A SOLID PHASE EXTRACTION TECHNIQUE FOR HPLC ANALYSIS OF SHORT CHAIN FATTY ACID FLUXES DURING MICROBIAL DEGRADATION OF PLANT POLYMERS

The purpose of this work was to develop a solid phase extraction (SPE) technique to remove interfering compounds that resulted in non-specific, long retention time peaks in HPLC chromatographs. The SPE technique shortened the HPLC run times from 140 to 70 min for analysis of short chain fatty acids (SCFAs). Samples contained partially degraded cellulose, hemicellulose, pectin, starch, and chitin following incubation with a microbial consortium. The SPE procedure was based on retention of large hydrophobic compounds but the results also indicated entrapment of <0.2 µm particles of polymer residues. Reproducibility varied between individual SCFAs but the standard deviations remained below 10%. HPLC samples that contain colloids and solutes stemming from the biodegradation of natural, insoluble polymers can be treated with this SPE protocol. Thus the technique is useful for examining metabolite fluxes in microbial cultures with suspended solids and in solid phase fermentation.