The order of bacteria active in conversion of organic wastes into biogas is
The order of bacteria active in the conversion of organic wastes into biogas is hydrolytic, acetogenic, methanogenic.
Hydrolytic- Insoluble organic polymers, such as carbohydrates, are broken down to soluble derivatives which are used by bacteria.
Acetogenic- Acidogenic bacteria then convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids. These bacteria convert these resulting organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide.
Methanogenic- The methanogens convert the product of acetogenic step to methane and carbon dioxide. The produced gas consisting of methane, carbon dioxide, and traces of other ‘contaminant’ gases is known as biogas.
So, the correct answer is 'Hydrolytic → Acetogenic → Methanogenic'.