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Growth and heavy metals uptake by Vicia faba in mining soil and tolerance of its symbiotic rhizobacteria

El Alaoui Abdelkhalek, Bechtaoui Noura, Benidire Loubna, El Gharmali Abdelhay, Achouak Wafa, Daoui Khalid, Imziln Boujamaa, Oufdou Khalid

Environment Protection Engineering

2019

Vol. 45, nr 1

83--96

Faba bean plants in the 1/8 mixture with soil had the ability to accumulate Pb, Zn and Cu. 95% of the absorbed Pb were in the roots, and Cu and Zn were found in the shoots by 35% and 45%, respectively. There was a decrease in the root hairs and the number of cell layers of the root cortex alongside epidermis lesions. From the 50 tested rhizobacterial strains, 20 were able to grow at 150 mg/dm3 of Pb, 6 were resistant to 150 mg/dm3 of Zn and 8 resisted to 20 mg/dm3 of Cu. Best four strains had adsorption potentials and the biosorption was higher for Cu. These strains were capable of producing auxin and exopolysaccharides. The most tolerant strains (FD1 and FD2) isolated near the mining site produced siderophores and high amounts of exopolysaccharides. The use of such strains and V. faba could be of important biotechnological value in decreasing heavy metal pollution of mining soils.

Egzopolisacharydy bakteryjne : budowa i funkcje

Samaszko-Fiertek J., Kuźma M., Dmochowska B., Ślusarz R., Madaj J.

Wiadomości Chemiczne

2016

[Z] 70, 7-8

473--496

Exopolysaccharides fulfil protective functions and allow bacteria live in the communities, single or mixed, by facilitating adhesion to surfaces and to each other. Microbes prefer to exist in the form of a biofilm. The term biofilm was introduced in 1978 and is the group of microorganisms surrounded by extracellular, highly hydrated mucus, which allows adhesion on various surfaces and adhesion of cells to each other [1]. The extracellular slime owes its character mainly due to the presence of exopolysaccharides. Bacteria living in biofilms, have a high resistance to external factors, such as changes in temperature, pH, humidity, oxygenation, presence of bacteriocins, antibodies or antibiotics. They may be up to 1,000 times more resistant to antibiotics than planktonic forms. They can be synthesized inside and outside bacteria cell. The structure of the bacterial exopolysaccharide is very diverse, but very often, due to the presence of uronic acid residues, or non-sugar organic acids as pyruvic acid, succinic acid, as well as residues of inorganic acids such as phosphoric acid or sulfuric acid, they are negatively charged particles. In addition, a characteristic of most of the exopolysaccharides (EPS) is their enormous molecular mass of up to several million g/mol [11]. Thanks to its rheological properties, ease of isolation, and often biodegradable antioxidant activity extracellular polysaccharides are increasingly used in industry as a gelling agents, hardening and thickening agents, emulsifiers, food coatings and pharmaceutical products. In addition, they can be used as bandages, anti-cancer agents, cholesterol-lowering, antiulcer or immunomodulators [20–27]. This article discusses in details the selected exopolysaccharides such as xanthan, gellan, exopolysaccharides of lactic acid bacteria, dextran, bacterial cellulose, alginic acid, hyaluronic acid, mannans.

Zastosowanie egzopolisacharydów produkowanych przez bakterie kwasu mlekowego

Markowicz C., Schmidt M. T.

Przemysł Spożywczy

2015

T. 69, nr 11

18--20

Polisacharydy są substancjami mającymi liczne zastosowania w przemyśle spożywczym. Wpływają na poprawienie cech sensorycznych i stabilności konsystencji produktów spożywczych, a także są czynnikiem teksturotwórczym. Są związkami naturalnymi, również syntetyzowanymi przez bakterie kwasu mlekowego. Substancje te, dostarczane do organizmu wraz z produktami spożywczymi, często wywierają korzystny wpływ na zdrowie [20]. Mogą stanowić bezpieczną alternatywę dla niektórych dodatków teksturotwórczych stosowanych w przemyśle spożywczym. W wielu produktach fermentowanych, takich jak jogurty czy kefiry, egzopolisacharydy bakterii kwasu mlekowego występują naturalnie. Dopiero odkrycie i scharakteryzowanie tych związków w połowie XIX w. umożliwiło ich świadome wykorzystanie w celu poprawy jakości żywności.

Polysaccharides are substances which have numerous applications in the food industry. Their presence in food can improve sensory properties, texture and stability of products. They are natural compounds, synthesized, among others, by lactic acid bacteria. Bacterial exopolysaccharides ingested with food often have a beneficial effect on human health [20]. They can therefore provide a safe alternative for many additives used in the food industry. In many fermented products, such as yoghurt and kefir, exopolysaccharides produced by lactic acid bacteria may occur naturally. The discovery and characterization of these compounds in the mid-nineteenth century resulted in new possibilities of their use in order to improve the quality of food.