Impact of Methylobacterium in the drinking water microbiome on removal of trihalomethanes

Abstract A major class of chlorine disinfection by-products in water treatment and distribution systems is the trihalomethanes. When they occur at high concentration in drinking water they may cause serious problems to human health. Little is known about the capacity of bacterial species that are endemic to drinking water to affect the fate of those chlorination by-products. Methylobacterium species have been previously found to play an important role in the degradation of another major group of chlorine disinfection by-products: the haloacetic acids. Thus, the role that Methylobacterium might play in the concentration of trihalomethanes in drinking water was explored in this study. Concentrations of trihalomethanes were measured in drinking water for different concentrations of Methylobacterium and under different organic matter and chlorine concentrations. The results revealed that when the Methylobacterium DSM 18358 is present in drinking water, even at a low relative abundance of 1%, it plays a key role in decreasing the concentration of trihalomethanes up to 48% from the initial one after 24 h.