Studies on Probiotic Strains from Fermented Foods
Malnutrition is a huge complex problem in developing nations with special reference to South Asia. Ethnically accepted fermented food and beverages, if designed properly, can potentially solve the problem in two ways: providing crucial nutrition and compete out the gut infection. We aim to develop probiotic strains from those food and drinks which are popular and economically affordable in Kerala. Lactobacilli are the most prominent group of bacteria used in probiotic formulations which are isolated in a selective media called MRS. Our objective is to isolate potential probiotic strains in MRS media from popular affordable food/beverages and compare with established probiotic strains like Bacillus clausii with respect to their probiotic attributes. The number of MRS positive colonies was counted in pickles from beetroot, mango, lemon, tomato, and drinks from toddy (Kerala ethnic alcoholic drink), arishtam (Ayurvedic alcoholic drink) and wine. Pickles from beetroot showed highest count. B. clausii , an endospore forming bacterium showed morphological variations during revival and it was found to be sensitive against many antibiotics unlike the reported resistance against many antibiotic as reported in the literature. Our isolates were tested against five different classes of antibiotics. Both B. clausii and isolate type 1 showed high sensitivity against chloramphenicol and comparatively less sensitive to tetracycline whereas isolate type 2 showed resistance against four classes of antibiotics including chloramphenicol and tetracycline. B. clausii, a facultative alkaliphilic could also tolerate acidic pH.amylase, alkaline protease, gelatinase, and mannanase were assayed for this organism. One of the most common anti-nutrient, limiting micronutrient bioavailability is phytate, inositol hexaphosphate. To assess the potential phytate degrading activity of the probiotic strain, we incubated a normal vegetarian lunch with B. clausii and measured soluble phosphate content. The soluble phosphate decreased after 1 hr of incubation. Binding efficiency to gelatin and fibronectin (host surface proteins) of isolates as well as B. clausii were determined. The probiotic organisms showed comparatively better binding than pathogenic strains to gelatin and fibronectin (fig 1). SDS-PAGE mediated zymography of gelatinase showed that B. clausii had very high gelatinase activity. But the MRS +ve isolates did not show any gelatinase activity measured at pH 7.4.
Overall, we isolated some local MRS selected strains from popular food and beverages of plant origin, which may potentially improve the nutrition condition in vegetarian diet, compete out the pathogenic infections and give an ecological and economically acceptable solution to the malnutrition problem in developing countries.