Optimization of production of Microbial Exopolysaccharides (EPS) with essential oils from two medicinal plants

Abstract

Objective: The aim of our study is to evaluate the effect of essential oils of two medicinal plants: Atriplex halimus and Haloxylon scoparium on the production of EPS by four probiotic strains. Methodology and results: Exopolysaccharides (EPSs) of lactic acid bacteria have potential for development and exploitation as food additives and functional food ingredients with both health and economic benefits. In this study, EPS production was carried at sucrose broth with different parameters (inoculum size, temperature, pH, incubation period, sucrose concentration, oxygen tension). In addition, under an optimized condition the effect of essential oils of two medicinal plants: Atriplex halimus (A.H.) and Haloxylon scoparium (H.S.) was evaluated on EPS production by four strains (Leuconostoc sp., Lactobacillus sp. and two strains Pediococcus sp.). The production kinetics and exopolysaccharide yields were strongly dependent on the fermentation conditions. Physical factors such as temperature, pH and oxygen tension had a primordial importance. Conditions leading to higher levels of EPS production depends on strains and adequate concentrations of sucrose (50 g/l), pH (6,5 for Leuconostoc sp. and Pediococcus sp., 2; 4,5 for Lactobacillus sp. and 5 for Pediococcus sp. 1, incubation period (18 hours), temperature (37°C from Leuconostoc sp. and Pediococcus sp. 1, 30°C from Lactobacillus sp., 50°C from Pediococcus sp. 2) and medium of production (broth sucrose). The introduction of essential oils (150 µl) of tested plants improved the production of EPS from 7.9 -9.73 mg/ml of all strains to 15.2 -16.28 with essential oils of Atriplex halimus and 11.6-13.2 mg/ml with essential oil of Haloxylon scoparium. Results showed an important stimulation of the exopolysaccharides production by essential oils of two plants (A.H. and H.S.) Conclusion and Application of results: Our strains have shown their ability to produce maximum levels of EPS in the case of the addition of essential oils extracted from medicinal plants. These substances can be used as additives in the food industry to increase the productivity of the lactic strains of EPS as well as in the pharmaceutical field to prepare some medications.

Lactobacillus exopolysaccharide: An Untapped Biopolymer

“…We strongly believe that the ability of the scientific community to solve this problem of poor yield rest on intensified scientific research. However, several types of research have been conducted and some are ongoing towards finding ways of improving the yield of this very important polymer [57][58][59][60].…”

Screening for efficient nitrogen sources for overproduction of the biomass of the functionally probiotic L. plantarum strain RPR42 in a cane molasses-based medium

“…Many studies have tried medium optimization for increased biomass production of lactobacilli (Horn et al 2005;Krzywonos and Eberhard 2011;Hwang et al 2012;Yoo et al 2018), however, the medium optimization for lactobacilli have mainly aimed the production of bacteriocins (Barman et al 2018), exopolysaccharides (Benhadria et al 2017) and lactic acid (Srivastava et al 2015).…”

Phenotypic and Genotypic Characterization of Exopolysaccharide Producing Bacteria Isolated from Fermented Fruits, Vegetables and Dairy Products

“…LAB is generally recognized as safe (GRAS) in which no reports of any illness or toxicity recorded or any harmful compounds produced by them 1 . Recently, lactic acid bacteria (LAB) stirred up a sensation for their ability to produce many valuable products in particular extracellular polysaccharides (EPS) 2 . EPS from LAB have acknowledge dincreasing consideration because of their budding importance in various fields 3,4,5 .…”

“…Also, EPS is characterized depending on the nature of mucous colonies as "ropy" colonies that produce viscous strands when pulled with an inoculating loop or resistance of liquid EPS to flow through serological pipettes and produce long filament and go down from the pipette tip 11 . While the"nonropy"colonies that are slime or mucoid colonies but not able to form a long filament when extended with an inoculation loop 2,12 .…”