An Acidic Exopolysaccharide from Haloarcula hispanica ATCC33960 and Two Genes Responsible for Its Synthesis

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Abstract

A 1.1 × 10 6 Da acidic exopolysaccharide (EPS) was purified from an extremely halophilic archaeon Haloarcula hispanica ATCC33960 with a production of 30 mg L −1 when grown in AS-168 medium, which mainly composed of mannose and galactose with a small amount of glucose in a molar ratio of 55.9 : 43.2 : 0.9. Two glycosyltransferase genes ( HAH_1662 and HAH_1667 ) were identified to be responsible for synthesis of the acidic EPS. Deletion of either HAH_1662 or HAH_1667 led to loss of the acidic EPS. The mutants displayed a different cell surface morphology, retarded growth in low salty environment, an increased adhesion, and swimming ability. Our results suggest that biosynthesis of the acidic EPS might act as an adaptable mechanism to protect the cells against harsh environments.

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Advances in bacterial exopolysaccharides: from production to biotechnological applications.

Filomena Freitas, Vitor D. Alves, Mitermayer G. Reis (2011)

A vast number of bacterial extracellular polysaccharides (EPSs) have been reported over recent decades, and their composition, structure, biosynthesis and functional properties have been extensively studied. Despite the great diversity of molecular structures already described for bacterial EPSs, only a few have been industrially developed. The main constraints to full commercialization are their production costs, mostly related to substrate cost and downstream processing. In this article, we review EPS biosynthetic and fermentative processes, along with current downstream strategies. Limitations and constraints of bacterial EPS development are stressed and correlation of bacterial EPS properties with polymer applications is emphasized. Copyright © 2011 Elsevier Ltd. All rights reserved.

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Microbial exopolysaccharides: Main examples of synthesis, excretion, genetics and extraction

F. Donot, A Fontana, J.C. Baccou … (2012)

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Biosurfactants, bioemulsifiers and exopolysaccharides from marine microorganisms.

Surekha Satpute, Ibrahim M. Banat, Prashant K. Dhakephalkar … (2010)

Marine biosphere offers wealthy flora and fauna, which represents a vast natural resource of imperative functional commercial grade products. Among the various bioactive compounds, biosurfactant (BS)/bioemulsifiers (BE) are attracting major interest and attention due to their structural and functional diversity. The versatile properties of surface active molecules find numerous applications in various industries. Marine microorganisms such as Acinetobacter, Arthrobacter, Pseudomonas, Halomonas, Myroides, Corynebacteria, Bacillus, Alteromonas sp. have been studied for production of BS/BE and exopolysaccharides (EPS). Due to the enormity of marine biosphere, most of the marine microbial world remains unexplored. The discovery of potent BS/BE producing marine microorganism would enhance the use of environmental biodegradable surface active molecule and hopefully reduce total dependence or number of new application oriented towards the chemical synthetic surfactant industry. Our present review gives comprehensive information on BS/BE which has been reported to be produced by marine microorganisms and their possible potential future applications.