Purification and Characterization of Microbial Hyaluronic Acid by Solvent Precipitation and Size-Exclusion Chromatography

Enzyme variants in biosynthesis and biological assessment of different molecular weight hyaluronan

In the present study, low- and high-molecular-weight hyaluronic acids (LMW-HA and HMW-HA) were synthesized in vitro by truncated Streptococcus equisimilis hyaluronan synthases (SeHAS). The enzyme kinetic parameters were determined for each enzyme variant. The MW, structure, dispersity, and biological activity of polymers were determined by electrophoresis, FTIR spectroscopy, carbazole, cell proliferation, and cell migration assay, respectively. The specific activities were calculated as 7.5, 6.8, 4.9, and 2.8 µgHA µgenzyme-1 min-1 for SeHAS, HAS123, HAS23, and HASIntra, respectively. The results revealed SeHAS produced a polydisperse HMW-HA (268 kDa), while HAS123 and HAS23 produced a polydisperse LMW-HA (< 30 kDa). Interestingly, HASIntra produced a low-disperse LMW-HA. Kinetics studies revealed the truncated variants displayed increased Km values for two substrates when compared to the wild-type enzyme. Biological assessments indicated all LMW-HAs showed a dose-dependent proliferation activity on endothelial cells (ECs), whereas HMW-HAs exhibited an inhibitory effect. Also, LMW-HAs had the highest cell migration effect at 10 µg/mL, while at 200 µg/mL, both LMW- and HMW-HAs postponed the healing recovery rate. The study elucidated that the transmembrane domains (TMDs) of SeHAS affect the enzyme kinetics, HA-titer, HA-size, and HA-dispersity. These findings open new insight into the rational engineering of SeHAS to produce size-defined HA.

Selective isolation of hyaluronan by solid phase adsorption to silica

A solid phase adsorption method for selective isolation of hyaluronan (HA) from biological samples is presented. Following enzymatic degradation of protein, HA can be separated from sulfated glycosaminoglycans, other unsulfated glycosaminoglycans, nucleic acids, and proteolytic fragments by adsorption to amorphous silica at specific salt concentrations. The adsorbed HA can be released from silica using neutral and basic aqueous solutions. HA ranging in size from ∼9 kDa to MDa polymers has been purified by this method from human serum and conditioned medium of cultured cells.

A Review on Current Strategies for Extraction and Purification of Hyaluronic Acid

Since it is known that hyaluronic acid contributes to soft tissue growth, elasticity, and scar reduction, different strategies of producing HA have been explored in order to satisfy the current demand of HA in pharmaceutical products and formulations. The current interest deals with production via bacterial and yeast fermentation and extraction from animal sources; however, the main challenge is the right extraction technique and strategy since the original sources (e.g., fermentation broth) represent a complex system containing a number of components and solutes, which complicates the achievement of high extraction rates and purity. This review sheds light on the main pathways for the production of HA, advantages, and disadvantages, along with the current efforts in extracting and purifying this high-added-value molecule from different sources. Particular emphasis has been placed on specific case studies attempting production and successful recovery. For such works, full details are given together with their relevant outcomes.

Methods for isolating and analyzing physiological hyaluronan: a review

The carbohydrate hyaluronan (or hyaluronic acid, HA) is found in all human tissues and biofluids where it has wide-ranging functions in health and disease that are dictated by both its abundance and size. Consequently, hyaluronan evaluation in physiological samples has significant translational potential. Although the analytical tools and techniques for probing other biomolecules such as proteins and nucleic acids have become standard approaches in biochemistry, those available for investigating hyaluronan are less well established. In this review, we survey methods related to the assessment of native hyaluronan in biological specimens, including protocols for separating it from biological matrices and technologies for determining its concentration and molecular weight.

Validation of an Analytical Method for the Simultaneous Determination of Hyaluronic Acid Concentration and Molecular Weight by Size-Exclusion Chromatography

The hyaluronic acid (HA) global market growth can be attributed to its use in medical, cosmetic, and pharmaceutical applications; thus, it is important to have validated, analytical methods to ensure confidence and security of its use (and to save time and resources). In this work, a size-exclusion chromatography method (HPLC-SEC) was validated to determine the concentration and molecular distribution of HA simultaneously. Analytical curves were developed for concentration and molecular weight in the ranges of 100-1000 mg/L and 0.011-2.200 MDa, respectively. The HPLC-SEC method showed repeatability and reproducibility greater than 98% and limits of detection and quantification of 12 and 42 mg/L, respectively, and was successfully applied to the analysis of HA from a bacterial culture, as well as cosmetic, and pharmaceutical products.

