A novel strain of the genus
Micrococcus
isolated
from wastewater was studied for resistance to seven heavy
metals and forty antibiotics. Its capacity to accumulate
metal ions was also realized at different pH. The strain
exhibited high minimal inhibitory concentration values for
metal ions tested and resist to 15 antibiotics. The living
cells of the bacterial strain show a largest uptake capacity
at pH 6–8.5 for copper, nickel, and zinc with values
ranging from 51.45 to 83.90 %, 52.59 to 78.81 %, and
59.55 to 78.90 %, respectively. It was also able to absorbed
59.81–80.08 % of chromium and 58.09–79.41 % of cobalt
at pH 7.3–8.5. The maximum lead uptake was obtained at
pH 5.5–8.5 with an amount of 55.28–91.06 %. The significant
absorption of cadmium was shown at pH 6.5 with
38 %. In 25 µg mL
-1 zinc, chromium, and nickel solutions,
dead cells of the isolate were able to biosorbed 20.46,
22.5, and 23.98 µg mL
-1, respectively, after 30 min of
contact. In other solutions with higher concentrations 50
and 100 µg mL
-1, the amount of each metal immobilized
was, respectively, as follows: 38.02 and 90.21 µg mL
-1 for
zinc, 39.78 and 89.23 µg mL
-1 for chromium, and 47.19
and 86.83 µg mL
-1 for nickel. Due to its high-metal
accumulation capacity in aerobic conditions, these Grampositive
bacteria may be potentially applicable in situ
bioremediation of heavy metals contaminating aqueous
systems.
