Removal of Pathogens (Escherichia coli O157:H7 and Salmonella typhi), and nutrients from wastewater by Lactic Acid bacteria

Outbreaks of various forms of diarrhoea, particularly cholera and typhoid, are a frequent occurrence in low income countries. Poor water sanitation and hygiene practices are frequently implicated for all diarrhoeal out breaks in the low income countries. The present study assessed (i) the probiotic potential of selected strains of lactic acid bacteria in terms of their inhibition activities against Escherichia coli O157:H7 and Salmonella typhi, and the removal of heavy metals in wastewater. The selected lactic acid bacteria had probiotic properties, namely resistance to low pH (pH2 and 3), tolerance to bile salts and sodium chloride, and significant antimicrobial activities against strains of E. coli O157:H7 and S. typhi (p < 0.001). Strains of lactic acid bacteria were shown to modulate the concentration of aqueous Cu, Mn, NH4 + and Zn with a significant net decrease between Day 7 or 10 (p ≤ 0.05). The selected lactic acid bacteria were also shown to deploy biofilms on surfaces of sand particles, which are thought to constitute a mechanism by the lactic acid bacteria to hold and kill E. coli and S. typhi in wastewater. The lactic acid bacteria have exhibited great potential for use in the removal of diarrhoeagenic bacteria and heavy metals from wastewater.