Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av do Café S/N, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Federal de São Carlos, Brazil.
Biotechnol Biofuels. 2011 Oct 18;4:40. doi: 10.1186/1754-6834-4-40.
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).
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.
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.
考虑到纤维素酶和半纤维素酶的成本对生物乙醇的价格有很大的影响，因此，旨在了解和提高纤维素酶效率和生产力的新研究至关重要。黑曲霉已被证明能产生广泛的多糖水解酶。为了了解如何改进能够水解预处理甘蔗渣的酶混合物，我们使用基因组学方法研究了黑曲霉在蒸汽爆破甘蔗渣（SEB）上生长时哪些基因和途径被转录调节。
在此，我们报告了在 SEB 上生长时表达增加的主要纤维素酶和半纤维素酶编码基因。我们还试图确定 SEB 诱导的几个编码假定转运蛋白的基因的 mRNA 积累是否被木糖诱导，并依赖于葡萄糖。我们鉴定了 18 个（黑曲霉预测纤维素酶的 58%）和 21 个（黑曲霉预测半纤维素酶的 58%）纤维素酶和半纤维素酶编码基因，它们在 SEB 上生长时表达水平很高。
甘蔗渣的降解需要产生许多不同的酶，这些酶受可用底物的类型和复杂性调节。我们目前的工作为了解黑曲霉水解酶对甘蔗生物质糖化的作用以及构建更有效的第二代生物乙醇用酶混合物开辟了新的可能性。
