Positive bacillus

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Morphological Characteristics
Bacteria comes with different shapes and forms and different genera comes with their specific shapes and sizes. The shapes are hard to determine with unaided eye though, a clear distinction can be made with a microscope. Bacteria comes with fie destine shapes; the rod shape (bacilli), corkscrew (spirochaetes), spherical (cocci), comma shape (vibrio) and spiral (spirilla)In our experiment, we observed rod-shaped bacteria indicating the presence of bacteria from bacilli genus
Colonial morphology
To further rule out more gram-positive bacteria a starch test is carried out on the colonies. Starch test involves putting the bacteria colonies in a favorable growth medium. Starch is essential for some bacteria growth though starch molecules are too large to penetrate through their cell walls. Therefore, the bacteria used another effective way to digest the adjacent starch molecules by secreting enzymes that digest starch into smaller particles that can penetrate through their cell walls. Glucosidase and amylase are enzymes the bacteria use to hydrolyze starch. In this experiment, the blood agar is used as a source of starch and iodine is added into the solution with the bacteria colony. Depending on the concentration of starch in the solution iodine turns black blue or purple. From the experiment, the areas surrounding the bacteria colonies turned from deep blue to pale yellow indicating the presence of bacteria that digest starch.

Members of bacilli genus secrete the enzymes and thus can digest starch. In this experiment, blood agar is used since it provides an enriched growth medium for the bacteria and it is not selective thus cannot inhibit the growth of certain microbe species.
Biochemical test
Further, the catalase test is used to rule out more bacteria. The catalase test is a method used to establish the presence of catalase enzyme that has an effect of neutralizing hydrogen peroxide (Hemraj, Sharma, & Gupta 6). Hydrogen peroxide solution has a high bactericidal effect and often used as a sterilizer in most settings. This test is mostly used to differentiate the presence of genera streptococci and staphylococci. The enzyme catalase neutralizes hydrogen peroxide by breaking it down to produce water and oxygen. The reaction involves the production of bubbles in the solution upon the introduction of hydrogen peroxide. A solution with bacteria colonies which can produce catalase enzyme produces bubbles resulting from the oxygen produces. The solution in our experiment produced bubbles rapidly indicating the presence of bacteria that secrete catalase enzyme. Members of Streptococci genus do not produce catalase enzyme and thus are ruled out from the experiment.
The experiments to identify the bacteria species pointed out that the specimen contained gram-positive bacillus bacteria. Gram-positive bacteria have thick outer peptidoglycan which retains the crystal violet stain. Gram-negative bacteria peptidoglycan layer is thinner and located beneath a thick liposaccharide and protein layer which covers the bacteria (Hemraj, Sharma, &Gupta 4). Peptidoglycan is a polymer made up of amino acids and sugars that are crossed linked to form a rigid cell wall. The thick liposaccharide outer membrane present in gram-negative is responsible for their more resistance to antibiotics. The alcohol solution used is able to decolorize the gram-negative bacteria outer membrane and since they have a thinner peptidoglycan layer; they assume a pink or red color. From the experiment, the crystal violet strain retained after decolonization indicates the presence of gram-positive bacteria.

Work Cited
Hemraj, Vashist, Sharma Diksha, and Gupta Avneet. “A review on commonly used biochemical test for bacteria.” Innovare J Life Sci 1.1 (2013): retrieved from https://pdfs.semanticscholar.org/c337/57cf11e9bf24cce9e4a29a69521e21c877a9.pdf