Tag: microbes in waste treatment and biogas

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Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Which of the following is correct about biogas?

  1. Methane gas is produced along with ethyl alcohol by methanogen

  2. Methanogens acts on cellulose and release biogas

  3. Biogas is produced by thunder and lightening

  4. Maximum gas found in biogas is $CO _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
  • Methanogens are present in the rumen of cattle that is present in dung as well. Methanogens acts on the cellulose content of the and  It helps in the production of methane gas that is a component of biogas.
  • Hence Methanogens acts on cellulose and release biogas is a correct statement.
  • So, the correct answer is 'Methanogens acts on cellulose and release biogas'.
Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Biogas production is rate limited by

  1. Production of methane

  2. Cellulose digestion

  3. Conversion of monomers to organic acids

  4. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The breakdown of complex polymers like cellulose into simpler monomers is the rate-limiting step in anaerobic digestion. This hydrolysis step is often the slowest part of the process.

Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Temperature suitable for biogas production is

  1. $35^o-40^o$C

  2. $20^o-25^o$C

  3. $30^o-35^o$C

  4. $40^o-44^o$C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Biogas production occurs by the action of anaerobic bacteria on waste materials or raw materials. The reactions are made to occur in specially designed large sized tanks called digesters. The bacteria that decompose  the raw materials and produce biogas can be thermophilic if they survive at a higher temperature or mesophilic if they survive at a moderate temperature. Mesophilic bacteria are active at an optimum temperature of 35° - 40°C and thermophilic bacteria are active at an optimum temperature of 50° - 55°C . 
Hence, option A matches the correct temperature suitable for biogas production.
So, the correct answer is '35° - 40°C'.
Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Match and find the correct combination.

(a) Fermenting malted cereals and fruit juice (i) Clots in Blood vessels
(b) Production of large holes in Swiss cheese (ii) Digestion of sludge by bacteria and fungi resulting in emission methane and other gases
(c) Myocardial infarction (iii) Production of ethanol
(d) Biogas (iv) Blood cholesterol lowering agent
(v) Production of large amount of CO$ _2$

  1. a-iii, b-v, c-iv, d-ii

  2. a-i, b-ii, c-iii, d-iv

  3. a-iii, b-v, c-i, d-ii

  4. a-v, b-iv, c-iii, d-ii
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(a) Fermenting malted cereals produces ethanol (iii). (b) Swiss cheese production involves CO2 release (v). (c) Myocardial infarction is associated with blood clots (i). (d) Biogas involves sludge digestion (ii).

Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Identify the correct pair of characters of a bacterium which is used in the production of methane.
(i)   Recyclers of inorganic nutrients
(ii)  Present in stomach of cattle
(iii) Obtain energy from sunlight
(iv) Aerobes

  1. ii, iii

  2. i, ii

  3. i, iv

  4. iii, iv
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Methanogens are anaerobic bacteria (not aerobes) that recycle inorganic nutrients and are found in the rumen of cattle to aid in cellulose digestion.

Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

The order of bacteria active in conversion of organic wastes into biogas is

  1. Hydrolytic $\rightarrow$ Acetogenic $\rightarrow$ Methanogenic

  2. Methanogenic $\rightarrow$ Acetogenic $\rightarrow$ Hydrolytic

  3. Methanogenic $\rightarrow$ Hydrolytic $\rightarrow$ Acetogenic

  4. Acetogenic $\rightarrow$ Methanogenic $\rightarrow$ Hydrolytic
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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 $\rightarrow$ Acetogenic $\rightarrow$ Methanogenic'.

Multiple choice zoology bioenergy biogas environmental use of microorganism microbes in waste treatment and biogas

Biogases produced during sewage treatment are 

  1. ${H} _{2}S, \,{N} _{2}, \,{CH} _{4}$

  2. ${CH} _{4}, \,{H} _2{S}, \,{CO} _{2}$

  3. ${CH} _{4}, \,{O} _{2}, \,H _2S$

  4. $H _2S, \,CH _4, \,SO _2$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The Biogases produced during sewage treatment are

1.Methane (CH$ _4$)
2.Hydrogen sulfide (H$ _2$S)
3.Carbon-dioxide (CO$ _2$).
So, the correct option is 'CH$ _4$, H$ _2$S, CO$ _2$'.