Question

Bacillus subtilis are
(a) Hay bacteria
(b) Nitrifying bacteria
(c) Ammonifying bacteria
(d) Intestinal bacteria

Answer 1

Hint: This bacteria is also known as grass bacillus and is a Gram- positive that catalase- positive bacteria. They are found in the upper layer of the soil and the gastrointestinal tract of ruminants and living individuals.  

Complete answer:
Bacillus subtilis is a member of the genus subtilis and is also called as ‘hay bacillus’ and can degrade plant’s polysaccharides and pectin. They are hay bacteria and are small and rod-shaped. Bacillus subtilis can divide to make two daughter cells by binary fission or asymmetrically by producing a single endospore. It can form a tough and protective endospore layer under nutritional stress through the use of hydrolysis which allows it to tolerate extreme environmental conditions such as drought, salinity, and extreme pH. It is evident that it is a facultative anaerobe but was historically classified as an obligate aerobe. It is the best-studied Gram-positive bacterium and also the best to study bacterial chromosome replication and cell differentiation. It is also used in industries by biotechnology companies and secrets enzymes. Before the process of sporulation(this is happening under stressful conditions like nutrient deprivation) the cells might become motile producing flagella and can take up DNA from the environment.
So, the correct answer is 'Hay bacteria.'

Note:
- The nitrifying bacteria are chemolithotrophic bacteria that convert ammonia into nitrates and it includes Nitrosomonas and Nitrobacter.
- Ammonifying bacteria like the Bacillus Vulgaris and the Bacillus ramosus are bacteria that convert ammonia into atmospheric nitrogen. They can be symbiotic (form root nodules and supply the ammonia to the plant) or non- symbiotic (ammonify openly & use ammonia for their metabolism).
- A colon bacteria like E. coli is a facultative parasite of the large intestine of mammals.