Effects of NaCl on the Transcription of Genes Involved in AGDI and Putrescine Production of Lactobacillus delbrueckii

The study explored the effects of different concentrations of NaCl on Lactobacillus delbrueckii which could produce putrescine by AGDI pathway. Reverse transcription quantitative polymerase chain reaction(RT-qPCR)technique was used to analyze the related gene expression. Ultra performance liquid chromatography(UPLC)was used to monitor putrescine produced by Lactobacillus delbrueckii in 48 h. The research results were as follows:1%~6% NaCl in the medium could restrain an augment in the number of Lactobacillus delbrueckii significantly(p<0.05). At the same time,it could reduce the decline of pH. Furthermore,1%~3% NaCl could influence the putrescine produced by Lactobacillus delbrueckii at the level of genes. They had few effect on the regulating gene-aguR’s transcription(p>0.05)but could inhibit the transcription of aguBDAC operon highly significantly(p<0.01). The production of putrescine was sinificantly(p<0.05)decreased by 1%~3% NaCl. The larger concentration of NaCl caused greater inhibiting effects.Lactobacillus delbrueckii in this study was a kind of infectious microbe isolated from smoked horsemeat sausages. It could be dealed with proper concentration of NaCl in the smoked horsemeat sausages making process so that infectious microbe such as Lactobacillus delbrueckii which came into being in the fermentation process would be restrained. Therefore,putrescine accumulation in the product could be diminished.