45. Match the microorganisms in Group I with their fermentation products in Group II.

Group I	Group II
P) Leuconostoc mesenteroides	1) Cobalamin
Q) Rhizopus oryzae	2) Sorbose
R) Gluconobacter suboxydans	3) Dextran
S) Streptomyces olivaceus	4) Lactic acid
	5) Butanol

(A) P-5, Q-4, R-2, S-1
(B) P-5, Q-3, R-2, S-4
(C) P-3, Q-4, R-1, S-2
(D) P-3, Q-4, R-2, S-1

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Step-by-Step Matching With Explanation

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P) Leuconostoc mesenteroides → Dextran (3)

• Leuconostoc mesenteroides is a heterofermentative lactic acid bacterium.

• It is industrially used for dextran production from sucrose.

• Dextran is a polysaccharide widely used in food and pharmaceutical industries.

✅ Correct match: P–3

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Q) Rhizopus oryzae → Lactic acid (4)

• Rhizopus oryzae is a filamentous fungus.

• It is commonly used for lactic acid fermentation, especially in organic acid production.

• Used in food fermentation and biodegradable polymer industries.

✅ Correct match: Q–4

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R) Gluconobacter suboxydans → Sorbose (2)

• Gluconobacter suboxydans is an acetic acid bacterium.

• It incompletely oxidizes sugars and sugar alcohols.

• It is a key organism in sorbose production, an intermediate in vitamin C synthesis.

✅ Correct match: R–2

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S) Streptomyces olivaceus → Cobalamin (1)

• Streptomyces species are well-known for secondary metabolite production.

• Streptomyces olivaceus is involved in cobalamin (vitamin B₁₂) production.

• Cobalamin is essential for DNA synthesis and red blood cell formation.

✅ Correct match: S–1

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✅ Final Correct Answer

Option (D)

P–3, Q–4, R–2, S–1

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Introduction

The ability to match the microorganisms with their fermentation products is a core concept in industrial microbiology and biochemical engineering. This type of MCQ is frequently asked in exams like GATE, CSIR-NET, CUET-PG, and university assessments. Understanding which organism produces which metabolite is essential for fermentation technology, industrial applications, and process design.

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Explanation of Microorganism–Product Matching

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Leuconostoc mesenteroides

This lactic acid bacterium is famous for producing dextran, a polysaccharide synthesized from sucrose during fermentation. Dextran has applications in food texture enhancement and plasma volume expanders.

➡ Correct product: Dextran

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Rhizopus oryzae

A filamentous fungus widely used in organic acid fermentation, Rhizopus oryzae efficiently converts carbohydrates into lactic acid, especially under controlled aerobic conditions.

➡ Correct product: Lactic acid

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Gluconobacter suboxydans

This acetic acid bacterium carries out incomplete oxidation reactions. It is industrially important for converting sorbitol into sorbose, a crucial intermediate in vitamin C production.

➡ Correct product: Sorbose

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Streptomyces olivaceus

Members of the Streptomyces genus are prolific producers of antibiotics and vitamins. Streptomyces olivaceus is associated with cobalamin (vitamin B₁₂) biosynthesis.

➡ Correct product: Cobalamin

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Correct Matching Summary

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Final Answer

✅ Option (D): P–3, Q–4, R–2, S–1

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Exam Tip

Dextran → Leuconostoc, Lactic acid → Rhizopus, Sorbose → Gluconobacter, Vitamin B₁₂ → Streptomyces
Memorizing these organism–product pairs helps solve multiple MCQs quickly in fermentation and industrial microbiology.