Exploitation of Vibrio alginolyticus Mo245 as a dual producer of a glycosaminoglycan and poly(3-hydroxybutyrate) from glycerol.

In the present work, the marine bacterium Vibrio alginolyticus Mo245 demonstrated the ability to secrete an extracellular polysaccharide (EPS) concomitant with the intracellular accumulation of a polyhydroxyalkanoate (PHA). Upon cultivation in glycerol as the sole carbon source, V. alginolyticus Mo245 co-produced a glycosaminoglycan (GAG), named EPS-Mo245, and the homopolymer poly(3-hydroxybutyrate) (P3HB), attaining maximum concentrations of 1.29±0.01 g/L and 1.78±0.00 g/L, respectively, within a 24 h cultivation. EPS-Mo245 was a hyaluronic acid (HA)-like GAG, composed of glucuronic acid (40.5±2.2 mol%), galactosamine (29.8±0.2 mol%), and glucosamine (21.1±0.6 mol%). It presented an average molecular weight (Mw) of 1945±67 kDa, with a polydispersity index (PDI) of 1.29±0.02, and a thermal degradation temperature of 235 °C. The produced P3HB had a Mw of 110±0.00 KDa and a PDI of 1.70±0.08, characterized by melting and thermal degradation temperatures of 175 °C and 293 °C, respectively, within the range of values reported for P3HB. These findings demonstrate V. alginolyticus Mo245 as a promising producer of both biopolymers, suitable for the valorization of glycerol, showcasing a sustainable route to yield two valuable biobased materials, an HA-like polysaccharide and P3HB, with potential for use in several applications.