*3.2.3 Algae*

Some algae have been shown to produce secondary metabolites that can biodegrade microplastics. For example, *Phormidium lucidum* and *Oscillatoria subbrevis* can biodegrade PE and LDPE [84]. Algal biofilms formed by *Discostella spp.*, *Navicula spp.*, *Amphora spp.*, and *Fragilaria spp.* have shown to degrade LDPE, PP, and PET in the marine environment [85]. Once forming a biofilm on the plastic surface, algae utilize the carbon present on the plastic as a source of nutrition, thus weakening the strength of the plastic and making it fragile. Moreover, algae produce extracellular polymeric substances and enzymes such as PETase that result in the degradation of PET [86]. Plastic degradation by algae is still in its nascent phase and needs further research.
