Abstract: A method is provided for manufacturing a rigid object from a powder produced from shear stirred brown macroalgae so as to extract proteins, such as actin, from the brown macroalgae, the powder consisting of particles having an equivalent diameter smaller than or equal to 1.5 millimeters and having a residual moisture content smaller than or equal to 45%. The method includes thermo-compression of the powder in a mould, the powder being brought to a temperature between 50 and 100° C. and subjected to a pressure of between 150 and 4000 bars for 50 seconds to 45 minutes. Also provided is a method for preparing the powder.

Abstract: A method is provided for fabricating a rigid object from a powder produced from brown macroalgae treated with weak acids. The powder presents a particle size of between 0.5 and 1.5 millimeters and a residual moisture content of less than or equal to 26%. The method includes a step of thermocompressing the powder into a mold, the powder being brought to a temperature of between 50 and 180° C. and subjected to a pressure of between 10000 and 100000 bar for 50 to 200 seconds. A method is also provided for preparing the powder.