The Biofilm Formation Of Bifidobacterium And Its Application

Bifidobacterium is the autochonous flora in the human body and animal intestine,with the maintenance of intestinal microecological balance,regulating the physiological function of the host and other functions.In the food,health care products and pharmaceutical industry,it has great application value.Bifidobacterium powder as one of the most common Bifidobacterium preparations,is widely used in solid beverages,starter and other products.It was found that the damage of oxygen and temperature during the process of powder production is the main factor that causes the death of Bifidobacteria.Therefore,how to improve the survival rate of Bifidobacteria become a hotspot.Biofilm is an adaptive mechanism for bacteria to deal with environmental stress,which can reduce the lethal effect of adverse environment on bacteria.The aim of this study was to explore the feasibility of Bifidobacterium biofilm in the preparation of powder and analyze the biofilm formation and biological characteristics of Bifidobacterium biofilm,and provide the basis for the practical application of Bifidobacterium biofilm in the preparation of bacterial powder.The main results of this topic were as follows:1.The biofilm formation analysis of Bifidobacteria.The microplate method was used to study the biofilm forming ability of 7 kinds of 49 strains Bifidobacteria,such as Bifidobacterium longum,Bifidobacterium breve,Bifidobacterium bifidum,Bifidobacterium adolescentis,Bifidobacterium animalis and Bifidobacterium pseudocatenulatum.The results showed that the biofilm formation ability of Bifidobacterium was strain specificity,and there was no species specificity.The CLSM results showed that Bifidobacterium biofilm had a certain organizational structure,dead bacteria density with the depth of the biofilm layer increased.In addition,it was found that the culture conditions significantly affected the biofilm formation ability of Bifidobacterium.The concentration of glucose,sodium chloride and magnesium sulfate had an optimum concentration for the biofilm formation ability of Bifidobacterium,and the concentration was strain specificity.Bile salt showed inhibition of Bifidobacterium biofilm formation,the greater the concentration of bile salts,the stronger the inhibition.The effect of the addition of mucin,oxygen stress,heat stress and cold stress on the biofilm forming ability of Bifidobacterium showed two sides.They could promote a part of Bifidobacteria to form biofilm,but also showed inhibition,different strains of Bifidobacteria were affected by different degrees.2.The biological characteristics of Bifidobacterium biofilm were elucidated.The results showed that the biofilm status of Bifidobacterium was more heat-resistant and oxygen-resistant than the floating state.There were some differences among the different strains,and the highest could be more than 21 times.In addition,biofilm could signally improve the survival rate of vacuum-drying and freeze-drying.3.Study on the fermentation production of Bifidobacterium biofilm.Using soybean powder as a solid interface to produce Bifidobacterium bifidum CCFM641 fermentor biofilm,bacterial sludge to 1:10(w/v)ratio of mixed protective agent dry survival rate of the highest.The survival rate of vacuum drying reached 15.90%,and the survival rate of freeze drying reached 39.62%,which was 7.16 times and 1.58 times of the dry survival rate of planktonic bacteria.In conclusion,this paper studied the biofilm formation,biological characteristics and fermentor production of Bifidobacterium,which laid a theoretical and practical basis for the industrial production of Bifidobacterium biofilm and powder.