Environmental Biotechnology Questions and Answers – Microbial Production of Fuels

This set of Environmental Biotechnology Multiple Choice Questions & Answers (MCQs) focuses on “ Microbial Production of Fuels”.

1. Why is S. cerevisiae is used to derive butanol?
a) It has high growth rate
b) It can overcome toxicity
c) Changes its own cell wall composition in response to toxicity
d) High tolerance to butanol
View Answer

Answer: d
Explanation: S. cerevisiae has high toluene level and produces butanol through fermentation of carbohydrates while the other options like high growth rate, overcoming toxicity and changing of the cell wall composition is related to E. Coli, Pseudomonas putida and bacillus subtilis respectively and not related to s. cerevisiae.

2. Which fatty acids can’t be used as abiofuel directly?
a) Ionic nature of carbonyl groups
b) Hydrophobic nature
c) If degree of saturation is high
d) Variation of length
View Answer

Answer: a
Explanation: The ionic side of the fatty acid is water-soluble. They must be converted to non-soluble and non-ionic to be used as a biofuel.

3. Which of these is not one of the main biomass feedstocks?
a) Sugar
b) Starch
c) Lignocellulose
d) Hemicellulose
View Answer

Answer: d
Explanation: Hemicellulose is not one of the main biomass feedstocks as it is demanded from the pretreatment of lignocellulose. Lignocellulose includes grains, potatoes, cassava and the pretreatment as these are cellulose and hemicellulose.

4. Which of these is not a direct treatment on hemicellulose?
a) Cellulase production
b) Hexose fermentation
c) Syngas fermentation
d) Pentose fermentation
View Answer

Answer: c
Explanation: Syngas fermentation is treatment on hemicellulose. It is also a treatment after the lignocellulose is gasified. Hence syngas fermentation is not a direct treatment.

5. Which of these are acetotropic methanogens?
a) Methanoculleus thermophilicus, Methanosphaera stadtmanii
b) Methanosarcina thermophila, Methanosaeta concilii
c) Methanosarcina thermophila, Methanosphaera stadtmanii
d) Methanoculleus thermophilicus, Methanosarcina thermophila
View Answer

Answer: b
Explanation: Methanosarcina thermophila and Methanosaeta concilii, both are acetotropicand it also comes under the archaea group. While Methanosphaerastadtmanii and Methanoculleus thermophilicus are hydrogenotrophics.
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6. Which of these bacteria is a redox mediator in microbial fuel cells?
a) Pseudomonas aeruginosa
b) Geothrix ferementans
c) Desulfuromonas acetoxidans
d) Shewanella oneidenensis
View Answer

Answer: b
Explanation: Pseudomonas aeruginosa and Shewanella oneidenensis are used as nanowires for electron transfer. Desulfuromonas acetoxidans used as exoelectrogens while Geothrix ferementans produce their own chemical redox mediators.

7. Which has the correct descending order of Inhibitory Capacity?
a) Propionic > Butyric > Acetic > Lactic
b) Propionic > Acetic > Butyric > Lactic
c) Lactic > Butyric > Acetic > Propionic
d) Lactic > Acetic > Butyric > Propionic
View Answer

Answer: a
Explanation: pKa values of Propionic, Butyric, Acetic and Lactic are 4.88, 4.82, 4.76 and 3.85 respectively.

8. Which of the following is an undesirable microbe in endogenic silage microorganism with simple sugar as the substrate?
a) Homolactic
b) Propionic acid bacteria
c) Heterolactic
d) Yeast
View Answer

Answer: d
Explanation: Yeast is not much in the demand with respect to endogenic silage microorganisms. Yeast causes air infiltration which is not desirable.

9. Which of following is not a focus in conversing microbial communities to biofuel?
a) Substrate Flexibility
b) High productivity
c) Higher number of products in one process
d) Tolerance to stress
View Answer

Answer: c
Explanation: Product specificity is focused on the mentioned process. Therefore, higher number of products in one process is not a focus in here.

Sanfoundry Global Education & Learning Series – Environmental Biotechnology.

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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