Effects of External Carbon Source Concentration on Sulphate Removal by Selected Bacterial and Fungal species

The aim of this study was to investigate the role of initial external carbon source concentration on sulphate removal by four bacterial and four fungal isolates under shake flask conditions. The test wastewater was filtered and supplemented with sodium acetate as the external carbon source at respective concentrations of 5g/L, 10g/L, 15g/L and 20g/L, before dispensing in 200mL quantity in 250mL capacity conical flasks, sterilised and inoculated with the test microbial isolates. Prior inoculation and at 24h interval, for 96 h for the estimation of sulphate concentration in the wastewater using standard methods. The results revealed remarkable sulphate removal in the absence of the sodium acetate and on its 5g/L addition. An increase in the concentration of the sodium acetate caused a corresponding decrease in the level of sulphate removal. Percentage sulphate removals in presence of the test isolates were observed to range from 47.01 to 57.81%, 18.66 to 51.66%, -1.64 to 11.03%, 5,38 to 22.37% and -3.59 to 5.18%, at sodium acetate concentrations of 0g/L, 5g/L, 10g/L, 15g/L and 20g/L, respectively. This trend was irrespective of the isolates used for investigation. The study was able to provide an insight to the role of carbon concentration on sulphate removal by the test microbial isolates.