Algae as a resource


For most people, algae usually seem rather unattractive – for instance, when they proliferate to form a colossal algal bloom near the coast, and in particular close to beaches. However, in future, carpets of algae may be used as a valuable source of material for industry. “In order to use algae, you need to break down the large molecules that they produce into usable individual components,” explains Christian Stanetty from the Institute of Applied Synthetic Chemistry at TU Wien. “This is a highly complicated process but, fortunately, we have nature as an example: that’s to say, certain bacteria can do this brilliantly.”

The international research team deciphered the way the marine bacteria Formosa agariphila degrades the polysaccharide ulvan, which is produced by the algae Ulva in up to 30% of its dry weight. This degradation process is a little chemical magic trick: in a series of steps, twelve different enzymes are employed to break down the macromolecule into ever smaller building blocks. “Our task at TU Wien was to clarify, with the help of nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry, what these building blocks look like, exactly,” says Christian Stanetty. “There were a few surprises along the way with several of the degradation products looking different to what we had expected. This demonstrated that the bacteria take different chemical pathways during the degradation of the sugar than we had expected.”

In this way, the researchers were able to find out which enzymes the bacteria use in the respective steps. “As a result, we now not only understand how these microorganisms gain access to this source of nutrition. We now also have access to a toolbox consisting of a whole spectrum of new biocatalysts, thus opening up the possibility of using this complex marine polysaccharide in a targeted manner as a resource for fermentations,” says Prof. Uwe Bornscheuer from the University of Greifswald.

Source: Algae as a resource: Chemical tricks from the sea