Marine prebiotics: Polysaccharides and oligosaccharides obtained by using microbial enzymes

•Marine algae are valuable sources of bioactive poly- and oligosaccharides.•Extraction methods can be correlated to biological activity of marine prebiotics.•The biological activity of marine prebiotics can be unravel by structural analysis.•Microbial enzymes could be used in marine prebiotics obtainment.•Microbial enzymes could be used in marine prebiotics modification.