Production of textile fibres from filamentous fungi grown on apple pomace : invertase pre-treatment

Abstract: In this work Rhizopus Delemar was grown on an apple pomace medium, a waste product from the juice industry. The apple pomace was pre-treated with the enzyme invertase to hydrolyse the sucrose available in the waste to glucose and fructose, which are digestible by the fungus. Combination of invertase pre-treatment and yeast extract supplementation, resulted in highest biomass growth which was 4.3 ± 0.5 g/l biomass. The fungal cell wall was separated from fungal biomass using an alkali treatment. A hydrogel was formed from the cell wall material and used for spinning of filaments using dry gel spinning. The average dry weight percentage of the gel was 11.6 ± 1.3 %. The gel was spun through a needle to a collecting rotating surface to make filaments. The filaments were easy to spin and to collect continuous fibres. The spun filaments had a rubber-like texture. All the tested filaments had an ultimate tensile strength approximately 2-3 MPa and 10 – 12% elongation at break. The conclusion of this work is that it is possible to produce fibers from fungi grown in apple waste and that it is possible to improve fungal growth using invertase and yeast extract. The tensile strength of the filaments needs further improvement to compete with other materials used in woven fabrics.