Extraction of Mycosporine-like Amino Acids and Proteins from the Agarophyte Gelidium corneum Using Pulsed Power Techniques.

Gelidium corneum (syn. sesquipedale) is an industrially and ecologically important species of red alga used for the production of high-quality agar. However, the species is also of growing interest for the production of other valuable compounds, such as mycosporine-like amino acids (MAAs), with potential cosmeceutical and biomedical applications. Novel methods using two pulsed power techniques, high-voltage electrical discharges (HVED) and pulsed electrical fields (PEF), were evaluated for efficacy of MAA extraction. Algal suspensions were prepared at two ratios (1:20 and 1:40 w:v). Four different extraction protocols were compared: (i) high-voltage electrical discharges, (ii) pulsed electric fields, (iii) maceration at room temperature, and (iv) maceration at 50 °C. The algae were treated in three states: freshly harvested, dried, and powdered. HVED and PEF treatments were effective when performed on fresh algae, and in particular the HVED treatment resulted in yields of MAAs twenty times higher than the control: 0.81 ± 0.05 mg/gDry Weight (DW) vs. 0.037 ± 0.002 mg/gDW. This effect was not observed to the same extent when the algae were dried or powdered, although HVED remained the most selective method overall.

Experimental studies and simple numerical modeling of underwater electric discharges.

At present, underwater electric pulsed discharges are used in a wide range of modern applications. During the development of a system for generating underwater acoustic pressure pulses, a numerical model is an essential tool for guiding the design and interpreting the data. Developing a complex one-dimensional numerical code, like those presented in the literature, requires a substantial dedicated effort. Unfortunately, previous work trying to use simple and elegant theoretical models developed many decades ago reported a fundamental issue, apparently related to the input data. The present work performs a detailed analysis of the real meaning of the voltage measured across an underwater discharge and clarifies the correct way the power input to a simple two-phase model should be calculated. Based on accurate measurements, a phenomenological methodology to obtain the input data is demonstrated, with theoretical predictions obtained from the simple two-phase model being successfully compared with the experimental evidence obtained from both the present work as well as from other reliable data presented in the literature.