Low-Temperature Biosurfactants from Polar Microbes.

Benjamin Trudgeon,Markus Dieser,Christine M Foreman,Narayanaganesh Balasubramanian,Mitch Messmer

doi:10.3390/microorganisms8081183

Benjamin Trudgeon, Markus Dieser + Show 3 more

Open Access

https://doi.org/10.3390/microorganisms8081183

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Journal: Microorganisms	Publication Date: Aug 3, 2020
Citations: 15	License type: CC BY 4.0

Affiliation: Montana State University

Abstract

Surfactants, both synthetic and natural, are used in a wide range of industrial applications, including the degradation of petroleum hydrocarbons. Organisms from extreme environments are well-adapted to the harsh conditions and represent an exciting avenue of discovery of naturally occurring biosurfactants, yet microorganisms from cold environments have been largely overlooked for their biotechnological potential as biosurfactant producers. In this study, four cold-adapted bacterial isolates from Antarctica are investigated for their ability to produce biosurfactants. Here we report on the physical properties and chemical structure of biosurfactants from the genera Janthinobacterium, Psychrobacter, and Serratia. These organisms were able to grow on diesel, motor oil, and crude oil at 4 °C. Putative identification showed the presence of sophorolipids and rhamnolipids. Emulsion index test (E24) activity ranged from 36.4–66.7%. Oil displacement tests were comparable to 0.1–1.0% sodium dodecyl sulfate (SDS) solutions. Data presented herein are the first report of organisms of the genus Janthinobacterium to produce biosurfactants and their metabolic capabilities to degrade diverse petroleum hydrocarbons. The organisms’ ability to produce biosurfactants and grow on different hydrocarbons as their sole carbon and energy source at low temperatures (4 °C) makes them suitable candidates for the exploration of hydrocarbon bioremediation in low-temperature environments.

Highlights

Surfactants, known as surface-active agents, are commonly used in many different industries, including paints, textiles, detergents, health, and personal care products, as well as mineral and petroleum processing [1,2,3,4]
Putative identification of rhamnolipids showed a pronounced peak for di-rhamnolipid C12–C12 for all four bacterial isolates, while other rhamnolipid peaks could have been masked by the noise of the measurement
The predominance of putatively identified di-rhamnolipid C10–C10 and di-rhamnolipid C12–C12 implies that the physicochemical properties of the biosurfactants produced by the four Antarctic isolates could be up to ~8 and 45 times more effective when compared to mono-rhamnolipids with C10 fatty acids or rhamnolipid mixtures with high proportions of congeners containing unsaturated fatty acids, respectively [59]

Summary

Introduction

Surfactants, known as surface-active agents, are commonly used in many different industries, including paints, textiles, detergents, health, and personal care products, as well as mineral and petroleum processing [1,2,3,4]. Highly effective in many industrial and remediation applications, synthetic surfactants tend to be toxic and can pose environmental hazards and biocidal activity [5] They have low biodegradability and can solubilize hydrophobic xenobiotics, affecting drinking water quality and wastewater treatment [6,7]. Some of the most common types of biosurfactants are glycolipids, rhamnolipids, sophorolipids, trehalolipids, lipoproteins and lipopeptides, fatty acids, phospholipids, and polymeric structures, such as emulsan and liposan [11,13,17] Akin to their synthetic counterparts, these different types of biosurfactants have broad commercial application, as they offer safer, more effective alternatives [8,17,18,19,20,21,22,23,24,25,26]. Biosurfactants may play a role as osmolytes [28], and glycolipid biosurfactants isolated from an Antarctic yeast have shown ice recrystallisation inhibitory activity [29]

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