Provided are biomass-based materials and valuable uses of microalgal biomass including: (i) acetylation of microalgal biomass to produce a material useful in the production of thermoplastics; (ii) use of triglyceride containing microalgal biomass for production of thermoplastics; (iii) combination of microalgal biomass and at least one type of plant polymer to produce a material useful in the production of thermoplastics; (iv) anionization of microalgal biomass to form a water absorbant material; (v) cationization of microalgal biomass, and optional flocculation, to form a water absorbant material; (vi) crosslinking of anionized microalgal biomass; (vii) carbonization of microalgal biomass; and (viii) use of microalgal biomass in the making of paper.