Isolation and Morphological Unknown Report (10 points) Due: June 24, 2021
Name of the student:
Unknown Mix #: 10 (Bacillus polymyxa + Serratia liquefaciens)
1. Isolation Technique used to purify the two bacteria: _
Since Bacillus polmyrxa is gram positive bacterium and Serratia liquefaciens is a gram negative
bacterium, gram stain technique is use to purify the two bacteria. Gram stain is a popular method of
measuring the chemical composition of the bacterial cell wall. Depending on its composition, the
cell wall can stain positively or negatively.
____________________________________________________________
2. Colonial characteristics used to differentiate the two bacteria:
_ Bacillus polymyxa makes pale agar colonies. It displays broad, flat non-selective medium colonies.
Often they are beta-hemolytic. It differs from Serratia liquefaciens as their colonies often seem opaque,
somewhat iridescent, white, pink, magenta, or red. Cultures can create two sorts of scents, a urinary
smell of fish or a potato-like musty smell.
3. Stock and working culture preparation:
Inoculation steps should be followed overnight before liquid culture.
Incubation - at 33-37 degrees Celsius for 18-48 hrs.
Isolation- separation of strains.
Inspection- Inspection of the bacteria under a microscope.
Identification- identification of bacteria on basis of characters and shape.
Bacterium A Bacterium B
Name of Paenibacillus polymyxa, also known as Serratia liquefaciens
Bacterium Bacillus polymyxa
Gram Stain Gram-Positive and stain purple Gram-negative and stain pink.
Shape Rods. The vegetative cells are straight, Straight rods with rounded ends
circular or quadratic rods.
Name of the student:
Unknown Mix #: 10 (Bacillus polymyxa + Serratia liquefaciens)
1. Isolation Technique used to purify the two bacteria: _
Since Bacillus polmyrxa is gram positive bacterium and Serratia liquefaciens is a gram negative
bacterium, gram stain technique is use to purify the two bacteria. Gram stain is a popular method of
measuring the chemical composition of the bacterial cell wall. Depending on its composition, the
cell wall can stain positively or negatively.
____________________________________________________________
2. Colonial characteristics used to differentiate the two bacteria:
_ Bacillus polymyxa makes pale agar colonies. It displays broad, flat non-selective medium colonies.
Often they are beta-hemolytic. It differs from Serratia liquefaciens as their colonies often seem opaque,
somewhat iridescent, white, pink, magenta, or red. Cultures can create two sorts of scents, a urinary
smell of fish or a potato-like musty smell.
3. Stock and working culture preparation:
Inoculation steps should be followed overnight before liquid culture.
Incubation - at 33-37 degrees Celsius for 18-48 hrs.
Isolation- separation of strains.
Inspection- Inspection of the bacteria under a microscope.
Identification- identification of bacteria on basis of characters and shape.
Bacterium A Bacterium B
Name of Paenibacillus polymyxa, also known as Serratia liquefaciens
Bacterium Bacillus polymyxa
Gram Stain Gram-Positive and stain purple Gram-negative and stain pink.
Shape Rods. The vegetative cells are straight, Straight rods with rounded ends
circular or quadratic rods.
