Added-value biorefinery products from invasive brown seaweed Rugulopteryx okamuare. A kinetic comparison

Abstract

Since 2015, the coastal area of the Strait of Gibraltar has been colonised by the Asiatic seaweed Rugulopteryx okamurae. The massive coast arrival of this brown macroalgae has seriously affected the economy of the regional fishing and touristic sectors due to its fast spreading as invasive organism. This environmental problem is, in fact, an opportunity to apply the circular economy approach. On the other hand, between 19 and 23 million tonnes of plastic waste are dumped into the sea every year due to its low biodegradability. In this context, bioplastics production through biological processes may provide a solution to this problem. Enzyme hydrolysis is one of the most well-known processes used to obtain monomeric sugars. Many of these, such as glucose D-galactose or D-mannitol are classified as fermentable sugars, which makes them a highly interesting substrate for subsequent biorefinery processes. In fact, one of the possible ways of using sugars is as a substrate for bioplastics precursors synthesis processes, such as polyhydroxyalkanoates (PHA), involving both pure cultures and mixed cultures of microorganisms. However, macroalgae cell structure is hard to fully degradate without the application of a previous pretreatment. The objective of this study is to obtain total reducing sugars (TRS) by enzyme hydrolysis (EH) from the invasive seaweed R. okamurae. In addition, two different pretreatments will also be applied and compared: microwave (MW) and biological (BIO) pretreatments.