Plackett–Burman Combined with Box–Behnken to Optimize the Medium of Fermented Tremella Polysaccharide and Compare the Characteristics before and after Optimization

Table 3

Factors and levels for the Box–Behnken design.

Factor	Name	Units	Low level (−1)	Middle level (0)	High level (1)
A	Potato extract	%	21.00	22.00	23.00
B	Glucose	g/L	28.48	29.32	30.16
C	Peptone	g/L	2.56	2.62	2.68