Method for producing sodium alginate microcapsules of homogeneous composition

Abstract

The invention relates to a method for producing sodium alginate microcapsules of homogenous composition that contain an enzyme extract of which the composition includes the activity of an enzyme of extracellular proteins expressed by microorganisms that break down lignocellulose material, which includes an extract obtained from fungal secretion, an alginate salt preparation dissolved under agitation, and the resuspension, drying and sorting of the microcapsules.

Description

[0001] Procedure for the preparation of sodium alginate microcapsules of homogeneous composition

[0002] The present invention relates to a process for obtaining microcapsules containing an enzyme extract that includes in its composition the activity of an extracellular protein expressed by the endophytic fungus Pestalotiopsis microspora. The complex catalyzes the oxidation of phenolic hydroxyl groups to phenoxy radicals while oxygen (O2) is reduced to water, useful for the treatment of wastewater that presents contamination by color, chemical oxygen demand and biological oxygen demand; also, a process for the preparation of microcapsules and their use for the treatment of residual effluents is revealed.

[0003] Background and Description

[0004] Textiles have been used by humanity since around 5000 BC. This industry, which was originally domestic and family-based, changed after 1500 when the first factory was established. However, spinning and weaving machinery did not appear until the Industrial Revolution in the 18th century (Neefus, JD, "Textile Industrial Processes," in Industrial Hygiene Aspects of Plant Operations, Volume 1, 1982). Textile production requires a large number of unit operations that use cotton, wool, synthetic fibers, or mixtures of these as raw materials, with a highly varied environmental impact from their liquid effluents. These effluents contain salts, starch, peroxides, EDTA, surfactants, enzymes, dyes, metals, and other organic compounds with varied structures that originate from the different stages of the overall process (Mansilla, HD, et al., "Treatment of liquid waste from the cellulose and textile industry" in Pollutant Removal by Heterogeneous Photocatalysis, CYTED, 2001).

[0005] The process requires a quantity of water that varies depending on the specific processes and the equipment used by the plant. For example, dyeing with disperse dyes uses between 100 and 150 liters of water per kilogram of product. Dyeing with reactive dyes uses between 125 and 170 liters per kilogram of product (EPA Profile of the Textile Industry, 1997).

[0006] Most of the dyes currently used in the textile industry are synthetic, water-soluble, highly resistant to chemical agents, and poorly biodegradable. Approximately 60% of the dyes in use contain highly reactive azo, anthraquinone, or phthalocyanine groups in their structure, which form an ether-type bond with the fiber (Mansilla, H.D., et al., "Treatment of liquid waste from the cellulose and textile industry" in Pollutant Removal by Heterogeneous Photocatalysis, CYTED, 2001).

[0007] Various physicochemical techniques are used for the removal of synthetic dyes, such as coagulation and flocculation combined with filtration and flotation, precipitation-flocculation with Fe(ll) / Ca(OH)2, ozone oxidation, membrane filtration and reverse osmosis, among others, which produce good quality effluents (Fernández, JA, et al. Rev. Colomb. Biotecnol. 2009), all of these techniques are usually quite expensive.

[0008] Efforts to seek treatment alternatives such as the use of biological treatments can be more economical since they use low-cost raw materials and are more environmentally friendly (Moeller, G., Garzón, M. Anuario Imta, 2003).

[0009] The microorganisms (MO) most commonly used in the bioremediation of contaminated effluents are fungi. Endophytic fungi are characterized by their ability to degrade lignin and other tree components such as cellulose. They produce extracellular enzymes that oxidize phenolic compounds. Among the characterized enzymes are manganese peroxidases, lignin peroxidases, peroxide-producing enzymes, and laccases. The activity of these MOs on dyes is based on the non-specificity of the enzyme system to depolymerize and mineralize lignin (Moeller, G., Garzón, M. Anuario Imta, 2003).

[0010] Given the ability of these fungi to secrete enzyme complexes with activity on pigments, a protocol was implemented to immobilize the enzyme extracts in sodium alginate microencapsulates. The second stage of the process involves contacting the wastewater with the microencapsulates. The fungi are cultivated at temperatures between 20 and 30°C, using nitrogen, carbon, and mineral salt sources for their growth. During the treatment process, the enzymes can be added to the pretreated water in encapsulated form. The polymers comprising these matrices are manufactured from biodegradable, natural, and nontoxic materials and are selected from the group consisting of alginates, maltodextrins, corn starch, kappa carrageenan salts, and iota carrageenan salts.

[0011] Patent W003 / 035561 also points out that it is possible to use the activity of hydrolytic enzymes, cellulolytic enzymes and ligninolytic enzymes to achieve the elimination of contaminants.

Claims

CLAIMS 1. A process for the production of sodium alginate microcapsules of homogeneous composition containing an enzymatic extract that includes in its composition the activity of an enzyme of extracellular proteins expressed by microorganisms that degrade lignocellulosic material. Said process INCLUDES: an extract obtained from the secretion of the fungus, a preparation of alginate salt dissolved under stirring, and the resuspension, drying and selection of the microcapsules. The complex catalyzes the oxidation of phenolic hydroxyl groups to phenoxy radicals while oxygen (O2) is reduced to water.

2. A process according to claim 1, characterized in that to obtain the composition according to claim 1, it begins with the extract obtained from the secretion of the fungus or endophytic fungi or other microorganisms, when it has been cultivated in a specific medium containing a textile dye as a carbon source (1).

3. A process according to claim 2, characterized in that a solution preparation of an alginate salt (sodium alginate) at 1.5% is prepared, and dissolved under stirring at room temperature (2), incorporating the protein extract into a 2% calcium acetate solution (3).

4. A method according to claim 3, characterized in that the formed and isolated microcapsules (4) (5) are resuspended with the preparation and subsequently dried for 30 to 120 minutes (6).

5. A method according to claim 4, characterized in that the fraction of microcapsules with a size between 250 and 1000 microns (7) is selected, discarding the microcapsules with a size less than 250 microns and with a size greater than 1000 microns, separating and storing the microcapsules for later use (8).

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