Transcriptome analysis of Aspergillus niger grown on sugarcane bagasse.
BACKGROUND
Considering that the costs of cellulases and hemicellulases contribute substantially to the price of bioethanol, new studies aimed at understanding and improving cellulase efficiency and productivity are of paramount importance. Aspergillus niger has been shown to produce a wide spectrum of polysaccharide hydrolytic enzymes. To understand how to improve enzymatic cocktails that can hydrolyze pretreated sugarcane bagasse, we used a genomics approach to investigate which genes and pathways are transcriptionally modulated during growth of A. niger on steam-exploded sugarcane bagasse (SEB).


RESULTS
Herein we report the main cellulase- and hemicellulase-encoding genes with increased expression during growth on SEB. We also sought to determine whether the mRNA accumulation of several SEB-induced genes encoding putative transporters is induced by xylose and dependent on glucose. We identified 18 (58% of A. niger predicted cellulases) and 21 (58% of A. niger predicted hemicellulases) cellulase- and hemicellulase-encoding genes, respectively, that were highly expressed during growth on SEB.


CONCLUSIONS
Degradation of sugarcane bagasse requires production of many different enzymes which are regulated by the type and complexity of the available substrate. Our presently reported work opens new possibilities for understanding sugarcane biomass saccharification by A. niger hydrolases and for the construction of more efficient enzymatic cocktails for second-generation bioethanol.
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
Wagner R
WR
de Souza
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
Paula F
PF
de Gouvea
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
Marcela
M
Savoldi
Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de São Carlos, Brazil.
Iran
I
Malavazi
Departamento de Ciências Exatas e Tecnológicas, Universidade Estadual de Santa Cruz, Rodovia Ilhéus-Itabuna, km 16, CEP 45662-000, Ilhéus, Bahia, Brazil.
Luciano A
LA
de Souza Bernardes
Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Avenida dos Bandeirantes, 3900, CEP 14040-901, Ribeirão Preto, São Paulo, Brazil.
Maria Helena S
MHS
Goldman
CBS-KNAW Fungal Biodiversity Centre, Uppsalalaan 8, 3584 CT, Utrecht, The Netherlands.
Ronald P
RP
de Vries
Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Caixa Postal 6170, 13083-970 Campinas, São Paulo, Brazil.
Juliana V
JV
de Castro Oliveira
Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.|Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Caixa Postal 6170, 13083-970 Campinas, São Paulo, Brazil.
Gustavo H
GH
Goldman