Bioremediation potential of immobilized Corynebacterium kutsceri in the treatment of tannery industry effluent from Challawa Industrial estate, Kano State, Nigeria

In the present study, bioremediation potentials of indigenous bacteria (Corynebacterium kutsceri) in the treatment of tannery effluent was investigated. Industrial tannery effluent samples from Mamuda Tannery Industries in Challawa Industrial estate, Kano State, Nigeria were collected for a period of six months (August 2017 to January 2018) for the experiment. Bacteria were isolated from the effluents using serial dilution, immobilized on agar-agar and biochemical tests were carried out to identify the bacteria. Different masses (5 g, 10 g, 15 g, 20 g, and 25 g) of the identified bacteria were used in the treatment of 250 mL of the effluents. Temperature, pH, Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Suspended Solid (SS), Total Dissolved Solids (TDS), sulfate, phosphate, nitrate, chloride, and some heavy metals (Cr, Fe, Mn, Ni, Pb, Zn, Cd, and Cu) were determined before and after treatment of the effluents with the bacteria. The pre-treatment analysis showed that the values, 29.50±4.68, and 5.35±1.57, were observed for temperature (OC) and the pH respectively. The levels (mg/L), 26.17±9.49; 3106±2753; 562±482; 444±507; 97.20±146.80; 268.34±411.01; 8.82±34.71 and 22.59±19.64 were observed for BOD, COD, SS, TDS, nitrate, sulfates, phosphate, and chlorides, respectively. The concentration (mg/L) of the heavy metals, before treatment (with the bacteria) were as; Cr (7.528±4.530); Fe (1.263±0.502); Ni (0.023 ± 0.021); Mn (0.277 ± 0.03); Pb (0.304 ± 0.20); Zn (0.058± 0.05); Cd (0.068±0.02) and Cu (0.012 ±0.02). The bacteria were identified to be Corynebacterium kutsceri. The post-treatment analysis showed that the COD (1376±248−2681±867 mg/L) has the highest value while Cu (ND −0.007±0.00 mg/L) has the lowest value. The post-treatment analysis using the different masses of the Corynebacterium kutsceri indicates that there is a great decrease in the levels of the physicochemical parameters and the heavy metals as well when compared with the levels observed at the pre-treatment analysis. The decrease could be attributed to, not only due to the increase in the exact mass of the bacteria but also to the multiplicity in the mass of the Corynebacterium kutsceri which subsequently increases the surface area for the remediation. The average high percentage reduction (70% to 100%) of these parameters and heavy metals implies that the Corynebacterium kutsceri has a higher potential for the treatment of effluents from the textile industries.