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1	Author	Christoph Syldatk, Siegmund Lang, FritzW. Agner, Victor Wray, Ludger Witte	Requires cookie*
	Title	Chemical and Physical Characterization of Four Interfacial-Active Rhamnolipids from Pseudomonas spec. DSM 2874 Grown on /i-Alkanes
	Abstract	Four extracellular glycolip id s p rod u ced under g r o w th -lim itin g c o n d itio n s w ere iso la ted from the culture broth o f Pseudomonas spec. D SM 2874. A fter p u r ific a tio n by c o lu m n and th ick -la y er chrom atography they were id en tified as a n io n ic rh a m n o lip id s. 'H and '3C -N M R stu d ie s sh o w e d that two o f these, /? (/? (2 -0 -a -L -rh a m n o p y ra n o sy lo x y)d eca n o y l)d eca n o ic a cid and /?(/?(2-0-a-L -rh a m n o p y ran osyl-x-L -rh am n op yran osyloxy)d ecan oyloxy)d ecan oic acid , w ere id en tica l w ith c o m pounds described previously, w h ile the other m ore h y d r o p h ilic c o m p o u n d s, /? (2 -0 -a -L -r h a m n o -p yranosyloxy)decanoic acid and /? (2 -0 -a -L -r h a m n o p y ra n o sy l-ix -L -rh a m n o p y ra n o sy lo x y)d e ca n o ic acid, were new com pounds. Surface and interfacial activity o f the organic crude extract and o f the purified com ponents were determined in different aqueous solutions. The pH -dependence o f surface and interfacial properties o f the two previously described rham nolipids (4, 20. 23) were exam ined in Teorell-Stenhagen-buffer (supplemented with 10% N aC l) at pH 3.0 and pH 9.0. All rham nolipids reduced the surface-tension from 72 to about 30 m N / m and the interfacial-tension from 42 to about 1 m N /m . The critical m icelle concentrations were o f the order o f 5 to 200 mg/1 depending on the structure o f the molecule.
	Reference	Z. Naturforsch. 40c, 51—60 (1985); received August 20 1984
	Published	1985
	Keywords	Pseudomonas, Interfacial-Active, Rham nolipids, «-Alkanes, Structure-Eludication
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	TEI-XML for	default:Reihe_C/40/ZNC-1985-40c-0051.pdf
	Identifier	ZNC-1985-40c-0051
	Volume	40

2	Author	C. Syldatk, S. Lang, U. Matulovic, F. W. Agner	Requires cookie*
	Title	Production of Four Interfacial Active Rhamnolipids from /i-Alkanes or Glycerol by Resting Cells of Pseudomonas species DSM 2874
	Abstract	In a simple phosphate buffer or a sodium chloride solution resting cells o f Pseudom onas spec. DSM 2874 produced up to 15 g/1 o f different rham nolipids. The rham nolipid com position o f the organic crude extract depended on the temperature during the cultivation and on the C-source. The optimal sodium chloride concentration for rham nolipid form ation was about 100 mM/1 and the optimal phosphate buffer concentration about 65 mM/1. The optim al pH -value for the production o f rhamnolipids from «-alkanes or glycerol was in the range pH 6.0 -7 . 2 . W hile rhamnolipid formation with glycerol as the sole C-source show ed a w ide optim um ranging from 27 ° up to 37 °C, production o f rhamnolipids from «-alkanes had a sharp optim um at 37 °C. The addition o f multivalent cations, different N -sources and E D T A caused an inhibition o f rhamnolipid formation, while the «-alkane concentration had no influence. Specific rham nolipid formation decreased with increasing cell concentration. Various C-sources were suitable for the formation o f rhamnolipids by resting cells o f Pseudom onas spec. D S M 2874. Yields, which were comparable to those obtained on «-alkanes or glycerol, were found for stearic acid, fatty alcohols and vegetable oils. A study o f the time course o f glycolipid production o f resting cells was carried out in a 20 1-biorcactor with an intensor system and with «-tetradecane as the sole C-source.
	Reference	Z. Naturforsch. 40c, 61—67 (1985); received August 2 0 /0 c to b e r 23 1984
	Published	1985
	Keywords	Pseudomonas, Interfacial-Active, Rham nolipids, «-Alkanes, Resting Cells
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	TEI-XML for	default:Reihe_C/40/ZNC-1985-40c-0061.pdf
	Identifier	ZNC-1985-40c-0061
	Volume	40