**6.4 Isolation and purification**

Nineteen strains have been selected from the available samples, notably:


It is worth noting that more numerous strains have been taken and untreated tannery effluents have been excluded from the test. Morphology, Gram reaction and catalase test findings have been included in **Table 11**. Morphologically different strains have shown same behavior, and rod shape and Gram<sup>+</sup> have been predominant. Bacterial counts executed on mixed wastewater sludges, as well as on treated and untreated tannery effluents, have resulted in 2108, 2108 and 417 CFU/ml respectively.

### **6.5 Attachment test**

This test has consisted of the determination of the relationship between OD600 values and concentration of cells materials per ml of assumed dilution. **Figures 8** and **9** show the relevant spectrophotometric findings. **Table 12** shows the results of the OD550 spectrophotometric findings of the observations on ELISA plates adopted for the attachment test. **Table 12** also shows means and standard deviations related to the 10 times repeated tests for each dilution. The test has revealed an excellent attachment capability of the studied strain.
