Abstract:

Objective:The aim of this study is to examine effects of para-aminobenzoic acid (PABA) on the growth ofLactobacillus aci- dophilus(L.acidophilus).Methods:Different concentrations of PABA (10-10~10-3gPL) were separately transferred to the modi- fied Carlsson medium.L.acidophilus(ATCC4356) grew in these Carlsson media. All cultureswere incubated at 37eanaerobi- cally in atmosphere of 80% of nitrogen, 10% of hydrogen, and 10% of carbon dioxide for 48 hours. Absorbance values (K= 540nm) of bacterial suspensions were measured using a spectrometer (UV-1601). Colony forming units (CFU) were obtained by growingL.acidophilusin Carlsson media with different concentration of PABA (10-10~10-3gPL).Results:Different concentra- tions of PABA (10-10~10-4gPL) had different stimulating effects on the growth ofL.acidophilus(P<0.05). But stimulating ef- fects declined, when PABA concentrationwas 10-5gPL, andwhen the concentration of PABA reached 10-3gPL, the stimulating ef- fect disappeared.Conclusion:This study indicates PABA stimulates the growth ofL.acidophilus, and PABA can promote growth ofL.acidophilus.

Key words: Lactobacillus acidophilus, para-aminobenzoic acid, growth