Introduction Bacteria : Biochemical properties

Introduction 

Bacteria species can not be distinguished using morphological and cultural characteristics that may show the apparent difference in biochemical reactions. Microbial biochemistry tests shorten the time required to identify microbes, reduce costs, and ensure or enhance the accuracy of identification of an unknown sample. It is the fastest developing trend in microbial identification. In recent years, rapid commercial test kits for anaerobic bacteria have become available.

There a few test that can be done, which are ;

    1) Carbohydrate Test

    2) Catalase Test

    3) Sensitivity to Antibiotic 

Carbohydrate Test

The carbohydrate fermentation test is used to determine whether or not a bacteria can utilize a certain carbohydrate. It tests for the presence of acid and/or gas produced from the fermentation of a single particular carbohydrate.

Observation 

 

Bacteria inside a few types of Carbohydrate

Result

Pseudomonas did not produce bubble and did not change color in both solutions

E-coli did  produce bubble and change color in both solutions

Bacillus did not produce bubble and did not change color in both solutions

Discussion

1. Bacteria that is positive gram staining will not react to the carbohydrate solution 
2. Bacteria that is negative gram staining will react and produce bubble and make the solution brownish

Catalase Test

The catalase test is one of the three main tests used by microbiologists to identify species of bacteria. If the bacteria possess catalase (i.e., are catalase-positive), when a small amount of bacterial isolate is added to hydrogen peroxide, bubbles of oxygen are observed. The catalase test is done by placing a drop of hydrogen peroxide on a microscope slide.

Methodology

1. A microscopic slide was put some of the bacteria colony 
2. A few drops of H2o2 was a drop at the slide to see the reaction 

Observation

Pseudomonas react to the H202

Bacillus react to the H202

Discussion

1. Both of the bacteria react to the H2O2
2. Supposedly only Positive gram bacteria react to hydrogen peroxide while Negative gram bacteria does not react to H202
3. Contamination might occur when we try to smear the bacteria to the slide
4. The bubble is due to catalase react to the bacteria 

Sensitivity of Antibiotic

This test proves different types of bacteria and microorganisms can grow on different antibiotics or sensitive to them. if it is sensitive, it cannot grow in that particular media.

Observation

 Bacillus culture

Penicillium Culture

E-coli Culture

Discussion

1. In Bacillus culture, all antibiotic react however colistin have the least reaction among all
2. In Penicillium culture,  erythromycin and penicillin do not react to Penicillium culture and kanamycin is the most sensitive of all.
3. In E-coli culture, Penicilin does not react while others react prospectively. Kanamycin and erythromycin react the most 
4. This show, different antibiotic react differently in bacteria. with the right kind of antibiotic, it will react the most and prevent from infection.