Presence of antioxidant materials in bacteria

Fourteen species of gram‐positive and gram‐negative bacteria from nine genera were investigated to determine if they produced compounds that have antioxidant activity. Washed bacterial cells were extracted with methanol for 24 hr. This extract was evaporated to dryness and extracted with benzene. The fractions were added to lard and incubated at 58 C. Antioxidant activity was determined by prolongation of the period required for the initiation of rancidity as measured by changes in peroxide value. The methanol soluble‐benzene soluble fractions ofBacillus cereus, Lactobacillus dextranicum, Micrococcus freudenreichii andSarcina lutea showed considerable antioxidant activity. Methanol fractions of threePseudomonas species showed considerable activity that could not be extracted with benzene. The possibilities of using microbial growth on fats as well as extracts of microorganisms added to fats as antioxidants are discussed.