Analysis Of Microorganism Community Structure In The Fermentation Process Of Sichuan Traditional Pickles And Industrial Pickles

Sichuan pickles which has a long history is a raditional vegetables fermented foodsfavored by consumers. The fermentation process of Sichuan pickles is the result of theinteraction of the various entities in a microbial community. To understand the nature offermentation thoroughly, we must firstly understand the composition of the microbial flora inSichuan pickles.In the subject, we used a method of constructing16S rRNA gene clone library to studythe microorganism community structure in the Sichuan traditional pickles and Sichuanindustrial pickles. And the microbial diversity and dynamic were assessed by diversity index,rarefaction analysis and similarity coefficient.The results of experiment show that, a total of129representative clones were recoveredin the Sichuan traditional pickles sample PC through the16S rRNA gene analysis, and wereidentified as lactic acid bacteria belonging to different species of two genera Lactobacillusand Pediococcus with proportion of16.3%and10.1%respectively. The L. pentosus(50.4%),L. plantarum(16.3%) and P. damnosus(10.1%) were the dominant species in Sichuantraditional Pickle, though L. paralimentarius, L. sunkii, L. brevis, L. kisonensis, L.acetotolerans and L. namurensiswere also found.The main microorganisms in thel Sichuan industria pickles sample PB1、PB2、PB3were Vibrio、 Cobetia and Halomonas. And the proportion of Vibrio、 Cobetia andHalomonas in the sample PB1、PB2、PB3was32.1%、29.6%、0,30.4%、15.9%、15.9%and13.5%、32.4%、12.1%respectively. With the increasing of fermentation time, Vibrioand Cobetia showed a decreasing trend while the Halomonas had an increasing trend affectedby the high salt environment.The Lactic acid bacteria was not main microorganisms in theSichuan industrial pickles, but its content was showing an increasing trend and reached itsmaximum in the PB3. In the fermentation of Sichuan industrial pickles, the main Lactic acidbacteria were Le. Gelidumand P. damnosus in the beginning, L. plantarum，L. brevis and P.damnosus in the medium-term and L. sakei, L. plantarum, L. brevis and L. sunkii in the latestage.By the diversity analysis, the coverage of sample PC was88.1%and the coverage ofsample PB1、PB2and PB3was100%. The result showed that the microbial communitystructure detected was able to characterize the type and quantity of bacteria in Sichuan picklessample. These results revealed the microbial diversity and the microbial community structurein Sichuan Pickle, showed a lot of undiscovered bioinformation, provided a strong theoretical foundation for people to study the fermentation mechanism and the formation mechanism offlavor factor in the Sichuan pickles and also provided an important reference for thepreparation of new lactic acid fermentation agents.