Meanwhile, the biogas production of the
ratio 5:2 maintained at the level of 500 mL. And the biogas production
curve of the ratio 1:1 and 2:3 fell in a straight line until the
biogas production declined to about 500 mL. However, the biogas
production of the ratio 2:1 and 3:2 maintained at a level of about
1500 mL for 8 days and then the biogas production of them
reduced to about 400 mL at the end of the experiment.