BACILLUS SUBTILIS

Bacillus subtilis

Bacillus Subtilis

Introduction

Bacillus is a genus of bacteria and rod-shaped Gram positive. The genus Bacillus is part of the division Firmicutes. They are aerobic or strict anaerobic physicians. Forming an under stressful conditions endospore central sheet, which does not deform the structure of the cell unlike the clostridia endospore. This spore form is resistant to high temperatures and chemical disinfectants currents. Most species are positive for the test of catalyze and are saprophytes. They live in soil, sea water and rivers, apart from food contaminated by their presence. Although generally mobile, flagella peritrichous, some species of medical interest are immobile. There are species that produce antibiotics. Bacillus subtilis provides effective control of diseases caused by fungi and bacteria (Noirot, 2007). The biochemical compound in this product combats pathogens by their mode of action. It has wide spectrum of action, foliar and root (Zhou, 2008). Bacillus subtilis is gram-positive bacteria commonly found in soil and contains only a single membrane making it an ideal setting for the secretion of organic molecules.

Gram staining of Eschericia Coli and Bacillus Subtilis

The lab course day the gram staining of Escherichia coli and Bacillus subtilis was carried out. After staining these two species were investigated under the microscope and E. coli was short gram-negative bacterium while B. subtilis was long gram-positive bacterium.

The shape of the colonies of the unknown bacterium and the shape of the unknown bacterium

The unknown bacterium which was incubated in the new agar plate overnight was also investigated under the microscope and it was confirmed that the bacterium was forming tetracocci but the bacterium was not round rather had irregular form or sometimes was a bit elongated in one direction. The drawing of them is presented in the figure 2.

Till the third lab course day the restreaked colonies have grown and merged and the photo of them was taken which is shown in the figure 3.

The colony shape was round and the colony margins were smooth and the colony texture was also smooth.

Gram staining of the Unknown Bacterium

On the forth lab course day the gram staining of this bacterium was performed and the outcome was that it was gram-negative bacterium.

Growth of Escherichia coli in batch culture

The next day the experiment of the growth of E. coli was performed. The collected data are presented in the table 1.

The table 1 was changed so that in the place of the OD600 value the logarithm to the base 10 of the OD600 value was taken and the results were presented in the table 2. This is equivalent to presentation in half-logarithmic manner the only difference is that the Log(OD 600) values are negative. Such representation was chosen because it is easier with a program to find the best fit line to the data and the slope.

Finally, only the points which make line were taken to calculate the slope. These points are presented in the table 3.

The slope is:

k = 0.0050 min-1

Because the number of cells in 1 ml is ...