Macroalgae have a tremendous potential to become an important renewable resource for valuable biomolecules and chemicals. New and improved ways of cell disruption and of enhancing rate as well as yield of extraction of valuable products from macroalgae are needed to fully realise this potential. In this work, hydrodynamic cavitation (HC) was used for intensifying rate and yield of extraction of phycoerythrin, proteins and carbohydrates from marine macroalgae Palmaria palmata. We use vortex-based HC devices which do not use small restrictions like orifice-based HC devices or moving parts like rotor-stator based HC devices. A bench scale setup with a nominal slurry flow rate of 20 LPM was established. Dried and powdered macroalgae was used. Influence of key operating parameters like pressure drop and number of passes on extraction performance (the rate and yield) was measured. A simple, yet effective model was developed and used for interpreting and describing experimental data. The results indicate that there exists an optimum pressure drop across the device at which extraction performance is maximum. The extraction performance with HC was found to be significantly better than the stirred vessels. HC has resulted in 2 to 20 times improvement in the rate of extraction of phycoerythrin (R-PE), proteins and carbohydrates. Based on the results obtained in this work, pressure drop of 200 kPa and number of passes through the HC devices of about 100 were found to be most effective for HC-assisted intensified extraction from macroalgae. The presented results and model will be useful for harnessing vortex-based HC devices for intensifying the extraction of valuable products from macroalgae.

Seaweed is a resilient macrophytic plant thriving in intertidal zones. These are rapidly gaining attention due to their autotrophic nourishment, rapid growth, and minimal land requirement for cultivation. Seaweed is used in various food and non-food sectors, thus possessing immense potential as a valuable bioresource with high commercial value. However, utilizing seaweed as a bioresource comes with various challenges at processing levels, particularly at cost-effective downstream processing. Hence, this review highlights the advancement in seaweed biomass processing together with its application in food, nutraceuticals, pharmaceuticals, cosmetics, and non-food sectors. Additionally, the advancements in seaweed cultivation and the applications of seaweed in agriculture as a biostimulant, biofuel production, and packaging material are also reviewed. Finally, this review addresses the need for technology intensification, public awareness, and financial investment to enhance the commercialization and integration of seaweed-based products into the bioeconomy. The potential of seaweed to contribute to climate change mitigation and the circular economy is underscored, calling for further research and development to optimize its multifaceted applications.