Screening for microorganisms converting stearic acid to form new compounds was conducted. Pseudomonas cepacia A-1419 isolated from soil effectively produced two compounds showing strong ultraviolet absorption when the resting cells were incubated with stearic acid. The products were isolated, and identified as (Z)-dec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (Product 1) and (Z)-dodec-3-ene-1,3,4-tricarboxylic acid 3,4-anhydride (Product 2) by infrared, mass, and nuclear magnetic resonance spectroscopies, and elemental analysis. Products 1 and 2 were produced from stearic acid at conversion rates of about 18 and 32%, respectively.