Biosurfactant, especially the microbially derived surfactant, is essential
for the recovery and production of petroleum from oil reservoirs. The spicu
lisporic acid (S-acid) can be easily obtained from a fungus, Penicillium sp
iculisporum by aerobic cultivation. It was especially found that a great nu
mber of n-alkylamine salts can be formed with the S-acid. The chain of the
alkylamine moiety can be adjusted for a desirable interfacial tension. The
use of the hydrophilic-hydrophobic balance (HLB) is illustrated. It is poss
ible to develop a suitable in-situ surfactant for a specific application in
any porous medium by an above-the-ground fermentation with the appropriate
reaction with an n-alkylamine. Because of the huge quantities of n-alkylam
ines available, the production of this type of surfactant should be cost-ef
ficient. (C) 1998 Elsevier Science B.V. All rights reserved.