Biofilm formation and chlorine resistance of microbial communities in household drinking water system: Preliminary idea of using bacteria to control bacteria

Abstract

Household drinking water system is potentially contaminated by microbial biofilm. Various biofilm properties may result from the community-intrinsic properties of microorganisms. This study investigated biofilm formation and chlorine resistance of six microbial communities in three household pipes (polypropylene random (PPR), stainless steel (SS), and copper). Biofilm biomass was greatest in PPR pipes. The community-intrinsic properties of the same microbial community could be diverse in different pipe materials, which affected biofilm properties. In PPR pipes, microbial communities lacking Bacillus or Acidovorax displayed the greatest biofilm biomass. However, microbial communities without Acidovorax displayed less biofilm biomass in SS and copper pipes. During chlorination, more stable EPS was more protective for the enmeshed bacteria. Community-intrinsic properties helped bacteria resist chlorine. Due to the different community-intrinsic properties, the same multi-species biofilm could display various strengths of chlorine resistance. The chlorine resistance of the microbial community without Acidovorax in SS and copper pipes was better, whereas in PPR pipe was worse. Microbial communities lacking Bacillus exhibited the highest biofilm biomass reduction rate in three pipes, indicating Bacillus might generally enhance chlorine resistance. The findings indicated deeply understanding the role of various bacteria in communities will help to biological control and better develop disinfection strategies.