IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, University of Minho, Campus Gualtar, 4710-057 Braga, Portugal.
Appl Biochem Biotechnol. 2012 Jan;166(2):336-47. doi: 10.1007/s12010-011-9428-3. Epub 2011 Nov 10.
The xylanase biosynthesis is induced by its substrate-xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and β-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.
木聚糖酶的生物合成是由其底物木聚糖诱导的。一些废物（如麦麸和麦秸）中的高木聚糖含量使它们成为可利用的廉价诱导物来源，主要应用于大量发酵，如工业生物反应器中的发酵。因此，在这项工作中，主要建议是将麦秸颗粒分解为可溶化合物（蒸煮液）纳入营养培养基中，通过木质纤维素材料的自水解处理，作为一种增加和低估土曲霉木聚糖酶生产的策略。在几种条件下生产的麦秸自水解蒸煮液被用作唯一的碳源，或与麦麸一起使用。当 A.ochraceus 以 1%的麦麸添加 10%的麦秸蒸煮液（在 15 分钟的湿热处理后生产）作为碳源进行培养时，观察到木聚糖酶和β-木糖苷酶的最佳生产条件。与单独使用木聚糖、麦麸和麦秸自水解液相比，这种底物更有利。将这种底物混合物应用于搅拌罐生物反应器表明，该过程有可能扩大到商业生产。