Comparative Economic Analysis Between Endogenous and Recombinant Production of Hyaluronic Acid

Hyaluronic acid (HA) is a biopolymer with a wide range of applications, mainly in the cosmetic and pharmaceutical sectors. Typical industrial-scale production utilizes organisms that generate HA during their developmental cycle, such as Streptococcus equi sub. zooepidemicus. However, a significant disadvantage of using Streptococcus equi sub. zooepidemicus is that it is a zoonotic pathogen, which use at industrial scale can create several risks. This creates opportunities for heterologous, or recombinant, production of HA. At an industrial scale, the recovery and purification of HA follow a series of precipitation and filtration steps. Current recombinant approaches are developing promising alternatives, although their industrial implementation has yet to be adequately assessed. The present study aims to create a theoretical framework to forecast the advantages and disadvantages of endogenous and recombinant strains in production with the same downstream strategy. The analyses included a selection of the best cost-related recombinant and endogenous production strategies, followed by a sensitivity analysis of different production variables in order to identify the three most critical parameters. Then, all variables were analyzed by varying them simultaneously and employing multiple linear regression. Results indicate that, regardless of HA source, production titer, recovery yield and bioreactor scale are the parameters that affect production costs the most. Current results indicate that recombinant production needs to improve current titer at least 2-fold in order to compete with costs of endogenous production. This study serves as a platform to inform decision-making for future developments and improvements in the recombinant production of HA.

Preparation, purification, and characterization of low-molecular-weight hyaluronic acid

OBJECTIVE

The use and commercial value of hyaluronic acid (HA) as an important element in the pharmaceutical, biomedical, and cosmetics industry is because of its purity. Four recombinant strains of Corynebacterium glutamicum containing different genes were used to produce HA.

RESULTS

The production parameters were measured and strain 183.2, with the highest amount of HA (2.15 mg/ml), was selected for further experiments. HA was precipitated by different ratios of ethanol-isopropanol at 4 °C and - 20 °C. Active charcoal (1%) was added to the solvent precipitation mixture at pH 5 and 10. Finally, to achieve more purity and separation, gel filtration chromatography was used. The best result was obtained using an ethanol-isopropanol ratio of 1:1 of at - 20 °C, followed by active charcoal treatment at the acidic pH, and three fractions of the chromatography with molecular weights of 27, 27-110, and < 27 KDa were more analyzed with electrophoresis and FTIR.

CONCLUSIONS

The present study described a simple, economical, and reproducible method resulting in a high yield for low-MW HA from C. glutamicum.

Recovery and Purity of High Molar Mass Bio-hyaluronic Acid Via Precipitation Strategies Modulated by pH and Sodium Chloride

The effects of ethanol/broth proportions and the number of steps at varying pH in the presence or absence of sodium chloride (NaCl) were studied as precipitation strategies for the recovery and purification of high molar mass bio-hyaluronic acid (Bio-HA). Bio-HA was synthesized by Streptococcus zooepidemicus in a culture medium containing glucose and soy peptones. A single-step precipitation was more attractive than multistep precipitation in terms of recovery and purity as well as decreased use of ethanol. The best conditions in the absence and presence of salt were 2:1 ethanol/broth (v/v) at pH 4 (55.0 ± 0.2% purity and 85.0 ± 0.7% recovery) and 2:1 ethanol/broth (v/v) at pH 7 + 2 mol L^-1 NaCl (59.0 ± 0.9% purity and 82.0 ± 4.3% recovery). Dynamic light scattering (DLS) spectra showed different particle sizes as a consequence of the changes in the molecular structure of HA, mainly with changes in pH. Although slight changes in distribution were observed, the average HA molar mass was not affected by the precipitation strategy, remaining on the order of 10⁵ Da. Therefore, pH and NaCl modulated the precipitation performance of HA. These findings are relevant to further optimizing the precipitation step, thus minimizing costs in the later stages of HA purification.

Electrofiltration improves dead-end filtration of hyaluronic acid and presents an alternative downstream processing step that overcomes technological challenges of conventional methods

Hyaluronic acid (HA) dispersion obtained from the bacteria Streptococcus equi was concentrated by electrofiltration. In the conventional downstream processing of HA, extraction and precipitation lead to increase in environmental issues, structural changes, and time and energy related costs. Using electrofiltration as an alternative technology delivers solutions to these limitations. Experiments were conducted in order to test the applicability of electrofiltration to downstream processing of the negatively charged HA. The structural changes and molecular weight distributions, often a consequence of the employed separation method, were tested by analysis of the initial dispersions and final products. In comparison to the conventional filtration, concentration factors were increased up to almost four times without any detectable structural change in the final product.