Sourav Pan

Academic Writer, Microbiology Specialist | M.Sc. Microbiology, Calcutta University, Founder of Biologynotesonline.com

Sourav is the founder and sole author of Biology Notes Online. He holds a Master’s degree in Microbiology from Calcutta University and has over 5 years of experience in academic writing, life science content creation. His content reflects hands-on lab expertise, deep subject knowledge, and a strong passion for simplifying biology for students. Whether it’s genetics, microscopy, or metabolic pathways — Sourav explains it in a way that’s accurate, exam-focused, and easy to remember. He regularly updates and fact-checks all the material published on this site, ensuring students get trustworthy and updated biology notes with references to real scientific sources.

Microdase Test – Principle, Procedure, Result, Uses

• Published on January 2, 2026 • 8 min readby Sourav Pan

The oxidase enzyme is a key factor in distinguishing Staphylococcus from Micrococcus, and the Microdase Disk is a reagent-impregnated disc recommended for use in qualitative procedures.

API (Analytical Profile Index) 20E Test Result, Principle, Procedure

• Published on January 1, 2026 • 15 min readby Sourav Pan

What is API (Analytical Profile Index) 20E Test? The API (Analytical Profile Index) 20E test is a standardized biochemical identification system used for the identification of Enterobacteriaceae and other non-fastidious Gram-negative rods. It is developed as a miniaturized system where a number of biochemical reactions are carried out simultaneously in a single plastic strip. It … Read more

Novobiocin Susceptibility Test – Principle, Procedure, Results

• Published on December 31, 2025 • 14 min readby Sourav Pan

The novobiocin (antibiotic) differentiation disc can be used in the Novobiocin Susceptibility Test to help make a preliminary distinction between Staphylococcus saprophyticus and other coagulase-negative staphylococci (CoNS) in clinical (urinary) specimens.

Pyruvate Broth Test – Principle, Purpose, Procedure, Result

• Published on December 29, 2025 • 8 min readby Sourav Pan

Pyruvate Broth Test is a biochemical test that is used in microbiology for identification and differentiation of certain bacteria. It is mainly used for differentiating species of Enterococcus group. It is the process in which ability of organism to utilize sodium pyruvate as a sole source of energy is determined. The medium used in this … Read more

ONPG Test – Principle, Procedure, Result, Uses

• Published on December 27, 2025 • 11 min readby Sourav Pan

o-Nitrophenyl-b-D-Galactopyranoside (ONPG) Test Principle, Procedure

The o-Nitrophenyl-β-D-Galactopyranoside (ONPG) test is a biochemical test used for the detection of the enzyme β-galactosidase in bacteria. It is mainly applied for differentiating late lactose fermenting organisms from non-lactose fermenters. It is based on the ability of the organism to hydrolyse a synthetic lactose analogue when the required enzyme is present. The test is … Read more

Salt Tolerance Test – Principle, Purpose, Procedure, Result

• Published on December 26, 2025 • 15 min readby Sourav Pan

The ability to develop in the presence of varying concentrations of sodium chloride (NaCl) has been used to distinguish between various bacteria.

Sulfur Reduction Test – Principle, Purpose, Procedure, Result

• Published on December 26, 2025 • 17 min readby Sourav Pan

The Sulfur Reduction Test is the biochemical procedure that is used to detect whether a microorganism is capable of reducing the sulfur-containing compounds to produce hydrogen sulfide (H₂S). It is the process which mainly helps in identifying members of Enterobacteriaceae where some bacteria like Salmonella, Proteus and Citrobacter are able to form the gas during … Read more

Growth at 42 Test – Principle, Procedure, Result, Uses

• Published on December 25, 2025 • 13 min readby Sourav Pan

Growth at 42 Test - Growth of Non Fermentative Bacteria at 42°C

Growth at 42°C test is a physiological test used in microbiology for the identification and differentiation of certain non-fermentative Gram-negative bacteria. It is the process where the organism is tested for its ability to grow and survive at a higher temperature of 42°C. This test is mainly applied for the differentiation of Pseudomonas aeruginosa from … Read more

MRS Broth Test – Principle, Procedure, Results,Uses

• Published on December 25, 2025 • 15 min readby Sourav Pan

Lactobacillus MRS Broth Test - Principle, Procedure, and Results

The MRS formulation was made by de Man, Rogosa, and Sharpe to replace a variable product (tomato juice) and give lactobacilli in general a good place to grow.

Lysine decarboxylase test – Principle, Procedure, Result, Uses

• Published on December 24, 2025 • 10 min readby Sourav Pan

Lysine decarboxylase test relies on the capability of certain bacteria to degrade L-lysine into caverine after the release of carbon dioxide.