STUDY MATERIAL · GATE BT
GATE Bioprocess Engineering previous year questions and notes
Fundamentals of Biological Engineering, also known as Bioprocess Engineering. Every Fundamentals of Biological Engineering question from 7 GATE papers (2019–2026), solved step by step and checked against the organising institute’s official answer key — with notes for each topic, a formula sheet and practice questions.
- previous-year questions
- 86previous-year questions
- worked solutions, checked against the key
- 85worked solutions, checked against the key
- GATE papers, 2019–2026
- 7GATE papers, 2019–2026
- topics with notes
- 8topics with notes
TOPICS
Eight topics, in the order they are taught
Cut from the official GATE 2027 syllabus. Each topic has notes, the formulas you need, every previous-year question on it with a checked solution, and practice questions.
- TOPIC 01
Reaction and enzyme kinetics: rate laws, Michaelis-Menten and inhibition
Reaction kinetics expresses the rate of a conversion as a function of concentration and temperature.
9 previous-year questions · 14 marks · 5 practice
- TOPIC 02
Ideal reactors: batch, mixed flow and plug flow
Ideal reactors are the three limiting mixing patterns: the closed, well-mixed batch vessel, the continuous stirred tank (mixed flow, CSTR) and the plug flow tubular reactor (PFR).
2 previous-year questions · 4 marks · 6 practice
- TOPIC 03
Enzyme immobilisation and diffusion effects
Immobilising an enzyme on or inside a solid support lets it be retained, reused and run continuously, but substrate must then cross a liquid film and often diffuse through pores before it reacts, so the measured rate reflects a competition between reaction and mass transfer.
2 previous-year questions · 4 marks · 5 practice
- TOPIC 04
Cell growth, substrate utilisation and product formation
Cell growth kinetics describes how fast a culture grows, how much substrate it uses and how much product it makes.
24 previous-year questions · 36 marks · 6 practice
- TOPIC 05
Batch, fed-batch and continuous bioreactors, and scale-up
A bioreactor can be run as a batch, as a fed-batch or continuously (a chemostat).
24 previous-year questions · 45 marks · 7 practice
- TOPIC 06
Media formulation and sterilisation
Media formulation is the design of a growth medium that supplies every element, energy source and growth factor a cell needs, in the right amounts, followed by optimisation of the recipe by statistical experimental design; sterilisation then removes contaminating organisms from that medium and from the aeration air before the fermentation starts.
7 previous-year questions · 12 marks · 6 practice
- TOPIC 07
Downstream processing: filtration, centrifugation, chromatography, extraction
Downstream processing is the chain of separation steps that takes a product from the fermentation broth or cell mass to the required purity and final form: solid-liquid separation, cell disruption, concentration, high-resolution purification and drying.
9 previous-year questions · 12 marks · 7 practice
- TOPIC 08
Measurement, dynamics and process control
Process control keeps a bioreactor's temperature, pH, dissolved oxygen, pressure, level and flows at their set points.
9 previous-year questions · 16 marks · 6 practice
WHERE THE QUESTIONS FALL
86 questions, by topic and year
Counts across the BT papers of each year. A count of what was asked, not a forecast of what will be. The topic tags are IAE’s reading of each question, and every question links back to its paper.
| Topic | 2019 | 2020 | 2022 | 2023 | 2024 | 2025 | 2026 | Total |
|---|---|---|---|---|---|---|---|---|
| Enzyme kinetics | · | · | 2 | 2 | 1 | 1 | 3 | 9 |
| Ideal reactors | · | · | 1 | · | · | · | 1 | 2 |
| Immobilisation | · | · | 1 | · | · | 1 | · | 2 |
| Growth kinetics | 5 | 2 | 7 | 1 | 4 | 3 | 2 | 24 |
| Bioreactor operation | 3 | 2 | 3 | 2 | 7 | 2 | 5 | 24 |
| Upstream | 1 | · | 2 | · | 2 | · | 2 | 7 |
| Downstream | 1 | 2 | 1 | 1 | 1 | 2 | 1 | 9 |
| Process control | 2 | · | 1 | 1 | 1 | 2 | 2 | 9 |
The 2018 paper is not included: the only copy we could find carries a coaching institute's watermark, so its crops cannot be published. The hosted 2021 file is an image scan with no text layer and no key. BT 2019 is taken from IIT Madras's own copy of the paper and key (via the Internet Archive).
How we check solutions: editorial standards.
Bioprocess Engineering formulas by topic
Preparing in Kolkata? See IAE Academy’s GATE BT coaching.
THE OFFICIAL SYLLABUS
What each paper lists under Fundamentals of Biological Engineering
Verbatim from the GATE 2027 syllabus PDF: BT Section 4, “Fundamentals of Biological Engineering”; the elision (…) drops a parenthetical of design examples and case studies. Only the Biotechnology paper lists this section.
GATE BT
Bioreaction Engineering: Rate law, zero and first order kinetics; (More advanced kinetic models, including Michaelis-Menten kinetics for enzyme reactions. Inhibition kinetics: Competitive, non-competitive, and uncompetitive inhibition in enzyme catalysis); Ideal reactors - batch, mixed flow and plug flow; Enzyme immobilization, diffusion effects - Thiele modulus, effectiveness factor, Damkoehler number; Kinetics of cell growth, substrate utilization and product formation; Structured and unstructured models; Batch, fed-batch and continuous processes; Microbial and enzyme reactors; Optimization and scale up … Upstream and Downstream Processing: Media formulation and optimization; Sterilization of air and media; Filtration - membrane filtration, ultra filtration; Centrifugation - high speed and ultra; Cell disruption; Principles of chromatography - ion exchange, gel filtration, hydrophobic interaction, affinity, GC, HPLC and FPLC; Extraction, adsorption and drying; Measurement devices; Valves; First order and second order systems; Feedback and feed forward control; Types of controllers – proportional, derivative and integral control; Tuning of controllers.
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