Read the following passage carefully and answer the given questions.
We use microbes and microbially derived products almost every day. Bacteria called lactic acid bacteria (LAB) grow in milk to convert it into curd. The dough, which is used to make bread, is fermented by yeast called Saccharomyces cerevisiae. Microbes are used to produce industrial products like lactic acid, acetic acid and alcohol, which are used in a variety of processes in the industry. However, certain bacteria, which grow anaerobically on cellulosic material, produce large amount of methane along with \( CO_2 \) and \( H_2 \). These bacteria are collectively called methanogens, and one such common bacterium is Methanobacterium. These bacteria are commonly found in the anaerobic sludge during sewage treatment. Microbes are also used for commercial and industrial production of certain chemicals like organic acids, alcohols and enzymes. Examples of acid producers are Aspergillus niger (a fungus) of citric acid. You are familiar with the commonly used antibiotic Penicillin. Do you know that Penicillin was the first antibiotic to be discovered, and it was a chance discovery? Statins produced by the yeast Monascus purpureus have been commercialised as blood-cholesterol lowering agents. It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.
A boy wants to set curd from milk. Suggest which of the following microbes can be useful for him?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Lactobacillus
Curd is made by lactic acid bacteria (LAB) such as Lactobacillus. They grow in milk and produce acids that coagulate and partly digest the milk proteins. A little curd added to fresh milk works as a starter, and LAB also raise the vitamin B12 content.
Option (4) Lactobacillus — Correct. LAB convert milk into curd.
Note: The passage is taken from NCERT. NTA has put lines of the NCERT text together to make it. Most CUET (UG) questions come straight from NCERT, so study the book line by line, including figures and their titles.