The main ethical issues around the use of algae and cyanobacteria lie around the technique of genetic modification of the organisms. This can be concluded from the vast resistance that GM crops have encountered in the EU since the 90’s.
When a gene is inserted into an organism a marker must be used, to be certain that the gene is actually transferred. These DNA markers are in nearly all cases antibiotic resistance genes. Screening happens by growing the organism on plates with antibiotics. Only the organisms who are now resistant to the drug, through the newly acquired gene, survive. Most scientists believe that there is little risk that genes are able to transfer from plants to bacteria, which would make them resistant as well.[1]
A lot of the current research is focusing on increasing the yield in photosynthetic organisms. It is assumed that the characteristics that are found in one of the model plants can be transported to other species. This is achieved most easily through genetic modification, but that is not the only way. In this chapter the main focus is on GM techniques, because of the societal resistance they encounter. Scientists in the EU often try to avoid GM, partly because of the public opposition, and because of the available alternatives. Examples of these alternatives are the artificial lighting used in horticulture and directed breeding. In this modern form of breeding, plants are screened for specific beneficial genes. Botanists can then cross selectively with these plants. Technically, no GMO is created but the plant will have the gene of interest.
The main ethical issues lie, just as with the algae and cyanobacteria, around the technology of genetic modifications.
[1] For an overview see Nicolia and et al. 2013