关键词: 植物乳杆菌；谷氨酰胺；合成酶活力；发酵

Abstract: Lactobacillus plantarum is a probiotic bacterium with various biological effects. Its ability to relieve muscle fatigue and injury has aroused market concerns, which is associated with glutamine synthetase (GS) activity. However, the literature currently lacks reports on the production of GS by fermentation with Lactobacillus plantarum. In this study, the GS activity of L. plantarum Lp-G18 was enhanced by adding L-glutamic acid to the medium and optimizing the carbon sources and metal ion concentrations. The optimized medium was composed of glucose 40 g/L (222 mmol/L), MgSO4·7H2O 4.92 g/L (20 mmol/L), MnSO4 0. 025 g/L (1.5 mmol/L), L-glutamic acid 8.82 g/L (60 mmol/L), peptone 10 g/L, beef extract powder 10 g/L, yeast extract powder 5 g/L, K2HPO4 2 g/L, NaAc 5 g/L, diammonium hydrogen citrate 2 g/L, and Tween-80 1 g/L. The GS activity obtained using the optimized medium was 2.4 times higher than that from basal MRS medium.

Key words: Lactobacillus plantarum; glutamine; synthetase activity; fermentation