The objective of this work is to develop and optimize a new technology for extraction of acid soluble compounds, based on water pressurized with carbon dioxide. To prove the concept, we have applied this new process to marine sponges and have successfully obtained collagen/gelatin with properties for application in the biomedical field. Traditionally, marine sponge collagen/gelatin can be isolated after acid, basic or enzymatic treatments processes, all of which require heat or water. Nonetheless, the extraction procedures are very laborious and involve multiple steps, which hinder the scaling up of the processes. The most explored extraction process for this material is typically performed in a two-step process that includes extraction/dissolution in alkaline aqueous media together with a chaotropic agent in high concentration, followed by precipitation under acidic medium. This process is time consuming and requires the use of chemicals and large quantities of water, prompting the need for an alternative process comprising less steps and, ideally, more environmentally friendly. In this sense, we propose a new extraction methodology, under mild operating conditions, in which water is acidified with CO2 to promote the extraction of collagen/gelatin from different marine sponge species.