Marine sponges can be regarded as a promising alternative source for collagen, with interesting prospective for biomedical applications. Although, and despite of its unique physico-chemical properties, sponge-origin collagen is not available in large quantities, mainly due to the lack of efficient extraction methodologies [1]. The traditional procedures are very laborious, time consuming and present several drawbacks that are hampering the process scale up, such as the requirement of several operational steps, energy and high volumes of water and other reagents [2, 3]. In this sense, there is a necessity for an alternative methodology comprising fewer steps and, ideally, more environmentally sustainable. We have proposed a new technology for the extraction of marine sponge collagen based on water pressurized with carbon dioxide. This new methodology is comprised by one single extraction step, under mild operating conditions. The objective of this work is to optimize the operating conditions to obtain the highest yields and collagen quantity and quality. Pressure and time were the parameters studied through a two-level factorial design performed by statistical analysis using the software Design-Expert (Stat - Ease^®). The reactor was loaded with the marine sponges and distilled water, heated to 37ºC and pressurized with CO₂. The effects of pressures ranging 10-50 bars and extraction times between 3-24 hours were studied. In this work we demonstrate that the acidification of the aqueous solution promoted by CO₂ induces collagen solubilisation in the aqueous media and the final extracts can be easily recovered after freeze-drying. The collagen content of each extract was determined using a dye-binding method (Sircol Assay). Additionally, circular dichroism analysis and Infra-red spectroscopy spectra are similar to the controls, suggesting that the original chemical structure from collagen is maintained. In overall, the results obtained have demonstrated the effectiveness and potential of this new green technology to obtain sponge-origin collagen with great applicability in the biomedical field.

[1] S. Heinemann, H. Ehrlich, Biomacromolecules 8, 3452-3457 (2007)

[2] D. Swatschek, W. Schatton, European Journal of Pharmaceutics and Biopharmaceutics 53, 107-113 (2002)

[3] C. A. Pacak, J. M. Powers, Tissue Engineering Part C Methods 17, 879-885 (2011)