Chemical characterization of rhamnolipids produced by Pseudomonas aeruginosa AT10 from residue soybean oil by HPLC-EM

Abstract

The hybridization liquid chromatography-mass spectrometry is applied for the characterization of hormones,
drugs, rhamnolipids and other compounds. The rhamnolipids are microbial tensoactives produced by Pseudomonas aeruginosa
with different substrates. The soybean oil waste contains linoleic (48.4 %) and oleic (21.1 %) acids fundamentally. In
this work was determined the chemical and structural composition of the rhamnolipids of the Pseudomonas aeruginosa
AT10 with soybean oil waste utilizing instrumental hybridization High Pressure Liquid Chromatography-Mass Spectrometry.
The structural characterization of the rhamnolipids evidenced the presence of eight peaks that correspond to
the dirhamnolipids (51.5 %) R2C10C10; R2C10C12:1; R2C10C12 and the monorhamnolipids (48.5 %) R1C10C10; R1C10C12:1; R1C10C12;
R1C12:2; R1C8:2. The negative electrospray visualized that the most abundant fragmentation in the monorhamnolipids
was the corresponding to the [M–H]- 169, in the homologous RhaC10C10, RhaC10C12 and RhaC10C12:1, that corresponding
to the pseudomoleculars ions [M–H]- 503, 531 and 529 respectively. For the dirhamnolipids RhaRhaC10C10, RhaRhaC10C12
and RhaRhaC10C12:1, it was observed that the pseudomolecular ion [M-H]- 649, 675 and 677, respectively, was the most
abundant peak The fragmentation of the ester link permitted to separate monorhamnolipids and dirhamnolipids among
themselves and identified him at the specific isomer in the four equal isomers RhaC10C12/RhaC12C10, RhaC10C12:1/RhaC12:1C10,
RhaRhaC10C12/RhaRhaC12C10, RhaRhaC10C12:1/RhaRhaC12:1C10. The hybridization HPLC/MS permitted to evaluate also the
accumulation out of every counterpart during the time of cultivation. In the first 24 h only were detected the rhamnolipids
RhaRhaC10C10 and RhaC10C10.