The Development of a Greener Alginate Extraction Process for Pharmaceutical Application

  • Sijin Saji

Student thesis: Master's Thesis


Currently, alginate is extracted using various conventional methods in which toxic chemicals such as formaldehyde are widely used in the process to enhance the extraction process. Furthermore, significant amounts of water and organic solvent are consumed throughout the process, making the alginate extraction process costly and environmental un-friendly. In this study alternative seaweed pre-treatment techniques have been explored by using a high temperature, short reaction time and assistance with seawater pre-treatment process. Firstly, preliminary experiments were conducted using an alkali (NaOH) based pre-treatment method to understand the impact of various parameters in the pre-treatment, extraction, purification and drying steps on the alginate extraction yield and alginate physiochemical properties (mainly dynamic viscosity). In summary, it was found that at pre-treatment at 70oC at 2 minutes and 1% concentration of NaOH was the best condition. At the extraction stage, using Na2CO3 at 40oC for 2 hours and drying conditions of 40oC in an oven yielded good alginate with high dynamic viscosity. Next, Design of experiments (DOE) for the optimisation of pre-treatment using citric acid was conducted. The result showed that pre-treatment using 1% (w/v) citric acid at 50oC for 4 minutes was able to produce alginate sample with a molecular weight comparable with commercial sodium alginate samples with low to medium viscosity. Then scaled up lab experiments were conducted using Alkali/citric acid with seawater/deionised water using the optimum conditions discovered above. The alginate samples were characterised using NMR, DSC, TGA, SEC-MALLS. The alginate samples were used for producing foams and then the drug release profiles of the alginate samples were investigated using curcumin as example. It was found alkali with seawater pre-treatment condition led to the best alginate sample, which formed a drug carrier released 80% of curcumin over the period of 2 hours. Physicochemical properties of alginate fibres and films were also characterised and their application in drug release was tested as well. In summary, alginate with various properties have been extracted from brown seaweed via greener alginate extraction processes developed in this study. The alginate samples have been demonstrated to be able to use in pharmaceutical application.
Date of Award3 Nov 2022
Original languageEnglish
SupervisorChenyu Du (Main Supervisor) & Parikshit Goswami (Co-Supervisor)

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