Lysis of filamentous bacteria by surfactants

Abstract

A microbial substance that lyses filamentous bacteria was obtained. The substance also exhibited some properties of a bio-surfactant. Lysing of filamentous bacteria with synthetic surfactants was also examined. Several synthetic surfactants were found to be capable of lysing filamentous bacteria. Nonionic synthetic surfactants with an HLB of 11-15 were found to lyse type 1701 and type 021N in an activated sludge sampled from a sewage treatment plant. Use of the synthetic surfactant to lyse filamentous bacteria was also demonstrated in a continuous-feed aeration tank, and settleability of sludge was improved. The surfactants did not adversely effect floc-forming microorganisms as evidenced by the high rate of TOC removal. The results indicate that synthetic surfactants can be used to prevent filamentous bulking in the activated sludge process.