Fundamentals and Applications of Entrapped Cell Bioaugmentation for Contaminant Removal - Emerging Environmental Technologies - page 146

extracted by a gel formable solvent. The phase separation process is quite limited in
use since the gel formable solvent could severely damage the viability of the cells.

7.2.2 Widely Used Cell Entrapment Matrices and Procedures

For environmental applications, cell entrapment matrices can be categorized into
two types: natural and synthetic. Natural matrices, such as CA, CN, agarose,
and gelatin, are polysaccharides produced from algae or seaweed while synthetic
matrices are man-made polymers, such as PVA, CTA, polyethylene glycol, and
polyacrylamide. The criteria for matrix selection are summarized in Table 7.1. The
principles, descriptions, and cell entrapment and de-entrapment procedures for only
selected matrices including CA, CN, PVA, and CTA are reviewed below. Note that
the de-entrapment process is needed for evaluating the cell number and growth
inside the matrix.

Table 7.1 Criteria for cell entrapment matrix selection

Property Criterion Reference

Surface area Large Kourkotus et al. [65]

Handling and regeneration Easy Kourkotus et al. [65]

Cell retention High Kourkotus et al. [65]

Cell viability High Kourkotus et al. [65]

Biological activity High Jen et al. [35]

Kourkotus et al. [65]

Porosity/Diffusivity High Jen et al. [35]

Kourkotus et al. [65]
Leenen et al. [79]

Mechanical and chemical stability High Kourkotus et al. [65]

Leenen et al. [79]

Preparation procedure Easy Kourkotus et al. [65]

Leenen et al. [79]

Solubility Low Leenen et al. [79]

Biodegradability Low Leenen et al. [79]

Cell growth Possible Leenen et al. [79]

Cost Low Leenen et al. [79]

7.2.2.1 Calcium Alginate

Calcium Alginate Chemistry and Gelation

Alginate is one of the pioneer materials used for cell entrapment. It is a non-
toxic natural polysaccharide extracted from brown algae, seaweed and bacteria
such as Laminaia hyperborean , Macrocystis pyrifera , Ascophyllum nodosum , and
Azotobacter vinelandii [40-42]. It is a chain of 1-4 linked β -D-mannuronate (M)

and α -L-guluronate (G) in different compositions, sizes, and patterns depending