Effect of exposure time, bacteria concentration and culture age of escherichia coli and bacillus subtilis on the glass surface

• Main Author: Nasuha, Ibrahim
• Format: Undergraduates Project Papers
• Language: English
• Published: 2014
• Subjects: QC Physics
• Online Access: http://umpir.ump.edu.my/id/eprint/9209/1/Effect%20of%20exposure%20time%2C%20bacteria%20concentration%20and%20culture%20age%20of%20escherichia%20coli%20and%20bacillus%20subtilis%20on%20the%20glass%20surface.pdf; http://umpir.ump.edu.my/id/eprint/9209/

This thesis presents the effect of the bacterial adhesion on the glass surface (hydrophilic surfaces) at different time exposure and bacterial concentration. The ability of Escherichia coli and Bacillus subtilis to attach to the surfaces depends mainly on the interaction of hydrophobic domains. However, E. coli and B. subtilis have evolved in different ways in order to manipulate the hydrophobic effect for their adherence on the solid surface. On the other hand, the surface properties e.g surface charges are inherently important and often regulate the mechanism of the bacteria adhesion. Besides that, adhesions of bacteria were also affected by culture media, exposure time of bacteria on glass surface, age and bacterial concentration. Both bacteria have different surface characteristic which also affect adhesion on the glass surface. Both bacteria were suspended in the phosphate buffer solution (pH 7.1) at different cell concentration (abs). The solution was suspended into glass container containing glass slide. The glass-bacterial solution was shake at 100 rpm and 30⁰C in the incubator shaker and sampling were done at 4 h, 8 h, 12 h and 24 h. From the researches that have been done B. subtilis easily adhere on the glass surface compared to E. coli, with 46.9% reduction in optical density reading observed at 600nm. Bacillus subtilis was exposed for 24 hour at cell concentration 0.8 abs. Meanwhile, E. coli result in less adhesion to the glass surface with only 29.8 % reduction in optical density. Yet, the time of exposure for E. coli was only 12 hour with cell concentration 1.0 abs