Avatar for Sourav Pan

Sourav Pan

Founder of Biology Notes Online, Biology & Microbiology Educator, M.Sc. in Microbiology
Expertise
Microbiology, Immunology, Cell Biology, Molecular Biology, Genetics, Biotechnology, Biochemistry, Botany, Zoology
Education
University of Calcutta
Profile Last Updated: August 10, 2026

Sourav Pan is the founder and sole author of Biology Notes Online. He holds a Bachelor of Science (B.Sc.) degree and an M.Sc. in Microbiology from the University of Calcutta. He creates educational resources covering microbiology, immunology, biotechnology, genetics, cell biology, botany, zoology, and other life-science subjects.

His goal is to make complex biological concepts easier to understand through well-structured, student-friendly articles based on academic textbooks, peer-reviewed research, and authoritative scientific sources. In addition to writing new content, he regularly reviews and updates articles to improve their accuracy, clarity, and educational value.

Phenylethyl Alcohol Agar – Composition, Preparation, Uses, Limitation

Phenylethyl Alcohol Agar - Composition, Preparation, Uses, Limitation

A selective medium called phenylethyl alcohol (PEA), is used to cultivate Gram positive organisms, especially cocci, in a sample containing pathogens. Phenylethyl alcohol is the active ingredient that inhibits or significantly reduces growth of Gram-negative organisms.

Anaerobic Culture Media – Examples, Definition

Anaerobic Culture Media Examples, Definition

Anaerobic Culture Media used in anaerobic bacteriology may be prepared in a fresh manner or bought from commercial vendors.
Media for anaerobic fermentation that is created in the laboratory should be used within two weeks after the time of preparation, as prolonged storage can degrade the quality of the medium due to peroxide accumulation and dehydration.

Xylose Lysine Deoxycholate (XLD) Agar – Composition, Preparation, Principle, Uses

Xylose Lysine Deoxycholate (XLD) Agar Composition, Preparation, Principle, Uses

Xylose Lysine Deoxycholate agar (XLD) is a selective medium that allows for the isolation and growth of Salmonella and Shigella species using clinical samples or food. Taylor developed XLD Agar to aid in the differentiation, isolation and identification of enteric disease agents and support the growth more specialized enteric organisms. XLD Agar is a well-proven medium that allows the growth of Shigella species. It is also an excellent medium to isolate Salmonella species. It has a pH value of 7.4, giving it a bright pink to red color due to the indicator phenol. 

Mannitol Salt Agar (MSA) – Composition, Principle, Preparation, Results, Uses

Mannitol Salt Agar (MSA)

Mannitol Salt Agar (MSA) is utilized as a differential and selective medium to isolate and detect Staphylococcus aureus in clinical and non-clinical samples. It is recommended for identification and enumeration of coagulase positive Staphylococci that are present in milk, food as well as other specimens. MSA also promotes an increase in the number of particular group of specific bacteria, while limiting the growth of other bacteria.

New York City Agar – Composition, Preparation, Result, Uses

New York City Agar Composition, Preparation, Result, Uses

NYC Agar Base medium was initially created by Fauer, Weisburd and Wilson at the New York City Department of Health to isolate the pathogenic Neisseria strains from human samples. NYC medium, designed primarily to isolate pathogenic Neisseria is also able to support the growth of mycoplasmas with large colonies or mycoplasmas T (Ureaplasma). It is a translucent medium, highly selective, allowing direct microscopic observations and presumed identification of mycoplasmas and Neisseria gonorrhoeae.