Preparation of stable alginate gel beads in electrolyte solutions using Ba2+ and Sr2+

Abstract

Alginate solutions with two different M/G (mannuronic acid/guluronic acid) ratios were added dropwise to SrCl 2 and BaCl 2 solutions. The low M/G ratios(0.27) St-and Ba-alginate gel beads were more chemically and physically stable in electrolyte solutions than conventional Caalginate gel beads. These gel beads with immobilized yeast cells had normal ethanol productivities.

Biodegradation of wastewater pollutants by activated sludge encapsulated inside calcium-alginate beads in a tubular packed bed reactor

“…Based on the results, the gelation period should be increased or the temperature changed to avoid the erosion of the calcium-alginate beads. Other alternative to increase the mechanical strength of the spheres could be use Sr 2 , because both, the chemical strength and the mechanical strength of Sr-alginate are known to be superior to those of Ca-alginate (Tanaka and Irie 1988;Sakurai et al 1999). Figure 5, shows the COD variation as a function of the time and distance (ports) in the reactor.…”

Studies on citric acid production with immobilized Yarrowia lipolytica in repeated batch and continuous air-lift bioreactors

“…Tanaka and Irie (1988) successfully substituted strontium and barium for calcium, but this type of biocatalyst bead would not be acceptable for citric acid production for the food industry. Consequently, the possibility of using glutaraldehyde to harden the alginate beads was investigated.…”

Tissue transplantation by stealth—Coherent alginate microcapsules for immunoisolation

“…Barium cross-linking enhances in vitro and in vivo long-term integrity compared to calcium [72,73], with barium alginate microcapsules used to protect allogeneic pancreatic islets for up to 350 days in a murine model [74]. Although to a lesser extent than the other high affinity options, Ba 2+ ions are toxic [75,76].…”

“…With a weak polyelectrolyte attachment, the membrane detaches quickly and frequently after implantation. Various strategies for enhancing mechanical strength and long-term stability of alginate microcapsules have been studied in the past, including the use of different multivalent cations to form the core alginate hydrogel [72,74], different polycations on the alginate microcapsules [138], and tailor-made alginate to enhance the binding of PLL onto the alginate microcapsules [139]. More recently, Dusseault et al have demonstrated that covalently cross-linked alginate/PLL multilayer capsules [140] are sufficiently robust to prevent breakout of tumorigenic EL-4 thyoma cells, while the process itself is mild and does not adversely affect islet viability or function [141].…”