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Useful Microorganisms - Lactobacilli

Topics

Introduction
Uses of Lactobacilli
Experiment

Introduction:

Lactobacilli are anaerobic bacteria, meaning they produce energy without requiring oxygen. They are primarily known for their role in fermentation, where they convert lactose (milk sugar) into lactic acid. This process reduces the pH of milk, leading to the coagulation of milk proteins and separating them from other milk constituents. This is how milk transforms into yoghurt, giving it a sour taste due to lactic acid. The low pH also helps destroy harmful microbes in milk, making it safer for consumption.

Uses of Lactobacilli:

Lactobacilli are used in fermenting milk to produce yoghurt, buttermilk, ghee, cheese, shrikhand, and other dairy products.
They are used in the large-scale production of non-dairy products like cider, cocoa, and pickles from vegetables.
Lactobacilli are used in probiotic treatments to alleviate abdominal discomfort, improve digestion, and maintain gut health.
Fermented fodder, made using lactobacilli, is offered to domestic cattle like cows and buffaloes to improve digestion and nutrient absorption.
Lactobacilli fermentation is employed in making some types of bread and in the production of certain alcoholic beverages like wine.
The acidic environment created by lactobacilli fermentation helps preserve foods by preventing the growth of harmful microbes.
Fermented products enriched with lactobacilli are known to improve the bioavailability of certain nutrients.
The low pH resulting from lactobacilli fermentation inhibits harmful microbes, ensuring food safety.

Experiment:

1. Aim: To observe lactobacilli bacteria in fresh buttermilk using a compound microscope.

2. Requirements: fresh buttermilk, glass slide, coverslip, methylene blue stain, compound microscope (10X and 60X objectives), and dropper.

3. Procedure

Place a drop of fresh buttermilk on a clean glass slide.
Add a drop of methylene blue stain to the buttermilk.
Gently smear the mixture using a clean instrument and cover it with a coverslip.
Observe the smear under the 10X objective of a compound microscope.
Switch to the 60X objective for a more detailed view.

4. Conclusion: Under the microscope, blue-stained, rod-shaped organisms moving around were observed. These are lactobacilli bacteria, which are minute, rectangular in shape, and responsible for fermentation in buttermilk.

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