通过分批培养系统分析了罗伊氏乳杆菌138-1对21种市售氮源的利用效率,并通过恒pH自动反馈补糖工艺,结合高效液相色谱(high performance liquid chromatography,HPLC)测定了各氮源被罗伊氏乳杆菌138-1利用前后氨基酸和肽的变化,分析了该菌株对氮源种类和肽分子量的利用规律。结果表明,罗伊氏乳杆菌138-1主要利用氮源中低于1 000 Da的小分子肽,且对500 Da以下的小分子肽利用率最高。各氮源中均含有丰富的小分子肽,但该菌株氮利用具有底物特异性,能更有效地利用酵母提取物、酵母蛋白103、酵母浸粉528及酵母浸粉803等酵母类蛋白胨中的小分子肽,对酵母类氮源的利用效率显著高于植物、乳品和动物组织类氮源。
Lactobacillus reuteri is one of the most important probiotics in human body. The nitrogen source is the key factor restricting its fermentation production. The study of types and characteristics of nitrogen sources effectively used by Lactobacillus reuteri will further guide the fermentation. The utilization efficiency of Lactobacillus reuteri 138-1 for 21 kinds of marketable nitrogen sources was analyzed by batch culture system. The changes of amino acids and peptides of each nitrogen source before and after used by Lactobacillus reuteri 138-1 during constant pH and automatic feedback feeding culture were determined by high performance liquid chromatography (HPLC). The types of available nitrogen source and the molecular weight of peptides utilized by the strain were analyzed. Lactobacillus reuteri 138-1 mainly used small peptides with molecular weight below 1 000 Da, and had the highest utilization rate for the peptides below 500 Da. Although all nitrogen sources were rich in small molecular peptides, the nitrogen utilization of the strain had the substrate specificity. The small molecular peptides in yeast peptone such as yeast extract, yeast protein 103, yeast extract 528 and yeast extract 803 were more effectively utilized. The utilization efficiency of yeast nitrogen source was significantly higher than that from plant, dairy and animal tissues.
[1] 庞洁,周娜,刘鹏,等.罗伊氏乳杆菌的益生功能[J].中国生物工程杂志,2011,31(5):131-137.
[2] CHEN Fang-yu,LEE M T, HUANG H W. Sigmoidal concentration dependence of antimicrobial peptide activities: A case study on alamethicin [J]. Biophysical Journal,2002,82(2): 908-914.
[3] PICON A, GARCIA-CASADO M A, NUNEZ M. Proteolytic activities, peptide utilization and oligopeptide transport systems of wild Lactococcus lactis strains[J].International Dairy Journal,2010,20(3):156-162.
[4] HOU Jun-cai,DA Xi,WEI Wei,et al. Effect of culturing conditions on the expression of key enzymes in the proteolytic system of Lactobacillus bulgaricus [J].Zhejiang Univ Sci B,2015,16(4):317-326.
[5] FOUCAUD C, KUNJI E R, HAGTING A, et al. Specificity of peptide transport systems in Lactococcus lactis: evidence for a third system which transports hydrophobic di- and tripeptides[J].Journal of Bacteriology,1995,177(16):4 652-4 657.
[6] 杜越欧,侯俊财.乳酸菌蛋白水解体系及相关基因表达的研究进展[J].食品工业科技,2013,34(3):383-386.
[7] CHRISTENSEN J E, DUDLEY E G, PEDERSON J A,et al.Peptidases and amino acid catabolism in lactic acid bacteria[J].Antonie Van Leeuwenhoek,1999, 76(1-4): 217-246.
[8] MAKAROVA K S, KOONIN E V. Evolutionary genomics of lactic acid bacteria[J]. Journal of Bacteriology,2007,189(4):1 199-1 208.
[9] 崔树茂.乳酸菌的生长抑制和冻干存活的影响因素及规律[D].无锡:江南大学,2017.
[10] LIU Bo-yu, ZHU Ke-xue, PENG Wei,et al.Effect of sequential hydrolysis with endo-and exo-peptidase on bitterness properties of wheat gluten hydrolysates[J]. RSC Advances,2016,6(33):27 659-27 668.
[11] KLAENHAMMER T R, BARRANGOU R, BUCK B L,et al.Genomic features of lactic acid bacteria effecting bioprocessing and health[J].FEMS Microbiology Reviews,2005,29(3):393-409.
[12] WU Chong-de, HUANG Jun, ZHOU Rong-qing.Genomics of lactic acid bacteria: Current status and potential applications[J].Critical Reviews in Microbiology,2017, 43 (4): 393-404.
[13] 张一爽,曲晓军,崔艳华.发酵乳中乳酸菌产生的风味物质[J].中国乳品工业,2017,45(10):28-32.
[14] CHRISTENSEN J E, STEELE J L.Impaired growth rates in milk of Lactobacillus helveticus peptidase mutants can be overcome by use of amino acid supplements[J].Journal of Bacteriology,2003,185(11):3 297-3 306.
[15] MIERAU I, KUNJI E R, LEENHOUTS K J,et al. Multiple-peptidase mutants of Lactococcus lactis are severely impaired in their ability to grow in milk[J]. Journal of Bacteriology,1996,178(10):2 794-2 803.
[16] LIU Ming-jin, BAYJANOV J R, RENCKENS B,et al.The proteolytic system of lactic acid bacteria revisited: a genomic comparison[J].Bmc Genomics, 2010,11 (1):36-51.