How centrifugation influences the recovery and soy peptone incorporation in hyaluronic acid coils from fermentation

Abstract

Hyaluronic acid from fermentation (bio-HA) is a high-added-value biopolymer with a wide range of applications in aesthetic and medical areas. Bio-HA is a capsular exopolysaccharide highly hydrophilic with a coiled structure and high negative charge density at physiological pH. Centrifugation, currently used to separate microbial cells after fermentation, should significantly affect the bio-HA interactions with the medium components. Although the literature shows various centrifugation conditions for bio-HA, there is no concern about its recovery and characterization. We examined how centrifugation influences its recovery and characterized interactions with soy peptone (SP), used as a nitrogen source. We collected experimental data according to a statistical central composite design (CCD) planning with replicates at the central point with time (8-22 min) and spin (582xg to 12,402xg) as independent variables. The obtained results show bio-HA recoveries ranged from 45 ± 0.5-100% as dosed in the supernatant. The incorporation of amino acids and peptides from SP increased HA coils' density, causing losses due to sedimentation at higher spins and times. Furthermore, SP incorporation also changed the coils' size regarding HA standards of molar mass 10⁶,10⁵ and 10⁴ Da. We conclude centrifugation should significantly impact downstream processing and the total cost of bio-HA production.

Keywords: Centrifugation; Fermented broth; Hyaluronic acid; Quality; Recovery.