycoside hydrolase; Hydrolase; Industrial strains; Lignocellulose; Nucleotide sequence; Plant debris; Substrates; Sugarcane; Superhigh frequencies; Temperature tolerance; Thermotolerant yeast; Tropical savanna; Whole genome sequencing; Yeasts; β-Glucosidase
• ISSN: 1359-5113; 1873-3298
• DOI: 10.1016/j.procbio.2020.07.029

[Display omitted] •Acreminum strictum AAJ6 isolated from the Cerrado biome in Brazil.•AAJ6 genome showed 380 carbohydrate-active enzyme domains predicted to be secreted.•Expression of GH74 and GH3 in thermotolerant Saccharomyces cerevisiae strains.•Genome-integration in thermotolerant industrial yeast results in higher ethanol.•Reduction in cellulose hydrolysis time gives increased ethanol production. Increased demand for biofuels promotes the search for new biomass-degrading fungi. Acremonium strictum is an environmentally widespread filamentous fungi found on plant debris; that secretes lignocellulose-degrading enzymes. A recently isolated A. strictum strain, AAJ6; native to the Brazilian Cerrado biome was evaluated for its capacity to degrade lignocellulosic substrates. In this study, whole-genome sequencing of AAJ6 was performed and 775 CAZy domains were identified which correlated to those of A. strictum strain DS1bioAY4a and other lignocellulolytic fungi; suggesting AAJ6 is a high CAZyme producer. We expressed the glycoside hydrolase families GH74 and GH3 from plasmid or genome-integrated to evaluate the ethanol production from cellulosic substrates in Brazilian industrial Saccharomyces cerevisiae strains (PE-2 and SA-1) evolved for thermotolerance (AMY12 and AMY35). Those expressing the genome-integrated enzymes showed the highest β-glucosidase activity and growth in medium with cellobiose at 40°C. The strain AGY005 (integrated cassettes) showed 19, 23 and 46% higher ethanol production in SHF, pSSF (partial hydrolysis SSF) and SSF processes, respectively, using Avicel, and ∼50% more ethanol using pre-treated sugarcane bagasse, compared to the strain with a plasmid-based expression. These results indicate the improved performance of thermotolerant industrial strains with genome-integrated CAZymes in the SSF process for 2G ethanol.