紫色红曲霉菌丝体多糖体外肠道酵解特性的研究

In Vitro Fermentation Characteristics of Endopolysaccharides Extracted from Monascus purpureus

为研究红曲霉不同菌丝体胞内多糖(endopolysaccharides,MPS)组分MPS-1、MPS-2、MPS-3和MPS-4的肠道酵解特性,采用体外猪结肠模型,测定不同酵解时间多糖分子量、猪结肠短链脂肪酸(Short-chain fatty acids,SCFAs)和肠道菌群的变化。结果表明,经肠道酵解后,各多糖处理组中乙酸、丙酸和丁酸产量较高。在酵解48 h时,MPS-2和MPS-3处理组酵解产生的总SCFAs含量显著(P<0.05)增加,分别从22.80、17.20 mmol/L增至63.08、71.61 mmol/L,各多糖处理组总SCFAs含量从高到低顺序为MPS-3>MPS-2>MPS-1>MPS-4。16S rDNA结果显示,MPS处理后,在门水平上,厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)是主要的优势菌门,且降低了Firmicutes/Bacteroidetes的比例。在属水平上,随着酵解时间的延长,拟杆菌属(Bacteroides)、普雷沃菌属(Prevotella)和副拟杆菌属(Parabacteroides)等有益菌的丰度升高,有害菌属包括链球菌(Streptococcus)、梭菌属(Clostridium)等的丰度显著(P<0.05)下降,其中MPS-2和MPS-3处理组酵解过程中有益菌的相对丰度较大,有害菌的相对丰度较低。综上,红曲霉菌丝体多糖作为益生元在功能性食品及生物医药领域具有很大的应用潜力。

To investigate the intestinal fermentation characteristics of different endopolysaccharides(MPS)sub-fractions MPS-1,MPS-2,MPS-3,and MPS-4 from Monascus purpureus mycelium,an in vitro pig colon model was used to determine the changes in molecular weight of the polysaccharides,the contents of short-chain fatty acids(SCFAs),and gut microbiota at different fermentation times.The results showed that after intestinal fermentation,the acetic acid,propionic acid,and butyric acid production in each MPS treatment group was higher.At 48 h of fermentation,the total SCFAs content produced by the MPS-2 and MPS-3 treatment groups increased significantly(P<0.05),from 22.80 and 17.20 mmol/L to 63.08 and 71.61 mmol/L,respectively.The total SCFAs concentration of each polysaccharide treatment group was MPS-3>MPS-2>MPS-1>MPS-4 in descending order.The 16S rDNA results revealed that after MPS treatment,Firmicutes and Bacteroidetes were the main dominant bacteria at the phylum level,and the ratio of Firmicutes/Bacteroidetes was reduced.At the genus level,with the extension of fermentation time,the abundance of beneficial bacteria such as Bacteroides,Prevotella,and Parabacteroides increased,while the abundance of harmful genera,including Streptococcus and Clostridium,decreased significantly(P<0.05).Among them,the MPS-2 and MPS-3 treatment group had the higher abundance of beneficial bacteria and the lower abundance of harmful bacteria.In summary,MPS have great potential as prebiotics in the fields of functional foods and biomedical applications.