Expression of Aspergillus niger CAZymes is determined by compositional changes in wheat straw generated by hydrothermal or ionic liquid pretreatments.
Expression of Aspergillus niger CAZymes is determined by compositional changes in wheat straw generated by hydrothermal or ionic liquid pretreatments.
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DOI：
10.1186/s13068-017-0700-9
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发表时间：
2017
影响因子：
6.3
通讯作者：
Archer DB
中科院分区：
文献类型：
--
作者：
Daly P;van Munster JM;Blythe MJ;Ibbett R;Kokolski M;Gaddipati S;Lindquist E;Singan VR;Barry KW;Lipzen A;Ngan CY;Petzold CJ;Chan LJG;Pullan ST;Delmas S;Waldron PR;Grigoriev IV;Tucker GA;Simmons BA;Archer DB
生物技术利用真菌（如尼日尔曲霉）降解木质纤维素的能力，从可再生原料中生产生物燃料和高价值化合物。目前大多数原料都经过预处理以提高酶消化率：提高我们对真菌对预处理木质纤维素底物的转录组学反应的理解，可能有助于改善活性组合并降低商业木质纤维素糖化鸡尾酒的生产成本。我们调查了A.尼日尔与未处理的、离子液体和水热预处理的小麦秸秆在5天的时间过程中使用RNA-seq和靶向蛋白质组学。离子液体预处理改变了纤维素结晶度，同时保留了比水热预处理更多的半纤维素糖。离子液体预处理秸秆导致基因的动态诱导和阻遏，这与离子液体预处理秸秆糖化的戊糖水平较高相关。水热预处理的秸秆导致的碳水化合物活性酶编码基因的转录水平降低，以及衍生的蛋白质和酶的活性。这两种预处理废除了一个大的一组基因编码的果胶分解酶的表达。这些降低的水平可以通过水热预处理去除部分木质纤维素来解释。时间过程也有利于识别时间有限的基因诱导模式。所提出的转录组学和生物化学数据集表明，预处理引起木质纤维素的修饰，对特定的结构特征以及整体木质纤维素结构的组织，这决定了A.尼日尔转录水平。该实验装置允许可靠地检测底物特异性基因表达模式以及迄今未表达的基因。我们的数据表明使用未处理的和IL-预处理的秸秆，而不是HT-预处理的秸秆，作为CAZyme生产的原料的有益效果。本文的在线版本（doi：10.1186/s13068-017-0700-9）包含补充材料，可供授权用户使用。
The capacity of fungi, such as Aspergillus niger, to degrade lignocellulose is harnessed in biotechnology to generate biofuels and high-value compounds from renewable feedstocks. Most feedstocks are currently pretreated to increase enzymatic digestibility: improving our understanding of the transcriptomic responses of fungi to pretreated lignocellulosic substrates could help to improve the mix of activities and reduce the production costs of commercial lignocellulose saccharifying cocktails. We investigated the responses of A. niger to untreated, ionic liquid and hydrothermally pretreated wheat straw over a 5-day time course using RNA-seq and targeted proteomics. The ionic liquid pretreatment altered the cellulose crystallinity while retaining more of the hemicellulosic sugars than the hydrothermal pretreatment. Ionic liquid pretreatment of straw led to a dynamic induction and repression of genes, which was correlated with the higher levels of pentose sugars saccharified from the ionic liquid-pretreated straw. Hydrothermal pretreatment of straw led to reduced levels of transcripts of genes encoding carbohydrate-active enzymes as well as the derived proteins and enzyme activities. Both pretreatments abolished the expression of a large set of genes encoding pectinolytic enzymes. These reduced levels could be explained by the removal of parts of the lignocellulose by the hydrothermal pretreatment. The time course also facilitated identification of temporally limited gene induction patterns. The presented transcriptomic and biochemical datasets demonstrate that pretreatments caused modifications of the lignocellulose, to both specific structural features as well as the organisation of the overall lignocellulosic structure, that determined A. niger transcript levels. The experimental setup allowed reliable detection of substrate-specific gene expression patterns as well as hitherto non-expressed genes. Our data suggest beneficial effects of using untreated and IL-pretreated straw, but not HT-pretreated straw, as feedstock for CAZyme production. The online version of this article (doi:10.1186/s13068-017-0700-9) contains supplementary material, which is available to authorized users.