Production of four interfacial active rhamnolipids from ɳ-alkanes or glycerol by resting cells of pseudomonas species DSM 2874

Abstract

In a simple phosphate buffer or a sodium chloride solution resting cells of Pseudomonas spec.DSM 2874 produced up to 15 g/1 of different rhamnolipids. The rhamnolipid composition of the organic crude extract depended on the temperature during the cultivation and on the C-source.The optimal sodium chloride concentration for rhamnolipid formation wasabout 100 mM/1 and the optimal phosphate buffer concentration about 65 mM/1.The optim al pH-value for the production ofrhamnolipids from «-alkanes or glycerol was in the range pH 6.0 - 7.2.While rhamnolipid formation with glycerol as the sole C-source showed a wide optimum ranging from 27° up to37 °C, production of rhamnolipids from «-alkanes had a sharp optim um at 37 °C. The addition of multivalent cations, different N-sources and EDTA caused an inhibition of rhamnolipid formation, while the «-alkane concentration had no influenc.Specific rhamnolipid formation decreased with increasing cell concentration. Various C-sources were suitable for the formation of rhamnolipids by resting cells of Pseudomonasspec. DSM 2874.Yields, which were comparable to those obtained on ɴ-alkanes or glycerolwere found for stearic acid, fatty alcohols and vegetable oils A study of the time course of glycolipid production \of resting cells was carried out in a 201-biorcactor with an intensor system and with ɴ-tetradecane as the sole C-source. © 1985, Walter de Gruyter. All rights reserved.