Dear Rakesh,

The attached publications cover the answer to your question.

STRUCTURE OF SURFACTIN A SYNTHETASE C (SRFA-C), A NONRIBOSOMAL PEPTIDE SYNTHETASE TERMINATION MODULE

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X-RAY DIFFRACTION Experimental Data & Validation

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Crystallization

Crystalization Experiments

pH

7.5

Details

0.1 M MGCL2, 0.05 M HEPES (PH 7.5), 15 % (W/V) PEG 2000

http://www.rcsb.org/pdb/explore/materialsAndMethods.do?structureId=2vsq

1-Journal of Membrane Science 325 (2008) 599–604

Extraction of surfactin from fermentation broth with n-hexane in microporous

PVDF hollow fibers: Significance of membrane adsorption

Huei-Li Chena, Ruey-Shin Juanga,b,∗

abstract

In order to avoid foaming behavior and the formation of stable emulsions in traditional extraction, nondispersive extraction of surfactin from the fermentation broth of Bacillus subtilis ATCC 21332 culture with n-hexane was studied in microporous polyvinylidene fluoride (PVDF, pore size 0.2 m) hollow fiber module.

In this work, the broth was pretreated by acid precipitation and the precipitate was then dissolved in NaOH solution, and the treated broth was passed through the lumen side of the module and n-hexane was flowed across the shell side. Experiments were performed at a fixed pH of 8.0 and a flow rate of both

phases of 2.5 mL min−1 but at different surfactin concentrations (300–3000 mg L−1). Under the conditions studied, it was shown that surfactin was adsorbed onto the surface of the fibers, instead of being extracted by n-hexane and transported through the pores of the fibers into bulk n-hexane phase. The adsorption

capacity was determined and the adsorption dynamics was analyzed. The purity of surfactin desorbed from the fibers with ethanol was found to be higher than that obtained after solvent extraction with n-hexane.

2-XXIII ARS SEPARATORIA – Toruń, Poland 2008 65

LIQUID MEMBRANE EXTRACTION OF LIPOPEPTIDES

Krasimir DIMITROV1,2), Frederique GANCEL1), Ludovic

MONTASTRUC1), Pascal DHULSTER1), Iordan NIKOV1)

1) Laboratoire ProBioGEM EA 1026, Polytech’Lille, USTL, Lille, France

2) Institute of Chemical Engineering, Bulgarian Academy of Sciences, Sofia,

Bulgaria

Surfactants of biological origin are of increasing interest for many

industries due to their chemical diversity, multifunctional characteristics

and low toxicity in comparison to synthetic, petrochemical-derived

surfactants. A lipopeptide surfactin is one of the most powerful

biosurfactants. Microbiological productivities, properties and applications

of lipopeptides, including surfactin, have been extensively studied [1-3].

However, there is a lack of information about their separation, purification

and concentration. In fact biosurfactants are not yet widely available

because of their high production costs, which results primarily from low

strain productivities and high recovery expenses.

The selective recovery and concentration of such lipopeptides from

fermentation broth largely determines the production cost. The low

concentrations and the amphiphilic character of these compounds pose

serious limitations to their efficient recovery. Thus, development of

efficient separation technologies is of growing interest. The commonly

used methods for biosurfactants recovery are foam separation, acid

precipitation, and solvent extraction [4]. The latter technique provides

higher biosurfactant purity comparing to the other two methods [5]. The

main inconvenient of solvent extraction is the problem with regeneration of

the loaded solvent, and therefore the use of important quantities of solvent.

In addition, the most efficient and generally used for lipopeptides recovery

solvents, such as chloroform, methanol, and acetone, are known to be toxic

and harmful to the environment and human health.

3- BMC Microbiol. 2012; 12: 252.

Published online 2012 Nov 7. doi:  10.1186/1471-2180-12-252

PMCID: PMC3577442

Purification and characterization of a surfactin-like molecule produced byBacillus sp. H2O-1 and its antagonistic effect against sulfate reducing bacteria

Elisa Korenblum,1 Livia Vieira de Araujo,2 Carolina Reis Guimarães,2 Lauro M de Souza,3 Guilherme Sassaki,3Fernanda Abreu,1 Márcia Nitschke,4 Ulysses Lins,1 Denise Maria Guimarães Freire,2 Eliana Barreto-Bergter,1 and Lucy Seldin 1,5

Author information ► Article notes ► Copyright and License information ►

This article has been cited by other articles in PMC.

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Abstract

Background

Bacillus sp. H2O-1, isolated from the connate water of a Brazilian reservoir, produces an antimicrobial substance (denoted as AMS H2O-1) that is active against sulfate reducing bacteria, which are the major bacterial group responsible for biogenic souring and biocorrosion in petroleum reservoirs. Thus, the use of AMS H2O-1 for sulfate reducing bacteria control in the petroleum industry is a promising alternative to chemical biocides. However, prior to the large-scale production of AMS H2O-1 for industrial applications, its chemical structure must be elucidated. This study also analyzed the changes in the wetting properties of different surfaces conditioned with AMS H2O-1 and demonstrated the effect of AMS H2O-1 on sulfate reducing bacteria cells.

Results

A lipopeptide mixture from AMS H2O-1 was partially purified on a silica gel column and identified via mass spectrometry (ESI-MS). It comprises four major components that range in size from 1007 to 1049 Da. The lipid moiety contains linear and branched β-hydroxy fatty acids that range in length from C13 to C16. The peptide moiety contains seven amino acids identified as Glu-Leu-Leu-Val-Asp-Leu-Leu.

Transmission electron microscopy revealed cell membrane alteration of sulfate reducing bacteria after AMS H2O-1 treatment at the minimum inhibitory concentration (5 μg/ml). Cytoplasmic electron dense inclusions were observed in treated cells but not in untreated cells. AMS H2O-1 enhanced the osmosis of sulfate reducing bacteria cells and caused the leakage of the intracellular contents. In addition, contact angle measurements indicated that different surfaces conditioned by AMS H2O-1 were less hydrophobic and more electron-donor than untreated surfaces.

Conclusion

AMS H2O-1 is a mixture of four surfactin-like homologues, and its biocidal activity and surfactant properties suggest that this compound may be a good candidate for sulfate reducing bacteria control. Thus, it is a potential alternative to the chemical biocides or surface coating agents currently used to prevent SRB growth in petroleum industries.

Keywords: Antimicrobial substance, Surfactin-like lipopeptide, Bacillus sp., Sulfate reducing bacteria

Hoping this will be helpful,

Rafik

http://www.sciencedirect.com/science/article/pii/S0376738808007771

http://www.sciencedirect.com/science/article/pii/S1369703X11003287

http://core.ac.uk/download/files/437/12039706.pdf

Thank you very much Rafik Karaman and Kavuthodi Bijesh for your kind support.

these are very useful in my research.