Question

What procedure did you follow to observe lactobacillus bacterium in the lab?

Answer 1

Hint:- Bacteria are prokaryotic microscopic organisms that are single celled. They are known to be present in different types of habitats and even in the extreme ones also. The bacteria are also utilized in the processing of food products chiefly the milk products such as curd, cheese, butter etc. They are also used for the process of fermentation in the food and beverage industry.

Complete step-by-step solution:-
The lactobacillus bacteria belongs to the genus of aerotolerant anaerobic group. They are Gram- positive bacteria and are rod-shaped. They are known as bacillus due to their rod-shaped cell. They do not form spores and are a major part of the lactic acid group producing bacteria or lactic group bacteria. They are associated with the process of fermentation and convert the sugars into lactic acid.
It is found in a form of mutualism with humans and is found in the important organs such as the digestive system, urinary system and the genital system. In the digestive system, they grow as an important microbiota. Lactobacillus bacteria is the most common probiotics or live microorganism that is found in foods such as curd and yoghurt. It is known to help in the treatment of diarrhea, vaginal infections as well as skin disorders. These bacteria can be observed by preparing a slide or smear by using a preparation of curd or yoghurt in a step wise procedure. For this process, first of all we take a small amount of curd as a starter and mix it with a bowl of milk. The curd is used as a starter to start the cuddling of the milk by the cation of the bacteria. It is then allowed to settle for sometime in a warm place or in an incubator. After the formation of curd, a little amount of curd is diluted and a few drops of this preparation is taken on a slide. It is allowed to dry out and then it is stained with safranin or methylene blue. The bacteria are then seen under the microscope.
The bacteria appear as rod-like cells either individuals or in clusters. If the slide is treated with methylene blue the bacterial cells take up a bluish colour. Some other rounds or cocci can also be observed in pairs, isolated or in clusters.

Note:- The lactobacillus bacteria are found in the curds and yoghurts and cause coagulation of milk due to the conversion of sugars into lactic acid through the process of fermentation. The bacteria can be easily seen by preparing a smear or slide of diluted curd and then staining it with safranin or methyl blue. Lactobacillus bacteria can be seen as rod shaped cells.