Role of Acinetobacter Bioemulsans in Petroleum Degradation

Rosenberg, Eugene; Barkay, Tamar; Navon-Venezia, Shiri; Ron, Eliora Z.

doi:10.1007/978-1-4615-4749-5_17

Cited by 12 publications

(4 citation statements)

References 24 publications

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“…Much less is known about how polymeric biosurfactants increase the apparent solubilities of hydrophobic compounds. Recently, it has been demonstrated that alasan increases the apparent solubilities of PAHs five‐ to 20‐fold and significantly increases their rate of biodegradation (Barkay et al ., 1999; Rosenberg et al ., 1999).…”

Section: Natural Roles Of Biosurfactantsmentioning

confidence: 99%

Natural roles of biosurfactants

Ron¹,

Rosenberg

2001

Environmental Microbiology

678

329

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Microorganisms produce a variety of surface‐active agents (or surfactants). These can be divided into low‐molecular‐weight molecules that lower surface and interfacial tensions efficiently and high‐molecular‐weight polymers that bind tightly to surfaces. These surfactants, produced by a wide variety of microorganisms, have very different chemical structures and surface properties. It is therefore reasonable to assume that different groups of biosurfactants have different natural roles in the growth of the producing microorganisms. Moreover, as their chemical structures and surface properties are so different, each emulsifier probably provides advantages in a particular ecological niche. Several bioemulsifiers have antibacterial or antifungal activities. Other bioemulsifiers enhance the growth of bacteria on hydrophobic water‐insoluble substrates by increasing their bioavailability, presumably by increasing their surface area, desorbing them from surfaces and increasing their apparent solubility. Bioemulsifiers also play an important role in regulating the attachment–detachment of microorganisms to and from surfaces. In addition, emulsifiers are involved in bacterial pathogenesis, quorum sensing and biofilm formation. Recent experiments indicate that a high‐molecular‐weight bioemulsifier that coats the bacterial surface can be transferred horizontally to other bacteria, thereby changing their surface properties and interactions with the environment.

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Section: Natural Roles Of Biosurfactantsmentioning

confidence: 99%

Natural roles of biosurfactants

Ron¹,

Rosenberg

2001

Environmental Microbiology

678

329

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“… Pseudomonas fluorescens Viscosin 71 Pseudomonas aeruginosa Rhamnolipids 72 Pseudomonas fluorescens Carbohydrate-lipid complex 39 Bacillus amyloliquefaciens, Surfactin/Iturin 73 Bacillus subtilis Subtilisin 74 Bacillus subtilis Lichenysin 75 Bacillus licheniformis K51, Bacillus subtilis Peptide lipids 76 Bacillus pumilus A1 Rhamnolipids 77 Bacillus sp. AB-2 Hydrocarbon-lipid-protein 78 Acinetobacter calcoaceticus Emulsan 79 Acinetobacter radioresistens Alasan 39 Acinetobacter calcoaceticus RAG1 Emulsan 80 Rhodococcus erythropolis Glycoprotein 81 Rhodococcus sp. 33 Uronic acids 82 Cyanobacteria Trehalose dicorynomycolate 83 Clostridium pasteurianum …”

Section: Introductionmentioning

confidence: 99%

Bioemulsifiers Derived from Microorganisms: Applications in the Drug and Food Industry

et al. 2018

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Emulsifiers are a large category of compounds considered as surface active agents or surfactants. An emulsifier acts by reducing the speed of chemical reactions, and enhancing its stability. Bioemulsifiers are known as surface active biomolecule materials, due to their unique features over chemical surfactants, such as non-toxicity, biodegradability, foaming, biocompatibility, efficiency at low concentrations, high selectivity in different pH, temperatures and salinities. Emulsifiers are found in various natural resources and are synthesized by Bacteria, Fungi and Yeast. Bioemulsifier’s molecular weight is higher than that of biosurfactants. Emulsion’s function is closely related to their chemical structure. Therefore, the aim of this paper was to study the various bioemulsifiers derived from microorganisms used in the drug and food industry. In this manuscript, we studied organisms with biosurfactant producing abilities. These inexpensive substrates could be used in environmental remediation and in the petroleum industry.

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“…During stationary phase, Acinetobacter radioresistens KA53 produces an extracellular bioemulsifier complex, referred to as alasan, that is composed of an anionic polysaccharide containing covalently bound alanine and four proteins ( Navon‐Venezia et al ., 1995 , 1998). Recently, it was demonstrated that alasan can stimulate the degradation of polyaromatic hydrocarbons (PAHs) by Sphingomonas paucimobilis EPA505 ( Barkay et al ., 1999 ; Rosenberg et al ., 1999 ). It was suggested that alasan stimulates the degradation of the hydrocarbons by increasing their apparent solubility.…”

Section: Introductionmentioning

confidence: 99%

Horizontal transfer of an exopolymer complex from one bacterial species to another

Osterreicher-Ravid

Ron

Rosenberg³

2000

Environmental Microbiology

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Alasan, the exocellular polymeric emulsifier produced by Acinetobacter radioresistens KA53 was shown to bind to the surface of Sphingomonas paucimobilis EPA505 and Acinetobacter calcoaceticus RAG-1. The presence of alasan on the surface of S. paucimobilis EPA505 and A. calcoaceticus RAG-1 caused a decrease in their cell-surface hydrophobicities. Binding was proportional to the concentration of recipient cells and input alasan. At the highest concentration of A. calcoaceticus RAG-1 (4 x 10(9) ml(-1)) and alasan (20 microg ml(-1)) tested, 75% of the alasan was cell bound. Alasan binding was measured by the loss of emulsifying activity and alasan protein and polysaccharide from the aqueous phase after incubation of alasan with the recipient cells. In addition, alasan was visualized on the surface of the recipient cells by staining with anti-alasan antibodies and rhodamine-labelled secondary antibodies. Moreover, when the alasan-producing A. radioresistens KA53 was grown together with A. calcoaceticus RAG-1, alasan was released from the producing strain and became bound to the recipient RAG-1 cells, as demonstrated by fluorescence microscopy. This horizontal transfer of exopolymers from one bacterial species to another has significant implications in natural microbial communities, coaggregation and biofilms.

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Role of Acinetobacter Bioemulsans in Petroleum Degradation

Cited by 12 publications

References 24 publications

Natural roles of biosurfactants

Natural roles of biosurfactants

Bioemulsifiers Derived from Microorganisms: Applications in the Drug and Food Industry

Horizontal transfer of an exopolymer complex from one bacterial species to another

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