The application of enzymes for sustainable and low-environmental impact industrial processes requires high-level enzyme production at low-cost. A promising strategy is the use of a high efficiency heterologous protein expression system using E. coli and the pT7BsXA vector encoding the GH11 xylanase from Bacillus subtilis with promoter, replication origin and signal peptide sequences from B. subtilis (Ruller et al. 2006). This expression system produces high amounts of enzyme that are secreted to the culture broth. The present study aimed to maximize the xylanase production by this system through evaluation of culture medium composition. Different culture media previously described in the literature together with compositions derived from agro-industrial residues were evaluated. A culture medium derived from agro-industrial residues using sugarcane molasses as carbon source showed a 9-fold increase in enzyme production (195,000 U/L) in relation to LB medium and the lowest production cost, which was 8.5-fold lower than LB medium using sugarcane molasses as carbon source and brewer’s yeast as vitamin source in shaker experiments. In a bioreactor experiment the best production medium promoted an 8.5-fold higher production at a 10.8-fold lower cost as compared to shaker LB cultivation.

中文翻译：

---

使用具有不同营养来源的非诱导表达系统由大肠杆菌生产重组木聚糖酶

酶在可持续和低环境影响的工业过程中的应用需要以低成本生产高水平的酶。一个有前景的策略是使用高效异源蛋白质表达系统，该系统使用大肠杆菌和 pT7BsXA 载体编码来自枯草芽孢杆菌的 GH11 木聚糖酶，以及来自枯草芽孢杆菌的启动子、复制起点和信号肽序列（Ruller 等人，2006 年）。该表达系统产生大量分泌到培养液中的酶。本研究旨在通过评估培养基组成来最大限度地提高该系统的木聚糖酶产量。对先前在文献中描述的不同培养基以及源自农业工业残留物的组合物进行了评估。以甘蔗糖蜜为碳源的农业工业残留物培养基与 LB 培养基相比，酶产量增加了 9 倍（195,000 U/L），生产成本最低，比 LB 培养基低 8.5 倍在摇床实验中使用甘蔗糖蜜作为碳源和啤酒酵母作为维生素源。在生物反应器实验中，与振动筛 LB 培养相比，最佳生产培养基以 10.8 倍的成本降低了 8.5 倍的产量。