Invitro optimal time and pH for staphylococcus aureus absobtion and disabsorption by bentonite.

Bentonite is known as an absorbent and effective factor in separating and binding heavy metals, drugs, bacteria and other toxins from the body. In this study, the effect of changes in pH (3, 4 and 5) on the adsorption and desorption of Staphylococcus aureus to sodium bentonite was investigated. In addition, adjacent to sodium bentonite with Staphylococcus aureas and direct culture and count of bacteria, Reducing bacteria were shown at different times in the presence of bentonite. Firstly, diluted bacteria ( 1/10) were prepared and autoclaved , added to bentonite samples, and pH adjusted at 3,4 and 5 with HCl and NaOH. After the required time, samples centrifuged and were read by spectrophotometer. Supernatant OD showed initial absorption and sediment OD showed desorption. The results show that, Up to pH 4 , the relation between pH and bacterial absorption to bentonite not significant , but in pH 5 was significant(p0.05). So absorbed was significantly decreased with increasing pH, desorption to pH 5 decreased, but not significantly. In other words, the reduced absorption of bacteria to bentonite with increasing pH, was a linear diagram. There was no significant correlation between pH and time. In the second, S. aureus in BHI medium were cultured for 24 h in 37 c. Then bentonite adjacent to the bacteria at 0, 30, 60 and 90 minutes, and the mixture of bacteria and bentonite were cultured on plate count agar for the total bacterial count. Changes were recorded at each stage. Analysis of variance was performed using a Linear components and deviation and results showed that For the amount of bacteria and colonies is a significant difference between deviation from linear and Linear component. Compared with Duncan' s test showed that in 90 minutes, colonies and bacteria have reduced significantly ( been almost zero). Bacterial count at 60 minutes was more than at 30 minutes. But this increase is not significant (p0.05). Average multiple comparisons with Duncan's test showed that between the times of 30 and 60 was not significantly different from the effect of bentonite to remove bacteria but the difference was significant between 90 minutes and other times (p0.05). Key words:Bentonite,staphylococcus aureus,pH,time, absorbtion,Total count