Research Article
Callistus I Iheme, Doris I Uka
Abstract
Introduction: Effects of physico-chemical parameters on microbial dehydrogenases from domestic waste dumpsites were studied. Methodology: The microorganisms (S. aureus, E. coli, P. aeruginosa, C. albicans, T. Mentagrophytes and F. oxysoprium) were isolated from three domestic waste dumps in Owerri metropolis and subculture. Microbial dehydrogenases were extracted with acetone, partially purified by ammonium sulphate precipitation, dialysis, DEAEcellulose column chromatography and Sephadex G200 gel filtration chromatography. Dehydrogenase activity at each stage of purification was assayed with 2,3,5-triphenyltetrazolium chloride (TTC) and the absorbance of the formazan formed was measured and used to ascertain the total dehydrogenase activity. The impacts of effectors (Ca2+, Mg2+, Zn2+, Fe2+ and EDTA, ethanol and butanol) on the microbial dehydrogenase were determined by incubating the partially purified enzyme with the effectors for 30 min at 4°C. Also, the effects of temperature and pH were assessed by varying the temperature and pH ranges from 10°C to 60°C and 2.0 to 8.0, respectively. Results: The specific activities of the enzyme from the microorganisms were 7.10, 7.73, 6.47, 6.26, 9.66 and 10.58 mg Formazan/mg cell dry wt/h, respectively. Calcium ion, Mg2+, ethanol and butanol significantly increased (p<0.05) dehydrogenase activities in all the microorganisms studied while Zn2+, Fe2+ and EDTA decreased the activities. Conclusion: These activators can be harnessed within the recorded optimum temperature and pH ranges to enhance microbial growth; which is essential for the degradation of domestic waste thereby promoting cleaner environment.