Temperature Optimization and Inhibition Test of Lactobacillus acidophilus Bacteriocins against Salmonella typhi Bacteria Siska Telly Pratiwi, dr., M.Kes (a*), Muhammad Bagas Aditya (a) dan Endah Hamidah, dr., Sp.PA., M.Kes (b)
a) Department of Microbiology, Universitas Jenderal Achmad Yani
b) Department of Anatomy Pathology, Universitas Jenderal Achmad Yani
Abstract
Typhoid fever is an infection of the digestive tract caused by Salmonella typhi bacteria. Bacteriocin is an antimicrobial protein compound that is bactericidal or bacteriostatic produced by the species group of Lactic Acid Bacteria (LAB). One of the LAB which is a digestive tract microbiota is Lactobacillus acidophilus. Bacteriocin protein have an optimum temperature range to provide antimicrobial effect. The aimed of this study was determine the temperature optimization of L.acidophilus bacteriocins on S.typhi growth. The design of this study was a laboratory experimental using the Kirby-Bauer method. The objects of this study were S.typhi ATCC 6539 and the bacteriocin extract of L.acidophilus ATCC 4356 with a temperature treatment of 40o, 60o, 80o, 100o, and 121oC. The results of research observations were carried out by measuring the diameter of the inhibition zone in each treatment. The inhibition zone diameter in each treatment was compared with the inhibition zone diameter with positive control using chloramphenicol and negative control using aquades. The preliminary test gave positive results in the presence of 3mm diameter inhibition. Bacteriocin sensitivity test to proteolytic enzymes gave negative results. This shows the inhibitory power of the preliminary test formed by the action of bacteriocins. The temperature optimization test for L.acidophilus bacteriocins did not give positive results at temperatures of 40o, 60o, 80o, 100o, and 121oC. This is due to several reasons, namely the storage and McFarland 0.5 standard setting is too small to inhibit S.typhi growth. This is evidenced by the preliminary test without McFarland arrangement which can provide 3mm diameter inhibition. The conclusion of this study is that L.acidophilus bacteriocin can be identified, extracted and inhibited the growth of S.typhi but temperature optimization has not been able to provide results because the storage and use of McFarland standards are too small.
