Improvement of starter culture using induced aerobic respiration in lactobacillus

Abstract

The Lactic Acid Bacteria (LAB) are used for starter preparation in manufacture of various dairy products such as Dahi, Acidophilus milk, Yogurt, Cheese etc. Certain LAB species can exhibit a dual metabolic life in which they can switch from fermentative mode to aerobic respiration mode when heme or heme and menaquinone is present in the medium, which results not only in high cell number but also resistance against many stress conditions. Improved starter cultures was prepared by inducing aerobic respiration in indigenous Lactobacillus culture isolated from dairy, vegetable samples and compares their rate of acid production with fermentative starter culture as well as evaluate different heme and menaquinone concentration effect on the growth of Lactobacillus culture by spectrophotometrically @ 600 nm. The respiratory starters showed a marked increase in rate of acidification as compared to fermentative starters. Excess heme more than 4 μg/ml concentration was toxic to Lactobacillus culture but increasing menaquinone concentration had no such effect.