In vitro study of butyric acid deodorization potential by indigenously constructed bacterial consortia and pure cultures from pit latrine fecal sludge

Abstract

The present study aims at developing an e cient bacterial consortium to biodegrade butyric acid, one of the odor-causing compounds that contribute significantly to pit latrine malodors. Six bacterial strains isolated from pit latrine fecal sludge were selected for the study. Nineteen bacterial consortia of di erent combinations were artificially constructed. The individual bacterial strains and bacterial consortia were compared by culturing in mineral salt medium supplemented with 1000 mg/L butyric acid as a sole carbon and energy source at pH 7, 30 C, and 110 rpm under aerobic growth conditions. A co-culture of Serratia marcescens and Bacillus cereus was an e ective bacterial consortium compared to individual component bacterial strains and other bacterial consortia, in which 1000 mg/L butyric acid was completely degraded within 16 h of incubation. A temperature of 30 C and pH 7 were found to be optimum for the maximum degradation for both S. marcescens and B. cereus. The inoculation sizes of 2.0 and 2.5 were optimal for the maximum degradation for B. cereus and S. marcescens, respectively. The study provides insights that will be of substantial help in the development of e ective biological treatment technologies for pit latrine odor to change the pit latrine user community’s and would be users’ perception of pit latrines.