Platform construction of molecular breeding for utilization of brown macroalgae

Brown macroalgae are characterized by a large size and high productivity without requiring arable land, fresh water, and fertilizer. Furthermore, since brown macroalgae contain little or no lignin, simple biorefinery processing can efficiently produce sugars from this material. Therefore, brown macroalgae have attracted attention as an alternative feedstock for bioethanol production. However, the utilization of biotechnologies previously developed for terrestrial biomass processing results in difficulties in the bioconversion of brown macroalgae. Recently, several studies have developed biotechnologies for using major carbohydrates of brown macroalgae, such as laminarin, mannitol, and alginate. This review focuses on these fermentation biotechnologies using natural or engineered microorganisms. •Biotechnologies for bioethanol production from brown macroalgae are reviewed.•Main components of brown macroalgae are laminarin, mannitol, and alginate.•Metabolic engineering enables to ferment main components of brown macroalgae.•Yeast cell surface display system enables to utilize polymers of brown macroalgae.