Polymeric Materials Used for Immobilisation of Bacteria for the Bioremediation of Contaminants in Water

Abstract

Bioremediation is a key process for reclaiming polluted soil and water by the use of biological agents. A commonly used approach aims to neutralise or remove harmful pollutants from contaminated areas using live microorganisms. Generally, immobilised microorganisms rather than planktonic cells have been used in bioremediation methods. Activated carbon, inorganic minerals (clays, metal oxides, zeolites), and agricultural waste products are acceptable substrates for the immobilisation of bacteria, although there are limitations with biomass loading and the issue with leaching of bacteria during the process. Various synthetic and natural polymers with different functional groups have been used successfully for the efficient immobilisation of microorganisms and cells. Promise has been shown using macroporous materials including cryogels with entrapped bacteria or cells in applications for water treatment and biotechnology. A cryogel is a macroporous polymeric gel formed at sub-zero temperatures through a process known as cryogelation. Macroporous hydrogels have been used to make scaffolds or supports for immobilising bacterial, viral, and other cells. The production of composite materials with immobilised cells possessing suitable mechanical and chemical stability, porosity, elasticity, and biocompatibility suggests that these materials are potential candidates for a range of applications within applied microbiology, biotechnology, and research. This review evaluates applications of macroporous cryogels as tools for the bioremediation of contaminants in wastewater.

Polysaccharides as Support for Microbial Biomass-Based Adsorbents with Applications in Removal of Heavy Metals and Dyes

“…Substances or materials used for immobilization must meet a number of specific conditions [29][30][31] Choosing a support according to the desired application is an important task, which is why it must be considered significant the following conditions: toxicity, immobilization efficiency, stability, and microscopic properties of the particle surface, but also flexibility in overall shape, high diffusivity, simple immobilization procedure, and high biomass retention. Due to the impossibility of finding a single material that meets all these conditions, in practice, combinations of various polymers, or modifiers of support polymers properties are most often used [31][32][33].…”

“…The most important natural polymers and derivates that can be used for microbial immobilization are polysaccharides ([C n (H 2 O) n ] m , where n = 6…8 and m = 40…30,000): cellulose, chitin, chitosan (deacetylated chitin) and alginate, presented in Table 3 . These polysaccharides are characterized by biocompatibility, biodegradability, and non-toxicity, but some considerations related to mechanical straight, stability, and standardized pore size or immobilization surface need to be considered [ 32 , 33 ]. Immobilization of microorganisms in naturally polymers (such as polysaccharides) can increase the biosorption capacity of the matrices (alginate, pectate, and synthetic cross-linked polymer) up to 12-fold when compared to the use of polymers alone [ 34 ].…”

Use of PEDOT:PSS/Graphene/Nafion Composite in Biosensors Based on Acetic Acid Bacteria

“…Immobilization of bacteria has been done in a variety of ways. One of the most widespread is their entrapment into various gels [3][4][5]. Immobilization of cells into conducting gels enables the formation of electroactive biofilms.…”

Computational Study on Temperature Driven Structure–Function Relationship of Polysaccharide Producing Bacterial Glycosyl Transferase Enzyme

“…EPS are carbohydrate polymers that assist the bacterial communities to endure extreme temperature, salinity, nutrient scarcity, or presence of toxic compounds [ 3 ]. In recent years, the increased demand for biopolymers for pharmaceutical, food, and other industrial applications has led to a remarkable research interest in polysaccharide biology [ 4 , 5 , 6 ]. Substantial attention in this regard goes to the isolation and identification of new bacterial polysaccharides that might have innovative applications as gelling, emulsifying, or stabilizing agents [ 7 ].…”