Table 2. Statistical Analysis of the Model from the PBD^a.

source	SS	Df	MS	F-value	P-value
model	4.51	9	0.5014	414.99	0.0024*
A, glass bead addition	0.0154	1	0.0154	12.75	0.0703
B, antifoam reagent addition	0.1900	1	0.1900	157.25	0.0063*
C, surfactant addition	0.0052	1	0.0052	4.31	0.1735
D, working volume	0.0052	1	0.0052	4.31	0.1735
E, agitation	0.0007	1	0.0007	0.56	0.5327
F, culture temperature	0.9352	1	0.9352	773.97	0.0013*
G, fermentation period	3.3600	1	3.3600	2780.86	0.0004*
H, fermentation pH	0.0010	1	0.0010	0.83	0.4574
J, inoculum size	0.0001	1	0.0001	0.06	0.8265
residual	0.0024	2	0.0012
cor total	4.52	11

^aModel summary: R², 0.9995; adjusted R², 0.9971; predicted R², 0.9807. *indicates P < 0.05, 5% significant level. SS, sum of squares; Df, degree of freedom; MS, mean sum of squares.