Antimicrobial Effect of Coagulant Protein Purified from Vigna Unguiculata Seed and Citrus Fruit Juice on River Water Bacteria

Abstract

Antibacterial effect of Vigna unguiculata coagulant proteins and Citrus fruit juice (CFJ) on bacterial strains isolated from Ruvu River at Mlandizi, in Tanzania was studied. Out of 126 isolated strains 60 were characterised by morphological, biochemical and 16s rRNA gene sequence analysis. A group of strains were identified either as Acinetobacter, Pseudomonas Vibrio, Aeromonas or Bacillus spp. Coagulant proteins of V unguiculata (VUP) seeds were purified by ion exchange chromatography. Flocculation studies showed that, VUP and CFJ aggregate both Gram-positive and Gram-negative bacteria.  Growth studies revealed that minimum inhibitory dosages of VUP was between 0.38 and 0.75 mg/L while for CFJ was between 0.2  and 0.5%,  and growth inhibition occurred within 2 to 4 hr of incubation. The VUP and CJF are suitable for simultaneous coagulation and disinfection of drinking water in poor communities.