Diversity and Physiological Characterization of D-Xylose-Fermenting Yeasts Isolated from the Brazilian Amazonian Forest

Autor(es)

Cadete, Raquel M. ^[1] ; Melo, Monaliza A. ^[1] ; Dussan, Kelly J. ^[2] ; Rodrigues, Rita C. L. B. ^[2] ; Silva, Silvio S. ^[2] ; Zilli, Jerri E. ^[3] ; Vital, Marcos J. S. ^[4] ; Gomes, Fatima C. O. ^[5] ; Lachance, Marc-Andre ^[6] ; Rosa, Carlos A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Minas Gerais, Inst Ciencias Biol, Dept Microbiol, Belo Horizonte, MG - Brazil

^[2] Univ Sao Paulo, Dept Biotecnol, Escola Engn Lorena, Sao Paulo - Brazil

^[3] Embrapa Agrobiol, Rio De Janeiro - Brazil

^[4] Univ Fed Roraima, Dept Biol, Boa Vista - Brazil

^[5] Ctr Fed Educ Tecnol Minas Gerais, Dept Quim, Belo Horizonte, MG - Brazil

^[6] Univ Western Ontario, Dept Biol, London, ON - Canada

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 7, n. 8 AUG 13 2012.
• Citações Web of Science: 43

Resumo

Background: This study is the first to investigate the Brazilian Amazonian Forest to identify new D-xylose-fermenting yeasts that might potentially be used in the production of ethanol from sugarcane bagasse hemicellulosic hydrolysates. Methodology/Principal Findings: A total of 224 yeast strains were isolated from rotting wood samples collected in two Amazonian forest reserve sites. These samples were cultured in yeast nitrogen base (YNB)-D-xylose or YNB-xylan media. Candida tropicalis, Asterotremella humicola, Candida boidinii and Debaryomyces hansenii were the most frequently isolated yeasts. Among D-xylose-fermenting yeasts, six strains of Spathaspora passalidarum, two of Scheffersomyces stipitis, and representatives of five new species were identified. The new species included Candida amazonensis of the Scheffersomyces clade and Spathaspora sp. 1, Spathaspora sp. 2, Spathaspora sp. 3, and Candida sp. 1 of the Spathaspora clade. In fermentation assays using D-xylose (50 g/L) culture medium, S. passalidarum strains showed the highest ethanol yields (0.31 g/g to 0.37 g/g) and productivities (0.62 g/L.h to 0.75 g/L.h). Candida amazonensis exhibited a virtually complete D-xylose consumption and the highest xylitol yields (0.55 g/g to 0.59 g/g), with concentrations up to 25.2 g/L. The new Spathaspora species produced ethanol and/or xylitol in different concentrations as the main fermentation products. In sugarcane bagasse hemicellulosic fermentation assays, S. stipitis UFMG-XMD-15.2 generated the highest ethanol yield (0.34 g/g) and productivity (0.2 g/L.h), while the new species Spathaspora sp. 1 UFMG-XMD-16.2 and Spathaspora sp. 2 UFMG-XMD-23.2 were very good xylitol producers. Conclusions/Significance: This study demonstrates the promise of using new D-xylose-fermenting yeast strains from the Brazilian Amazonian Forest for ethanol or xylitol production from sugarcane bagasse hemicellulosic hydrolysates. (AU)

• Processo FAPESP: 08/57926-4 - Etanol: pesquisa e desenvolvimento visando ao aproveitamento integrado do bagaço de cana-de-açúcar para a produção biotecnológica do etanol lignocelulósico
• Beneficiário: Silvio Silvério da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Temático