Question

The last step in biogas production is carried out by
A)Decomposer microbes
B)Fermentative microbes
C)Methanogens
D)Thermoacidophiles

Answer 1

It includes in the formation of methane anal identified only from the domain archaea which is a group of phylogenetically distinct from both eukaryotes and bacteria. Some also live in a very close association with anaerobic bacteria.

Complete step by step answer:
-By the breakdown of organic matter in the absence of oxygen, biogas is produced which is the mixture of gases consisting of methane and carbon dioxide. It can be generated from raw materials like agricultural waste, manure, municipal waste, plant material, sewage, etc.
The biogas production involves three steps

1. Hydrolysis - By extracellular enzymes of microorganisms such as amylase, protease, and Lipase, the organic matter is enzymolysed externally. The complex carbohydrates, proteins, and lipids are decomposed by the bacteria into shorter parts.
   Example - Polysaccharides converted into monosaccharides and protein converted into peptides and amino acids.
   2)Fermentation - In this step acid-producing bacteria are involved, convert complex organic compounds like protein, fats, and carbohydrates into simple compounds.
   -Also the primary fermentation products also appear such as volatile organic acids, alcohols, amino acids, carbon dioxide, and hydrogen sulfide.
   -They all act as methane-producing bacteria convert organic acid into biogas.
   3)Methane formation - In this step, methane-producing bacteria are involved in decomposing the low molecular weight compound. Carbon dioxide, hydrogen, and acetic acid are utilized to form methane and carbon dioxide in an anaerobic environment. This process is known as methanogenesis.

So, the correct answer is, "Methanogens".

Additional information:
Decomposer microbes - the remains of dead organisms are broken down by an organism known as a decomposer. It includes bacteria and fungi. They carry out the process of decomposition.
Fermentative microbes - In the production of methane these bacteria play an essential role. The enzymatic decomposition and utilization of foodstuffs particularly carbohydrates by microorganisms are known as fermentation.
Thermoacidophiles- a microorganism include both thermophilic microbes and acidophilic microbes because they can grow in both high temperatures and low pH.

Note:
-From the agricultural waste the biogas and the biofertilizers are produced which is based on the quality of organic substances that are used to produce biogas when decomposed in anaerobic conditions.
-The three steps are involved in the decomposition of organic substances and usually involved two groups of microorganisms that are acidic and methane bacteria.