Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering, University of Minho, Braga, Portugal.
Bioprocess Biosyst Eng. 2012 Sep;35(7):1185-92. doi: 10.1007/s00449-012-0705-5. Epub 2012 Feb 26.
Agroindustrial residues are materials often rich in cellulose and hemicellulose. The use of these substrates for the microbial production of enzymes of industrial interest is mainly due to their high availability associated with their low cost. In this work, corncob (CCs) particles decomposed to soluble compounds (liquor) were incorporated in the microbial growth medium through autohydrolysis, as a strategy to increase and undervalue xylanase and β-xylosidase production by Aspergillus terricola and Aspergillus ochraceus. The CCs autohydrolysis liquor produced at 200 °C for 5, 15, 30 or 50 min was used as the sole carbon source or associated with untreated CC. The best condition for enzyme synthesis was observed with CCs submitted to 30 min of autohydrolysis. The enzymatic production with untreated CCs plus CC liquor was higher than with birchwood xylan for both microorganisms. A. terricola produced 750 total U of xylanase (144 h cultivation) and 30 total U of β-xylosidase (96-168 h) with 0.75% untreated CCs and 6% CCs liquor, against 650 total U of xylanase and 2 total U of β-xylosidase in xylan; A. ochraceus produced 605 total U of xylanase and 56 total U of β-xylosidase (168 h cultivation) with 1% untreated CCs and 10% CCs liquor against 400 total U of xylanase and 38 total U of β-xylosidase in xylan. These results indicate that the treatment of agroindustrial wastes through autohydrolysis can be a viable strategy in the production of high levels of xylanolytic enzymes.
农业工业废料通常富含纤维素和半纤维素。这些基质被用于微生物生产具有工业应用价值的酶，主要是因为它们的高可用性和低成本。在这项工作中，玉米芯（CCs）颗粒通过自水解分解为可溶化合物（水解液），并作为一种策略被添加到微生物生长培养基中，以提高和低估土曲霉和杂色曲霉产生的木聚糖酶和β-木糖苷酶的产量。在 200°C 下自水解 5、15、30 或 50 分钟产生的 CCs 水解液被用作唯一的碳源或与未处理的 CCs 一起使用。对于酶的合成，观察到 CCs 经过 30 分钟的自水解达到最佳条件。对于未经处理的 CCs 加上 CCs 水解液的酶生产，对于两种微生物都高于桦木木聚糖。土曲霉在 0.75%未经处理的 CCs 和 6% CCs 水解液中产生 750 总 U 的木聚糖酶（144 h 培养）和 30 总 U 的β-木糖苷酶（96-168 h），而在木聚糖中产生 650 总 U 的木聚糖酶和 2 总 U 的β-木糖苷酶；杂色曲霉在 1%未经处理的 CCs 和 10% CCs 水解液中产生 605 总 U 的木聚糖酶和 56 总 U 的β-木糖苷酶（168 h 培养），而在木聚糖中产生 400 总 U 的木聚糖酶和 38 总 U 的β-木糖苷酶。这些结果表明，通过自水解处理农业工业废物是生产高水平木聚糖酶的可行策略。
