Freshwater algal biomass and orange and lemon peels were assessed as tissue paper pulp supplements. Cellulose and hemicellulose
contents of algal biomass were 7.1% and 16.3%, respectively, whereas for citrus peels cellulose content ranged from 12.7% to 13.6%
and hemicellulose from 5.3% to 6.1%. For all materials, lignin and ash content was 2% or lower, rendering them suitable for use as paper
pulp supplements. The addition of algal biomass to paper pulp increased its mechanical strength significantly. However, brightness was
adversely affected by chlorophyll. The addition of citrus peels in paper pulp had no effect on breaking length, increased bursting strength
and decreased tearing resistance. Brightness was negatively affected at proportions of 10%, because citrus peel particles behave as coloured
pigments. The cost of both materials is about 45% lower than that of conventional pulp, resulting in a 0.9–4.5% reduction in final
paper price upon their addition to the pulp.