Multistage extraction and purification of waste Sargassum natans to produce sodium alginate: An optimization approach

Abstract

Sargassum in the Caribbean region has affected the livelihood of several coastal communities due to the influx of large quantities of the seaweed in recent times. This article seeks to explore how waste Sargassum natans can be utilized to produce sodium alginate. The novelty in this research lies in the optimization process, whereby multistage extraction and precipitation were investigated over commonly used single stage processing, in an effort to maximize both yield and purity. The results showed that a maximum yield of 19% was observed after 1 stage, while the purity was 74% after 4 stages. In addition, optimization of the multistage precipitation process using the Global Optimization Toolbox in MATLAB R2017b provided a novel model which indicated that a compromise between the maximum purity and yield can be obtained at 3 stages; 71-74% and 12-16% respectively. Furthermore, characterization was done using FTIR and NMR, with results comparable to a commercial sodium alginate brand, giving absorption bands at 1610 cm and 1395 cm and an M/G ratio of 0.51 respectively.

Biomass composition of the golden tide pelagic seaweeds Sargassum fluitans and S. natans (morphotypes I and VIII) to inform valorisation pathways

“…This polysaccharide is one of the most versatile polymers, historically used in a wide ranges of industries (food, feed, textile printing, papermaking and pharmaceutical), and with more recent applications in the biomedical and bioengineering fields (Peteiro et al 2018). Interestingly, recent work using S. natans harvested in the Caribbean suggested that sodium alginate extracted from this species could be used as an alternative for packaging and encapsulation (Mohammed et al 2018), and calcium alginate could be considered as a successful biosorbent of heavy metals ions (Mohammed et al 2019).…”

Pharmacological and natural products diversity of the brown algae genusSargassum

“…Sodium alginate was detected in S. natans collected from both Manzanilla and Mayaro Bays (Trinidad). 70…”

Application of Chitosan/Alginate Nanocomposite Incorporated with Phycosynthesized Iron Nanoparticles for Efficient Remediation of Chromium

“…The extraction of sodium alginate (Alg) was performed from Sargassum linifolium, using slightly modified protocols [ 21 , 43 ]. Briefly, collected seaweed biomass (100 g) was recurrently cleansed with DW, air-dried and soaked in 1 L of 2% formaldehyde solution for 14 h to eradicate pigments, then washed with DW and immersed in 0.2 M H 2 SO 4 solution (at 1:10 w/v ) before keeping for 2 h. Next, samples were further rinsed by DW and extracted with 5% Na₂CO₃ solution for 6 h under agitation.…”

“…Alginate (Alg) is the extracted hydrophilic polysaccharide from brown macroalgae. This linear biopolymer composition contains uronic acids, α-l-guluronic acid, and 1,4-linked-β-d-mannuronic acid [ 21 ]. Alg properties include non-toxicity, biodegradability, mucoadhesion and biocompatibility, which advocate its biomedical, nutraceutical, pharmaceutical and environmental applications [ 22 ].…”