Plant extraction methods like enzymatic extraction (Laminaria japonica with alginate lyase), co-extraction (Laminaria digitata combining enzymatic and solvent methods), and supercritical CO2 extraction (rosehip, sea buckthorn for carotenoids, tocopherols) isolate bioactives, enhancing yield, purity, and bioactivity.

1. Enzymatic Extraction
Enzymatic extraction utilizes specific enzymes to degrade plant cell walls, releasing intracellular compounds more efficiently than traditional methods. For Laminaria japonica (kelp), Dora Agri employs enzymatic hydrolysis with alginate lyase, which breaks down alginate in the cell walls into water-soluble oligosaccharides. This process, conducted at controlled temperatures (e.g., 25–40°C) and pH (typically 5–7), reduces viscosity, enhances water solubility, and increases the release of nutrients like minerals (calcium, manganese, zinc) and polysaccharides (laminarin). The method involves soaking the kelp in a dilute acid (e.g., 0.5 wt% H2SO4) to soften the matrix, followed by enzymatic treatment, filtration, and analysis of the extract’s nutrient profile. This technique is particularly effective for marine algae, where tough cell walls hinder conventional extraction. [Ref web ID: 3]

For Laminaria digitata, enzymatic extraction often focuses on isolating laminarin, a bioactive polysaccharide. The process may involve ultrasound assistance to enhance efficiency, where high-frequency pulses (10–20 kHz) create cavitation, breaking cell walls and improving mass transfer. A study optimized laminarin extraction from Laminaria digitata using hydrochloric acid and ultrasound, achieving a yield of 57.34% and purity of 81.10%. The extracted laminarin, with a molecular weight of 5.78–5.88 kDa, is purified using membrane ultrafiltration, which separates the polysaccharide from impurities more effectively than ethanol precipitation or freeze-drying. [Ref web ID: 19]

2. Co-Extraction
Co-extraction combines multiple extraction techniques to maximize the recovery of diverse compounds from a single plant matrix. For Laminaria digitata, a combined process of de-algination followed by enzymatic saccharification has been used to extract alginate and glucose. De-algination involves acidification (e.g., 0.5 wt% H2SO4 for 2 hours) to break down the algal matrix, followed by alkaline extraction with 2.4 wt% Na2CO3 at 70°C for 100 minutes, yielding 70.1% alginate. The remaining biomass, enriched to 38% glucan, undergoes enzymatic hydrolysis with cellulases, converting glucan into glucose (96.8% digestibility) within 9 hours. This method enhances the yield of both polysaccharides and sugars, making it ideal for biorefinery applications. [Ref web ID: 18]

Co-extraction can also pair enzymatic methods with solvent-based techniques. For example, enzyme-assisted supercritical fluid extraction (EASFE) pre-treats plant material with enzymes like cellulase or pectinase to degrade cell walls, followed by CO2 extraction to isolate lipophilic compounds. This approach has been applied to other plants (e.g., pomegranate peel) but could be adapted for Laminaria digitata to co-extract laminarin and lipids, improving overall yield and bioactivity. [Ref web ID: 20]

3. Supercritical CO2 Extraction
Supercritical CO2 (SC-CO2) extraction uses CO2 above its critical point (31.2°C, 7.38 MPa) as a solvent to extract lipophilic compounds, offering a green, solvent-free alternative to conventional methods. For sea buckthorn pomace, SC-CO2 extraction at 35°C and 45 MPa yields oleoresins rich in carotenoids (396.12 mg/g D.W.), tocopherols (82% α-tocopherol), and phytosterols, with an antioxidant activity of 32.10 mMol TEAC/g D.W. The process involves passing SC-CO2 through the plant material in an extraction reactor, where it dissolves bioactives like zeaxanthin, β-carotene, and lycopene. The CO2 is then decompressed in separators (e.g., S40, S45), allowing the extract to be collected without solvent residue as the CO2 evaporates. [Ref web ID: 4]

For rosehip, SC-CO2 extraction similarly targets lipophilic compounds like essential oils and carotenoids, though specific data on rosehip extraction wasn’t detailed in the provided references. However, the method’s principles apply: SC-CO2 at optimized conditions (e.g., 35–40°C, 30–45 MPa) extracts bioactives with high purity, as seen in related studies on sea buckthorn, where yields of 67.6 g/kg D.W. were achieved. The process is adjustable by varying temperature and pressure to target specific compounds, and its non-toxic nature makes it ideal for food, cosmetic, and pharmaceutical applications. [Ref web ID: 14]

Enhanced Yield and Purity
Enzymatic extraction of Laminaria japonica increases mineral content (e.g., calcium by 2.2 times, manganese by 5.5 times) and improves water solubility of bioactives, making them more bioavailable for skincare and health products. [Ref web ID: 3]
Co-extraction of Laminaria digitata achieves a 70.1% alginate yield and 96.8% glucan digestibility, maximizing resource utilization for biorefinery applications. [Ref web ID: 18]
SC-CO2 extraction of sea buckthorn yields high-purity oleoresins (396.12 mg/g carotenoids), ensuring potent antioxidant activity for cosmetic formulations. [Ref web ID: 4]
Sustainability and Eco-Friendliness
SC-CO2 extraction leaves no solvent residue, as CO2 evaporates post-extraction, making it a green alternative for rosehip and sea buckthorn processing. [Ref web ID: 14]
Enzymatic methods reduce the need for harsh solvents, minimizing environmental impact, as seen with Laminaria japonica extraction. [Ref web ID: 3]
Improved Bioactivity and Functionality
Laminarin from Laminaria digitata exhibits high cytotoxicity against cancer cells (A549, A431, Caco-2), offering potential in pharmaceutical applications. [Ref web ID: 19]
Sea buckthorn extracts, rich in α-tocopherol (82% of tocopherols), provide vitamin E activity to combat deficiency diseases, enhancing their use in nutraceuticals. [Ref web ID: 4]
Versatility Across Applications
Enzymatic extracts from Laminaria japonica (e.g., laminarin) are used in green pesticides due to their antimicrobial properties, supporting sustainable agriculture. [Ref web ID: 3]
SC-CO2 extracts from sea buckthorn and rosehip, containing carotenoids and tocopherols, are ideal for skincare (anti-aging, antioxidant) and food industries (natural coloring, supplements). [Ref web ID: 14]
Preservation of Sensitive Compounds
SC-CO2 extraction’s low temperatures (e.g., 35°C) preserve heat-sensitive compounds like carotenoids in sea buckthorn, ensuring their efficacy in final products. [Ref web ID: 4]
Enzymatic extraction avoids high temperatures, preserving the bioactivity of polysaccharides like laminarin in Laminaria digitata.

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