There are several earlier report where different concentration of yeast extract is added to the culture media for optimized EPS production, and the resultant EPS also concisted of mannan. However, there is no report that the mannan came from yeast extract (DOI: 10.1016/j.ijbiomac.2019.09.139, DOI: 10.1023/B:WIBI.0000033068.45655.2a). The same applies for our study too. In addition, the yeast mannan have β-(1→4) linkage and the one found in this work have α-linkage type. This allows us to conclude they are different polysaccharides.
Figure 6: Bacterial EPSs are normally composed of repeating units.