the above described limiting features the temperature of the culture suspension can also be raised or lowered to 15 u00b0 c at the end of the logarithmic growth period for example by simultaneous limitation of the nitrogen according to this variant of the process of the invention over 7 800 mg of trehalose lipids are obtained per 1 of culture suspension a further increase in the yield of trehalose lipids can be obtained according to the inventron by adding a bacteriostatic agent e g at least 0 01 to 0 02 g l of d n n 39 bis 1 hydroxymethylpropyl ethylenediamine dihydrochloride ethambutol to the nutrient salt solution after its sterilization with simultaneous nitrogen limitation and temperature lowering during the growth period the yield of trehalose lipids rises to over 10 000 mg l of culture suspension according to this variant of the process of the invention the isolation of the trehalose lipids obtained according to the different embodiments of the process according to the invention is accomplished by known methods thus the culture solution can be exhaustively extracted with a mixture of methylene chloride methanol in the volume ratio of 2 1 the obtained extract is then concentrated under vacuum to yield a crude extract from which the unreacted hydrocarbons are separated these can then be reused in the process of the invention the residue comprises a mixture of trehalose lipids which contains depending upon the particular embodiment up to 10 to 40 wt of non ionic and up to 60 to 90 wt of anionic trehalose lipids comprising 0 75 to 10 5 g l of.