Biodegradation of butyric acid was investigated in mineral salt medium (MSM) with a novel bacterial strain B6a. The molecular identification based on 16S rRNA sequence analysis revealed the bacterial strain B6a as Serratia marcescen. The bacterial strain was able to grow in the MSM supplemented with 1,000 mgL-1 of butyric acid as a sole source of carbon and energy. At pH 7 and 30 oC under continuous shaking of 110 rpm, 1,000 mgL-1 of butyric acid was completely degraded within 24 h. The modified Gompertz model was used to describe the bacterial growth. These results suggest that the application of Serratia marcescen could be a promising biodegradation strategy for butyric acid in pit latrines.