Optimization of hemolysin formation in Alcaligenes species isolated from abattoir wastewater samples in Akure, Ondo State, Nigeria

Abstract

Hemolysin is significantly toxic and it is used as a molecular marker for pathogenicity. This study evaluates the conditions for optimal hemolysin production by Alcaligenes faecalis strains isolated from a city abattoir wastewater. The parameters investigated for hemolysin formation were size of the inoculum, initial pH of production medium, bacterial incubation temperature, agitation speed and growth media. Thereafter, the effect by various parameter on the hemolytic activity for the formation of hemolysin were assessed. The genus Alcaligenes was assigned to the test organisms after analyzing their 16S rRNA gene sequence with accession numbers: MF498824, MF498825 and MF498827. Optimum conditions for hemolysin formation in Alcaligenes faecalis strain OS42 were inoculum size of 0.5% (v/v), pH 9, 20 oC, 0 rpm and brain heart infusion broth. Hemolytic activities, 77% and 79% were achieved at 20 h for strains OS42 and OS61, respectively. Cholesterol and ethylenediaminetetraacetic acid did not affect hemolysin formation. This work revealed that the hemolysin formation in Alcaligenes strains was sourced from abattoir wastewater effluent and the effluent was contaminated with pathogenic Alcaligenes strains which is a public health hazard due to their prospective infection to human and animal.