This study examine the effect of saturated fatty acid content on compression ignition engine performance and emissions. Mixtures of saturated fatty acids with a content of 55 %, 65 %, and 75 % using diesel fuel were evaluated in comparison. For each mixture, different proportions of methyl esters of palm, coconut, neem, mahua, jatropha, and pongamia oil (PONOME) were mixed. At 55 % saturation, the density of fatty acids was 878 - 885, and at 65 % saturation - 869 - 879. At 75 % saturation with fatty acids, the density was 860 - 868. It was found that the viscosity at 65% saturation is 5.04 - 5.37, whereas at 55 % saturation it is 5.13 - 5.56, and at 75 % saturation the viscosity is 4.55 - 7.88. At 75 % saturation, a higher cetane number of 57 - 61 was found. The study showed that all eleven combinations of biodiesel are unique, have excellent fuel characteristics, and emit fewer toxic emissions. It was found that as the percentage of biodiesel saturation increased, NOx emissions decreased and smoke emissions increased.