Table 3. Influence of carbon type and C/N ratio on Gaussian parameters for specific methane yield during anaerobic digestion start-up phase

Carbon type	C/N ratio	Maximum specific methane yield (N mL/g VS/ day)	t0(days)	a (N mL/g VS day)	b (days)
Starch	10	53.5	9.9	44.7	3.9
	25	60.5	9.9	54.4	2.9
	40	59.1	10.0	56.5	2.8
Cellulose	10	50.5	12.7	46.1	4.5
	25	47.3	14.9	44.1	6.1
	40	52.7	16.3	49.1	6.2
Xylan	10	42.2	9.4	43.1	3.9
	25	48.7	10.3	46.8	3.8
	40	42.0	10.4	41.1	4.3
SEM		2.14	0.82	2.87	0.57
p-value1)	C	0.001	0.001	0.008	0.000
	CN	0.158	0.096	0.160	0.777
	C × CN	0.054	0.330	0.096	0.154

C, effect of carbon type; CN, effect of carbon: nitrogen ratio; C × CN, interaction between carbon type and carbon: nitrogen ratio.
C/N ratio, carbon to nitrogen ratio; SEM, standard error of means.