Synthesis and Recovery of N-Sulfo Heparosan From Fermentation Broth

Heparosan, a glycosaminoglycan (GAG) derived from bacterial capsular polysaccharide (CPS), shares a similar backbone with both clinically utilized heparin and heparan sulfate (HS). This facilitates its transformation into heparin/HS via chemoenzymatic strategies. Currently, the purification process of heparosan, followed by N-deacetylation and N-sulfation, requires executing several complex steps prone to the unintended loss of polysaccharides and environmental risks. In this study, heparosan extracted from fermentation broth underwent immediate N-deacetylation and N-sulfation before DEAE chromatography purification. The results showed that the recovery of N-deacetylated heparosan increased from less than 40% to 93.6% with negligible contaminants. After sulfation, the overall recovery yield of N-sulfo heparosan was 76.0%. The number average molecular weight (M_n) and weight average molecular weight (M_W) of N-sulfo heparosan were ascertained to be 5.2 and 10.7, respectively, with a polydispersity index (PDI) value of 2.1. The assessment of elemental composition revealed that the efficiency of N-sulfation was 84%, which aligns with that of commercial heparin. The strategy delineated in this investigation avoids the substantial loss of N-deacetylated polysaccharides resulting from the complex procedures. Furthermore, the study avoids using harmful organic solvents in preparing heparosan, thereby promoting the in vitro green synthesis of heparin-like polysaccharides and analogous pharmaceutical compounds.