ariyo oludotun soyege applied and environmental microbiology research group, department of biochemistry and microbiology, university of fort hare, alice, south africa adedayo olajide ajayi applied and environmental microbiology research group, department of biochemistry and microbiology, university of fort hare, alice, south africa elvis ngwenya applied and environmental microbiology research group, department of biochemistry and microbiology, university of fort hare, alice, south africa albert kotze basson department of biochemistry and microbiology, university of zululand, kwadlangezwa, south africa. anthony ifeanyin okoh applied and environmental microbiology research group, department of biochemistry and microbiology, university of fort hare, alice, south africa; applied and environmental microbiology research group, department of biochemistry and microbiology, university of fort hare, alice, south africa. tel: +27-406022365; fax: +27-866286824