Key Laboratory for Leather Chemistry and Engineering, Ministry of Education, College of Light Industry, Textile and Food Engineering, Sichuan University, Chengdu 610065, PR China.
Bioresour Technol. 2013 Sep;143:238-41. doi: 10.1016/j.biortech.2013.05.050. Epub 2013 May 21.
The aim of this study was to investigate the effect of nisin-inducible RecO expression on the stress tolerance of Lactococcus lactis NZ9000. RecO protein from Lactobacillus casei Zhang was introduced into Lactococcus lactis NZ9000 by using a nisin-inducible expression system. The recombinant strain (NZ-RecO) exhibited higher growth performances and survival rate compared with the control strain (NZ-Vector) under stress conditions. In addition, the NZ-RecO strain exhibited 1.37-, 1.41-, and 1.42-fold higher biomass, lactate production, lactate productivity, compared with the corresponding values for NZ-Vector during NaCl-stressed condition. Analysis of lactate dehydrogenase (LDH) activity showed that the production of RecO maintained the stability of LDH during salt stress. These results suggest that overproduction of RecO improved the multiple-stress tolerance and lactic acid production in Lactococcus lactis NZ9000 during salt stress. Results presented in this study may help to enhance the industrial utility of lactic acid bacteria.
本研究旨在探讨诱导型 RecO 表达对乳酸乳球菌 NZ9000 应激耐受性的影响。通过使用乳链菌肽诱导表达系统，将来源于干酪乳杆菌 Zhang 的 RecO 蛋白引入到乳酸乳球菌 NZ9000 中。与对照菌株（NZ-Vector）相比，重组菌株（NZ-RecO）在应激条件下表现出更高的生长性能和存活率。此外，在 NaCl 胁迫条件下，NZ-RecO 菌株的生物量、乳酸产量和乳酸比生产力分别比 NZ-Vector 菌株高出 1.37 倍、1.41 倍和 1.42 倍。乳酸脱氢酶（LDH）活性分析表明，RecO 的产生在盐胁迫过程中维持了 LDH 的稳定性。这些结果表明，RecO 的过表达提高了乳酸乳球菌 NZ9000 在盐胁迫下的多重应激耐受性和乳酸产量。本研究结果可能有助于提高乳酸菌的工业实用性。
