Fu Rui-Yan, Chen Jian, Li Yin
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Southern Yangtze University, Wuxi 214036, People's Republic of China.
Appl Environ Microbiol. 2005 Dec;71(12):8911-9. doi: 10.1128/AEM.71.12.8911-8919.2005.
This study describes a novel strategy to improve the growth performance of Lactococcus lactis by heterologous production of food-grade transglutaminase. The mtg gene from Streptoverticillium mobaraense that encodes the transglutaminase mature protein was cloned into a nisin-inducible expression vector and transformed into L. lactis subsp. cremoris NZ9000. The leaky expression of the mtg gene from the nisA promoter resulted in ammonia formation and carbon flux redistribution at the pyruvate branch. As a consequence, medium acidification was lessened and energy utilization was improved. This led to significantly higher biomass production under aerobic conditions and particularly under non-pH-controlled conditions (up to a 12-fold increase). The results presented here provide a novel way to enhance the growth yield of L. lactis, which is an important step for the purposes of producing proteins of commercial interest using L. lactis as a host.
本研究描述了一种通过异源生产食品级转谷氨酰胺酶来提高乳酸乳球菌生长性能的新策略。将来自茂原链霉菌的编码转谷氨酰胺酶成熟蛋白的mtg基因克隆到一种乳酸链球菌素诱导型表达载体中，并转化到乳酸乳球菌乳脂亚种NZ9000中。来自nisA启动子的mtg基因的渗漏表达导致丙酮酸分支处氨的形成和碳通量重新分布。结果，培养基酸化减轻，能量利用得到改善。这导致在有氧条件下，特别是在非pH控制条件下生物量产量显著提高（高达12倍）。此处呈现的结果提供了一种提高乳酸乳球菌生长产量的新方法，这是利用乳酸乳球菌作为宿主生产具有商业价值蛋白质的重要一步。
