Microbiology Lab Report

Running head : BACILLUS AS THE UNKNOWN

Bacillus as the Unknown Bacteria in Identification of the Unknown

Name of the Student

University /School

Name of Instructor

Course /Subject

Bacillus as the Unknown Bacteria in Identification of the Unknown

Bacteria , even how microscopic they may be are undoubtedly ubiquitous in nature . They have agents of many diseases and the reason for the discovery of vaccines and antibiotics . Nowadays , bacterial identification is a paradigm for microbiologists , food technicians and public health officers . Bacterial identification is a vital role of these groups

of people since these organisms impart diseases to humans and animals alike . It is therefore important to know the identity of the bacteria to test its pathogenic properties and have an immediate action to prevent its spread . Among which are Streptococcus pneumoniae that causes pneumonia and Bacillus anthracis that cause anthrax disease (Anderson , R , 2005

In the foods industry , it is important to determine the genus of the microorganisms that will cause the spoilage of certain foods . In contrast , some of the microorganism such as some strains of Escherichia coli that is mutual dwellers of human gastro-intestinal tracts , which inhibits the growth of other pathogenic microorganism in the gastro-intestinal cavities . Some members of the genus Bacillus is also good spore formers which becomes the basis of sterilization procedures (FAO , 2008 . Hence , determining the identity of the unknown bacteria through laboratory procedures and biochemical tests are important requisites in understanding the properties of different genera of bacteria (Materials and Methods ) In determining the identity of the unknown bacteria assigned , pure culture technique was employed . The mixed culture was streaked in a TSA (Trypticase Soy Agar ) plate and distinct colonies were identified as pure cultures of different unknowns after incubation . In to separate the unknown microorganism into two large subgroups , gram stain technique was used in determining whether the unknowns are gram positive and gram negative bacteria

After grouping the broad categories of the unknown bacteria into two , a separate lactose test was applied in to determine the ability of the bacteria to utilize lactose thereby separating other bacteria from the unknowns . Both gram positive and gram negative bacteria are subjected to lactose test for differentiation . After lactose test in the gram positive category , one bacterium was isolated . Furthermore , a catalase test with the two remaining bacteria was employed in to separate those bacteria that contain the enzyme catalase with that of the bacteria that do have . In the gram negative category , the lactose test separated one bacterium from the three gram negatives . After that Simon citrate utilization test was applied to differentiate the remaining two bacteria . The lactose test , catalase test and Simon citrate test was the biochemical test used to establish the identity of the unknowns

Lactose test is employed to determine whether the unknown bacteria ferment lactose . Durham tube was placed in each test tube containing a lactose medium with an indicator dye that will detect the change in pH through color . Moreover gas formation in the Durham...