Genomic Analysis Of Bifidobacterium Catenulatum IMAUFB087 And The Storage Characteristics Of Its Fermented Milk

Bifidobacterium catenulatum(B.catenulatum)is commonly found in the human gut,and some of its strains have been shown to have potential probiotic effects.In this study,the whole genome of IMAUFB087,a strain of B.catenulatum with great function of weight loss,was sequenced,and comparative genomic analysis was conducted in combination with the whole genome sequence of 11 published strains of B.catenulatum,to explore the functions of IMAUFB087 at the genome level.It was then applied to fermented milk to explore its effect on storage characteristics of fermented milk.The main results are as follows:(1)The complete genome of IMAUFB087 was sequenced and analyzed.This study found that the genome size of IMAUFB087 was 2.05 Mb and GC content was 56.12%.IMAUFB087 has 132 specific genes within species,including probiotic genes related to the production of extracellular polysaccharides(e.g.eps,pgl K)and capsular polysaccharides(e.g.MA20).(2)Through the annotation of the core gene function of 12 B.catenulatum strains,this study found that B.catenulatum is rich in the metabolic functions.The pan-genomic metabolic network of B.catenulatum was constructed based on KEGG annotation,among which IMAUFB087 had eight specific metabolic enzymes in species,including a key enzyme in the metabolic pathway of folate.Based on the CAZy annotation,complete metabolic gene clusters of fructose-oligosaccharides,xylan,galactose oligosaccharides and isomaltose oligosaccharides were identified in IMAUFB087.(3)IMAUFB087 was inoculated into fermented milk as a single bacteria starter,and it had a low viable bacteria count during storage period,while Lacticaseibacillus casei Zhang could significantly improve its viability count(P< 0.05).(4)The effect of IMAUFB087 on storage characteristics of fermented milk for 21 days was detected by co-fermentation of IMAUFB087 with basic starter.It was found that IMAUFB087 could significantly improve the water holding capacity,hardness,cohesion and viscosity of fermented milk(P<0.05).The combination of IMAUFB087 and Lacticaseibacillus casei Zhang further improved the water holding capacity and viscosity of fermented milk(P<0.05).This study revealed the general genomic characteristics of the probiotic bacteria B.catenulatum IMAUFB087,and confirmed its potential beneficial and functional properties at the genomic level,which provides genomic evidence for the probiotic effects of IMAUFB087.In addition,the application of IMAUFB087 in fermented milk is not only a preliminary study of the fermentation characteristics of IMAUFB087,but also provides a reference for the application of B.catenulatum in fermented food.