Q.38 Match the downstream processes in Group I with the products in Group II.
Group I Group II
P. Solvent extraction 1. Lactic acid
Q. Protein-A linked affinity chromatography 2. Penicillin
R. Extractive distillation 3. Monoclonal antibody
S. Salting out 4. Lipase
(A) P-2, Q-3, R-1, S-4 (B) P-4, Q-1, R-2, S-3
(C) P-4, Q-1, R-3, S-2 (D) P-2, Q-4, R-1, S-3
Downstream processing recovers and purifies bioproducts from fermentation broth, accounting for 50-80% of total costs in industrial biotechnology. Solvent extraction separates antibiotics like penicillin using organic solvents, while Protein-A affinity chromatography specifically purifies monoclonal antibodies. This MCQ tests critical matching skills for fermentation-derived products central to pharmaceutical biotech.
Technique-Product Matches
Solvent extraction (P): Organic solvent (butyl acetate) extracts penicillin G from acidic fermentation broth, exploiting its solubility shift at pH 2-3.
Protein-A linked affinity chromatography (Q): Bacterial Protein-A binds Fc region of monoclonal antibodies (mAbs), enabling >95% purity in single step for biotherapeutics.
Extractive distillation (R): Reactive distillation with aldehyde extractants converts lactic acid to lactate ester, facilitating purification from dilute aqueous streams.
Salting out (S): Ammonium sulfate precipitation selectively recovers extracellular lipase enzymes based on hydrophobicity differences.
Group II Products
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Lactic acid: Organic acid from Lactobacillus fermentation
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Penicillin: β-lactam antibiotic from Penicillium chrysogenum
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Monoclonal antibody: Immunoglobulin G from CHO/mammalian cell culture
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Lipase: Triacylglycerol hydrolase from microbial sources
Correct Answer
Option (A) P-2, Q-3, R-1, S-4 represents standard industrial bioprocess matching.
| Group I | Technique | Matches | Product | Industrial Application |
|---|---|---|---|---|
| P | Solvent extraction | 2 | Penicillin | Classical antibiotic recovery [60% global production] |
| Q | Protein-A chromatography | 3 | Monoclonal antibody | mAb purification ($200B market) |
| R | Extractive distillation | 1 | Lactic acid | PLA biopolymer precursor |
| S | Salting out | 4 | Lipase | Detergent/biofuel enzyme |
Option Explanations
(A) P-2, Q-3, R-1, S-4: Correct. Solvent extraction standard for penicillin since 1940s; Protein-A gold standard for mAbs; extractive distillation for lactic acid purification; salting-out routine for lipases.
(B) P-4, Q-1, R-2, S-3: Incorrect. Solvent extraction (P-4) unsuitable for lipase (aqueous enzyme); Protein-A (Q-1) doesn’t bind lactic acid; extractive distillation (R-2) mismatches penicillin chemistry.
(C) P-4, Q-1, R-3, S-2: Incorrect. Multiple mismatches: solvent extraction not primary for lipase; Protein-A irrelevant for lactic acid; salting-out ineffective for heat-stable penicillin.
(D) P-2, Q-4, R-1, S-3: Partially correct but wrong. Protein-A (Q-4) doesn’t purify lipases (no Fc region); salting-out (S-3) can’t recover antibodies from complex media.
Bioprocess Engineering Context
Penicillin solvent extraction achieves 90% recovery using dual-phase countercurrent systems. Protein-A chromatography costs $1000-2000/L resin but enables platform purification for 70% of approved mAbs. Extractive distillation solves lactic acid’s azeotrope issue for 100 g/L+ concentrations. Salting-out reduces lipase purification steps from 5 to 2, cutting costs 40%. These techniques optimize your fermentation processes for industrial-scale enzyme/antibiotic production.
