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

(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

Step-by-Step Matching With Explanation

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

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

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

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

✅ Final Correct Answer

Option (D)

P–3, Q–4, R–2, S–1

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.

Explanation of Microorganism–Product Matching

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

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

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

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

Correct Matching Summary

Final Answer

✅ Option (D): P–3, Q–4, R–2, S–1

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.