The Bacteria Shewanella Putrefaciens Involved In The Metabolism Of TMAO

The strains of bacteria were obtained by isolating and purifying the mixed florasfrom epidermis and viscera. The possible metabolic pathway for these mixed floraswas analyzed in the TMAO metabolism process by detecting the TMAO metabolicability. For the isolated strains, five strains which strain which could metabolizeTMAO stably in repeated culture was named as YY.The bacteria was identified asShewanella putrefaciens，confirmed by Biolog method and, which were reported asthe TMAO metabolism bacteria before. The fact mentioned above was correspondingwith the present reports. TMAO was may be the terminal electron receptor of electrontransportation during the energy metabolism of the YY strains. At the end of thetransportation, TMAO was reduced to TMA that is not able to be decomposed tosmaller metabolite such as formaldehyde and other substance containing compositionof nitrogen.TMAO utilization and bacterial growth of YY under aerobic and anaerobicculture condition in24h were analyzed and the period of TMAO reducing wasidentified as growth logarithmic period of YY, which is consistent with the presentreports. YY were cultured aerobically and anaerobic, respectively. With the detectionof TMAO release and its metabolic products in the fermentation fluid, the resultsshowed that the reducing process of TMAO was not inhibited and even enhanced byoxygen during the growth of YY. This indicates that the reducing enzymes in thosetwo strains may be slightly different from them in other strains reported before. It alsodemonstrates that the enzymes boast much higher activity and the electrontransportation pathway is differ from the way in cytochrome represented by E.coliIn addition, the suitable amount of YY suspension was added into the meat offresh Cod and cultured at4℃and room temperature constantly, respectively, whilethe fresh Cod meat added sterile physiological saline as control. Through sensory observation and platecount method, we found that the meat with YY suspension rottedrapidly which resulted from large of bacteria fertilization under roomtemperature.Comparing the results of TMAO and its metabolic products detection inthe Cod meat with the control, we found that TMAO was reduced to TMA rapidlywhen the fish meat was infected by bacteria and the TMAOase was activated quicklyin fish meat. TMA can be detected in4h and the amount increased during the meatwas spoiled. It suggested that the Cod meat could provide a good growth conditionsfor YY. After being added into Cod meat, YY grew rapidly and resulted the meattissues into softening and hydrolyzation, which accelerated the spoilage of fish meat.The process improved the release and activation of TMAOase from Cod tissues andthe amount of DMA and FA increased rapidly in the fish tissues as a result.With the temperature increasing from15to35℃, the rate of TMAOmetablization increased slightly and reached the same after8hours. The optimumsalinity of YY which is a strain widely resistant to salt is15g/L~35g/L. The abilitiesof growing and metabolizing TMAO of YY was limited with the salinity rising. Thesalinity showed more notble influence on TMAO metabolism than the growth ofstrain.The metabolic rate of microbial TMAO was affected by pH, as the pH has agreat effect on the metabolism in vivo enzyme activity of microbial. As the reactionproceeded, the pH of fermentation broth became neutral, which was adjustedautomaticly by YY during the growth and metabolism. Under the conditions of pH6.0and9.0as well as outside the pH range in the medium, strain YY did not have thereduction of TMAO. There was no correlation between the growth situation ofstrain YY and the content of TMAO. Metabolism aspects in TMAO related products,the results of ion chromatography analysis displayed: at the same time, the product ofTMA content was, it indicated that the concentration of TMAO had not affect themetabolism rate ofstrain YY to TMAO.