Q.26 Match the commercial microbial sources in Group I with the products in Group II.
Group I Group II
P. Corynebacteriumlilium 1. 2,3-Butane di-ol
Q. Klebsiellaoxytoca 2. Poly-β-hydroxybutyric acid
R. Aspergillusniger 3. Glutamic acid
S. Alcaligeneseutrophus 4. Citric acid
(A) P-3,Q-1,R-2,S-4 (B) P-3,Q-1,R-4,S-2
(C) P-1,Q-3,R-2,S-4 (D) P-1,Q-3,R-4,S-2
Correct Answer: (B) P-3, Q-1, R-4, S-2. Corynebacterium lilium produces glutamic acid, Klebsiella oxytoca yields 2,3-butanediol, Aspergillus niger generates citric acid, and Alcaligenes eutrophus synthesizes poly-β-hydroxybutyric acid (PHB). This matching reflects key industrial microbiology applications in biotechnology.
Microbial Sources Overview
Group I lists bacteria and fungi used in commercial fermentation for high-value products. These organisms leverage metabolic pathways optimized through strain engineering for scalable production. Glutamic acid, 2,3-butanediol, citric acid, and PHB serve food, chemical, and biopolymer industries.
Correct Matching Explanation
P. Corynebacterium lilium → 3. Glutamic acid. This bacterium excels in glutamic acid overproduction via amplified glutamate dehydrogenase and reduced α-ketoglutarate dehydrogenase activity, yielding up to 100 g/L for MSG manufacturing.
Q. Klebsiella oxytoca → 1. 2,3-Butane di-ol. Klebsiella oxytoca ferments glucose to 2,3-butanediol through mixed-acid pathways, achieving titers over 100 g/L under microaerobic conditions for biofuel and chemical precursors.
R. Aspergillus niger → 4. Citric acid. Aspergillus niger dominates citric acid production (over 2 million tons annually) via enhanced TCA cycle flux and pyruvate carboxylase overexpression on molasses substrates.
S. Alcaligenes eutrophus → 2. Poly-β-hydroxybutyric acid. Now known as Cupriavidus necator, this hydrogen-oxidizing bacterium accumulates PHB up to 80% of dry cell weight as intracellular granules for biodegradable plastics.
Incorrect Options Analysis
Option (A) P-3, Q-1, R-2, S-4 mismatches R (Aspergillus niger to PHB, incorrect as fungi rarely produce polyhydroxyalkanoates) and S (Alcaligenes eutrophus to citric acid, incorrect as it favors autotrophic PHA synthesis).
Option (C) P-1, Q-3, R-2, S-4 wrongly assigns P to 2,3-butanediol (glutamate specialist) and Q to glutamic acid (butanediol producer), with further PHB-citric acid errors.
Option (D) P-1, Q-3, R-4, S-2 swaps P and Q products, inverting Corynebacterium’s glutamic acid role and Klebsiella’s diol pathway.
Industrial Biotechnology Relevance
These pairings highlight strain selection in bioprocess engineering, where Corynebacterium and Klebsiella use Coryneform/Enterobacterial metabolism, Aspergillus employs fungal submerged fermentation, and Alcaligenes relies on PHA synthase genes for polymer accumulation. Genetic tweaks like plasmid-based pathway engineering boost yields for sustainable chemical production.
