Investigation of Antimicrobial Activity and Statistical Optimization of Bacillus subtilis SPB1 Biosurfactant Production in Solid-State Fermentation

Table 4

Estimated effect, regression coefficient, and corresponding 𝑡 and 𝑃 values for surfactin production in eight variable Plackett-Burman design experiments.

Code	Estimate coefficient	F. inflation	Standard deviation	𝑡 value	𝑃 value
Intercept	13.937		0.238	58.36	<0.01***
A	1.463	1.00	0.238	6.12	*
B	1.162	1.00	0.238	4.87	*
C	0.013	1.00	0.238	0.05	93.3
D	1.512	1.00	0.238	6.33	*
E	0.912	1.00	0.238	3.82	6.2

*** 𝑃<0.01 (very significant).
*(Significant).