Lactic acid bacteria (LAB) are among the most important group of bacteria, with a critical role in food, pharmaceutical and medical industry. The fast-growing characteristics of LAB strains, their metabolic activity associated with production of many beneficial compounds and most of all, their GRAS status (Generally Recognized As Safe) recommends them as starter cultures for food biotechnology processes. During last decades, LAB strains have also an extensive prophylactic or therapeutic use as probiotics. Due to the fact that there are current limitations in the use of standard MRS media (de Man Rogosa Sharpe), which is selective especially for lactobacilli and enterococci, the aim of the present study was to optimize the growth medium composition for isolating a wide range of LAB strains with biotechnological potential and to improve the biomass accumulation. For this purpose, it has been evaluated the growth of Lactobacillus (L.) rhamnosus ATCC� 9595�, Streptococcus (S.) salivarius subsp. thermophilus ATCC� 19258�, Pediococcus (P.) acidilactici ATCC� 8042�, Lactococcus (L.) lactis 28 and Enterococcus (E.) faecium FFb CMGB L-18 on MRS broth with various carbon sources (glucose, lactose, galactose, maltose, mannose, ribose, arabinose, sucrose, fructose). The results of the study showed that there are interesting differences in the requirements of each analyzed species. The optimization of standard medium composition will be very useful for growth studies as well as metabolic flux studies.
During last decades, there is a growing interest for characterizing new microbial strains isolated from various sources (plants, soil and natural fermentative processes), in order to enhance industrial productivity. The aim of the present study was to assess the profile of cell growth parameters and biomass accumulation of 15 newly isolated yeast and lactic acid bacteria (LAB) strains from Romanian spontaneous fermented dairy products under different environmental stress conditions (chemical and physical). On this purpose, the yeast and LAB strains were characterized and identified using MALDI-TOF MS and selected for their biotechnological potential. Cell growth was evaluated in presence of extreme pH values, temperatures and different NaCl concentrations. All strains included in this study grew well under their optimal conditions; some of them preferred extreme parameters: acid / very alkaline pH, high temperatures or NaCl concentration The characterization of microbiota from Romanian spontaneous fermented dairy products might represent a great opportunity for the development of dairy industry using native microorganisms, preserving thus the Romanian biodiversity and cultural heritage.
Lactic acid bacteria (LAB) are an important part of the microbiota of fermented food and beverages from all over the world, their contribution to preservation and safety of food to which they also confer specific attractive textures and aromas being essential. Certain selected strains were characterized in terms of their probiotic activity, positively reflecting on consumers' health. LAB can also be regarded as sources of functional compounds such as vitamins, enzymes a. o., with applications in the food and in the pharmaceutical industry. The screening of LAB from local or traditional fermented foods for their biotechnological potential continues to be a very promising direction of research. The aim of the present study was the characterization of newly isolated LAB strains from various spontaneously fermented foods and beverages locally produced in Romania and the evaluation of their biotechnological characteristics. A total of 130 LAB strains were examined for their acidification potential, for the production of organic acids, exopolysaccharides (EPS) and diacetyl, for their citrate fermentation capacity, and for their proteolytic and lipolytic activity. A series of strains that were considered to hold potential for further applications could be selected in view of further, more detailed studies.
Keywords
Lactic acid bacteria screening, local fermented foods and beveragesTo cite this article: PETRUŢ ȘM, SÂRBU I, CORBU VM, PELINESCU D, IFTIME I, DIMOV TV. Screening of lactic acid bacteria from spontaneously fermented products of Romania.
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