PDF(Pubmed)
Abstract：
Mannan, a highly abundant and cost-effective natural resource, holds great potential for the generation of high-value compounds such as bioactive polysaccharides and biofuels. In this study, we successfully enhanced the expression of constructed GH5 β-mannanase (TaMan5) from Trichoderma asperellum ND-1 by employing propeptide in Pichia pastoris. By replacing the α-factor with propeptide (MGNRALNSMKFFKSQALALLAATSAVA), TaMan5 activity was significantly increased from 67.5 to 91.7 U/mL. It retained higher activity in the presence of 20% ethanol and 15% NaCl. When incubated with a high concentration of mannotriose or mannotetraose, the transglycosylation action of TaMan5 can be detected, yielding the corresponding production of mannotetraose or mannooligosaccharides. Moreover, the unique mechanism whereby TaMan5 catalyzes the degradation of mannan into mannobiose involves the transglycosylation of mannose to mannotriose or mannotetraose as a substrate to produce a mannotetraose or mannopentose intermediate, respectively. Additionally, the production of soluble sugars from lignocellulose is a crucial step in bioethanol development, and it is noteworthy that TaMan5 could synergistically yield fermentable sugars from corn stover and bagasse. These findings offered valuable insights and strategies for enhancing β-mannanase expression and efficient conversion of lignocellulosic biomass, providing cost-effective and sustainable approaches for high-value biomolecule and biofuel production.
摘要：
Mannan,一种非常丰富和具有成本效益的自然资源，具有产生高价值化合物如生物活性多糖和生物燃料的巨大潜力。在这项研究中,通过在毕赤酵母中使用前肽，我们成功地增强了构建的GH5β-甘露聚糖酶（TaMan5）的表达。通过用前肽（MGNRALNSMKFFKSQALALLAATSAVA）代替α因子，TaMan5活性从67.5U/mL显著增加至91.7U/mL。在20％乙醇和15％NaCl的存在下，它保留了更高的活性。当与高浓度的甘露糖或甘露糖孵育时，可以检测到TaMan5的转糖基化作用，产生相应的甘露糖或甘露寡糖的生产。此外，TaMan5催化甘露聚糖降解为甘露二糖的独特机制涉及甘露糖转糖基化为甘露糖或甘露糖作为底物以产生甘露糖或甘露戊糖中间体，分别。此外,从木质纤维素中生产可溶性糖是生物乙醇开发的关键步骤，值得注意的是，TaMan5可以从玉米秸秆和甘蔗渣中协同生产可发酵糖。这些发现为增强木质纤维素生物质的β-甘露聚糖酶表达和有效转化提供了有价值的见解和策略。为高价值生物分子和生物燃料生产提供具有成本效益和可持续的方法。
