PDF(Pubmed)
Abstract：
The β-fructofuranosidase enzyme from Aspergillus niger has been extensively used to commercially produce fructooligosaccharides from sucrose. In this study, the native and an engineered version of the β-fructofuranosidase enzyme were expressed in Pichia pastoris under control of the glyceraldehyde-3-phosphate dehydrogenase promoter, and production was evaluated in bioreactors using either dissolved oxygen (DO-stat) or constant feed fed-batch feeding strategies. The DO-stat cultivations produced lower biomass concentrations but this resulted in higher volumetric activity for both strains. The native enzyme produced the highest volumetric enzyme activity for both feeding strategies (20.8% and 13.5% higher than that achieved by the engineered enzyme, for DO-stat and constant feed, respectively). However, the constant feed cultivations produced higher biomass concentrations and higher volumetric productivity for both the native as well as engineered enzymes due to shorter process time requirements (59 h for constant feed and 155 h for DO-stat feed). Despite the DO-stat feeding strategy achieving a higher maximum enzyme activity, the constant feed strategy would be preferred for production of the β-fructofuranosidase enzyme using glycerol due to the many industrial advantages related to its enhanced volumetric enzyme productivity.
摘要：
来自黑曲霉的β-呋喃果糖苷酶已被广泛用于从蔗糖商业生产低聚果糖。在这项研究中,β-呋喃果糖苷酶的天然和工程版本在3-磷酸甘油醛脱氢酶启动子的控制下在巴斯德毕赤酵母中表达，并使用溶解氧（DO-stat）或恒定进料分批进料策略在生物反应器中评估生产。DO-stat培养产生较低的生物量浓度，但这导致两种菌株的体积活性较高。天然酶在两种喂养策略中都产生了最高的体积酶活性（比工程酶高20.8％和13.5％，对于DO-stat和恒定进料，分别)。然而,由于工艺时间要求较短（恒定饲料为59小时，DO-stat饲料为155小时），恒定的饲料培养对天然酶和工程酶都产生了更高的生物量浓度和更高的体积生产率。尽管DO-stat喂养策略实现了更高的最大酶活性，恒定补料策略对于使用甘油生产β-呋喃果糖苷酶将是优选的,这是由于与其提高的体积酶生产率相关的许多工业优势。
