Reis Alexandre Libanio Silva, de Fátima Rodrigues de Souza Raquel, Baptista Torres Rochane Regina Neves, Leite Fernanda Cristina Bezerra, Paiva Patrícia Maria Guedes, Vidal Esteban Espinosa, de Morais Marcos Antonio
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.
Interdepartmental Research Group on Metabolic Engineering, Federal University of Pernambuco, 50670-901 Recife, PE, Brazil.
Springerplus. 2014 Jan 20;3:38. doi: 10.1186/2193-1801-3-38. eCollection 2014.
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.
发现一种具有从木质纤维素底物生产乙醇（第二代乙醇）天然能力的新型酵母对生物乙醇技术具有重要意义。虽然有一些酵母菌株能够在需氧实验室条件下同化纤维二糖，而纤维二糖是处理木质纤维素材料中的主要糖类，但对于其在实际工业条件下的这种能力却知之甚少。为了进一步表征从巴西生物乙醇生产过程中分离出的一种有前景的布鲁塞尔德克酵母菌株的发酵能力，在以葡萄糖、蔗糖、纤维二糖和水解预处理甘蔗渣作为不同碳源的合成培养基中进行了模拟工业条件的发酵。结果发现（首次在限氧条件下）布鲁塞尔德克酵母菌株GDB 248能够从纤维二糖生产乙醇。此外，还证实纤维二糖酶活性表征了半纯化提取物中的候选酶（β - 葡萄糖苷酶）。另外，还证明GDB 248菌株产生的乙酸浓度高于乙醇和甘油，这证实了该菌株在限氧条件下不存在库斯特效应。此外，还表明布鲁塞尔德克酵母可能对酿酒酵母有益，并且在工业环境中能胜过酿酒酵母。通过这种方式，证实了布鲁塞尔德克酵母GDB 248具有从纤维二糖生产乙醇 的潜力，是用于木质纤维素底物发酵的一种有前景的菌株。
