Preparation Of Biofilm-phenotype Saccharomyces Boulardii And Its Probiotic Effects

Saccharomyces boulardii(S.boulardii)is a subspecies of Saccharomyces cerevisiae.Compared with other bacterial probiotics,S.boulardii possesses natural advantages in drug resistance,heat resistance,and acid resistance.In addition,S.boulardii can prevent and treat intestinal related diseases.However,S.boulardii is also susceptible to damage from environmental stress factors,resulting in decreased stability and vitality,similar to other probiotics.Biofilm is an important survival strategy for microorganisms,possessing enhanced tolerance to environmental stress.Unfortunately,there are relatively a few studies on probiotics biofilms,especially Saccharomyces boulardii biofilms.It has been found that pore structure and specific surface area of the carrier materials have great impacts on biofilm formation.In this study,a series of porous materials were prepared for biofilm formation.The most suitable material was selected from several porous materials based on the results of qualitative and quantitative analysis of S.boulardii biofilms formed on these materials.The tolerances of biofilmphenotype S.boulardii were compared with planktonic S.boulardii under different environmental stresses,including in vitro simulated gastric juice,intestinal juice,bile salt solution,heat treatment,and storage time.Besides,the antibacterial properties of S.boulardii were also analyzed in vitro.Finally,the probiotic effects of biofilmphenotype S.boulardii on enteritis mice were studied.The research results were as follows:(1)The bacterial cellulose/corn starch composite gel with ratio 1/2 was the best material for the formation of S.boulardii biofilm.After ultrasonic and enzymatic treatment,there was still a large amount of S.boulardii adhered on the material and the biofilm structure was obvious.(2)Biofilm-phenotype S.boulardii showed better tolerance in the simulated gastric juice,intestinal juice,and bile salt solution than planktonic S.boulardii.After 3h of digestion in the simulated gastric juice,the change of viable bacteria of the planktonic S.boulardii and the two biofilm-phenotype S.boulardii were-0.09 Log CFU/m L,-0.09 Log CFU/m L and-0.09 Log CFU/m L,respectively.After 3 h of digestion in the simulated intestinal juice,the change of viable bacteria of planktonic S.boulardii and two biofilm-phenotype S.boulardii were-0.09 Log CFU/m L,0.04 Log CFU/m L and 0.17 Log CFU/m L,respectively.After 3 h of digestion in 0.3 g/L bile salt solution,the change of viable bacteria of the planktonic S.boulardii and the two biofilm-phenotype S.boulardii were-0.91 Log CFU/m L,-0.16 Log CFU/m L and-0.11 Log CFU/m L,respectively.(3)In the in vitro antibacterial experiments,the change of viable bacteria of Escherichia coli co-cultured with planktonic S.boulardii or two biofilm-phenotype S.boulardii were-0.42 Log 10 CFU/m L,-0.65 Log 10 CFU/m L and-0.72 Log 10CFU/m L,respectively.Results demonstrated that biofilm-phenotype S.boulardii had stronger antibacterial abilities than planktonic S.boulardii.(4)S.boulardii facilitated intestinal recovery and serum IL-6 levels reduction of the model mice with colitis.Low-dose biofilm-phenotype S.boulardii or high-dose planktonic S.boulardii could achieve good therapeutic effect.In addition,S.boulardii showed an obvious recovery effect on the diversity of mouse intestinal flora.