Study Of Plantaricin ZJ317 Producted By L.Plantarum ZJ317

Lactic acid bacteria(LAB),a kind of Probiotics which play an essential role in food fermentation industry.In 1928,the lactic acid bacteria metabolites were reported had antimicrobial effects for the first time,which was proved to be barteriocin.In 1969,FAO/WHO confirmed that the lactein Nisin was the safe,efficient and reliable food preservatives.Due to the increasing harm of food pathogens and synthetic preservatives in recent years,people began to search natural preservatives in place of traditional preservatives.Owing to its safety and high efficiency,lactein gets more and more attention.At the same time,because of lactein is non-toxic,non-residual,non-drug-resistant,it is also considered to be the most effective antibiotic alternative.We screened a LAB which has antibacterial activity from baby feces and initial research was carried out.We found that:(1) Through the observation of morphological,physiological and biochemical analysis,the identify of 16S rRNA,we found that the LAB was a Lactobacillus plantarum,and named Lactobacillus plantarum ZJ317 for the time being,the barteriocin named plantaricin ZJ317.Plantaricin ZJ317 showed the most active and the highest stability in the acidic conditions.When the pH was higher than 4.5,it will lose activity.Heat-resistant,dealt with 30min at 121℃,it can retain 70%of the activity.And it was sensitive to protease K and trypsin,but not to catalase. The molecular size of plantaricin ZJ317 is about 4kDa.(2) Plantaricin ZJ317 belonged to the broad spectrum barteriocin,including most of the gram-negative bacteria and some gram-positive bacteria,such as P.putida,B. subtilis,L.monocytogenes,S.flexneri,S.citreus,E.coli,Salmonella,etc.But it didn't restrain its own growth.(3) L.plantarum ZJ317 contain several genes related to the production of barteriocin.One of them have a ORF about 129 bp length,which was consider as suspected gene involved in the production of plantaricin ZJ317.(4)Changed of the media component and culture conditions could increase the activity of plantaricin ZJ317.Yeast extract,sucrose is more suiTable.for L.plantarum ZJ317 product plantaricin ZJ317.When the medium composition were yeast extract 10g/L,peptone 10g/L, ammonium citrate 2g/L,sucrose 10g/L,glucose 10g/L of,dipotassium hydrogen phosphate 4g/L,Tween 80 1mL/L,and cultivate at initial pH 6.5,30℃,the activity can accelerate up to 2.5-fold than the original.