Table 1.

The factors and levels of the orthogonal design.

Factor	Number	Unit *	Level
			1	2	3	4
Fructose	F1	g	1	3	5	7
Glycerin	F2	g	1	3	5	7
Peptone	F3	g	1	3	5	7
MgCl2	F4	g	0.05	0.08	0.11	0.14
VB1	F5	g	0.05	0.08	0.11	0.14
VB2	F6	g	0.05	0.08	0.11	0.14
Water–materials ratio a	F7	%	80	90	100	110
CaCl2	F8	g	0.5	1	1.5	2
Corn bran	F9	g	3	4	5	6

* The rice amount of each run was set at 50 g. ^a Water–materials ratio was calculated according to total dry substrate weight.