Q.12
Match the entries in Group I with that in Group II

Group I

1. Pectinase

2. Xylanase

3. Cellulase

4. Enzymes

Group II
P) In paper and pulp processing
Q) Delignification
R) Gluten complex reduction
S) Improve mineral availability
T) Phosphorolization

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

The correct matching is: P‑4, Q‑1, R‑2, S‑3, so the right option is (A).​​

Introduction

Understanding the industrial applications of enzymes like phytase, xylanase, laccase and bromelain is essential for solving Group I–Group II biotechnology MCQs in CSIR NET and GATE Life Sciences. This article explains the correct matching pattern and analyses every option, linking each enzyme to its major commercial use in food and paper industries.​

Step‑by‑step matching of Group I and II

Group I enzymes

• P) Phytase

• Q) Xylanase

• R) Laccase

• S) Bromelain

Group II applications

1. Paper and pulp processing

2. Delignification

3. Gluten complex reduction

4. Improve mineral availability

5. Phosphorylation

Phytase (P) → improve mineral availability (4)

• Phytase hydrolyses phytic acid (myo‑inositol hexakisphosphate) in cereals and oilseeds, releasing bound phosphorus and minerals such as iron, zinc and calcium.​

• This action improves mineral availability and bioaccessibility in animal feed and human foods, so P correctly matches with 4.​

• “Phosphorylation” (5) is incorrect because phytase dephosphorylates phytate; it removes phosphate groups rather than adding them.​

Xylanase (Q) → paper and pulp processing (1)

• Xylanase hydrolyses xylan, a major hemicellulose in plant cell walls, and is widely used in the pulp and paper industry to boost bleaching and reduce chlorine‑based chemicals.​

• Pretreatment of kraft pulp with xylanase enhances pulp paper and pulp processing performance by improving bleachability and pulp brightness, so Q correctly matches with 1.​

• Although xylanase indirectly facilitates removal of lignin, the specific term “delignification” in this question is reserved for laccase, which acts more directly on lignin.​

Laccase (R) → delignification (2)

• Laccase is a multicopper oxidase that oxidizes phenolic lignin units and is used for delignification and biobleaching of kraft pulps.​

• In pulp and paper mills, laccase (often with mediators) reduces lignin content, brightens pulp, and decreases chlorine dioxide usage, so R correctly matches with 2.​

Bromelain (S) → gluten complex reduction (3)

• Bromelain is a proteolytic enzyme from pineapple stems and fruits that hydrolyses peptide bonds in proteins.​

• In baking, bromelain is used to break down gluten proteins and reduce allergenic gluten epitopes, effectively causing gluten complex reduction, so S correctly matches with 3.​

Why each option (A–D) is right or wrong

Let the mapping format be (P, Q, R, S):

• Option (A) P‑4, Q‑1, R‑3, S‑5

  • P‑4 is correct: phytase → improve mineral availability.​

  • Q‑1 is correct: xylanase → paper and pulp processing.​

  • R‑3 is wrong: laccase is not primarily used for gluten complex reduction; its main industrial role here is delignification in pulp.​

  • S‑5 is wrong: bromelain does not catalyse phosphorylation; it is a protease acting on peptide bonds.​

  • Because two pairings are wrong, option (A) is incorrect.

• Option (B) P‑4, Q‑1, R‑2, S‑3

  • P‑4: phytase → improved mineral availability (correct).​

  • Q‑1: xylanase → paper and pulp processing (correct).​

  • R‑2: laccase → delignification (correct).​

  • S‑3: bromelain → gluten complex reduction (correct).​

  • All four matches are correct; therefore this is the right option.

• Option (C) P‑5, Q‑4, R‑5, S‑2

  • P‑5 is wrong because phytase dephosphorylates phytic acid instead of performing phosphorylation.​

  • Q‑4 is wrong since xylanase does not improve mineral availability; its key role is in pulp bleaching and, secondarily, feed digestibility.​

  • R‑5 is wrong because laccase catalyses oxidation and polymerization of phenolics, not phosphorylation.​

  • S‑2 is wrong because bromelain targets protein networks like gluten, not lignin for delignification.​

• Option (D) P‑5, Q‑1, R‑2, S‑3

  • Q‑1, R‑2 and S‑3 are individually correct matches.​

  • However, P‑5 remains wrong for the same reason as in option (C) (phytase is not a phosphorylation enzyme), so the whole option becomes incorrect.​

Key exam takeaways

• Phytase breaks down phytic acid in plant materials to improve mineral availability, particularly phosphorus, iron and zinc, in feed and food.​

• Xylanase is a hemicellulase crucial for paper and pulp processing, enhancing pre‑bleaching and reducing chlorine‑based chemicals.​

• Laccase is a lignin‑degrading oxidase used in delignification and biobleaching of kraft pulps in eco‑friendly paper manufacture.​

• Bromelain is a protease employed in baking and food processing for gluten complex reduction and tenderization by hydrolysing protein networks.​