Improved growth and harvesting of microalgae Chlorella vulgaris on textile fabrics as 2.5D substrates

The green microalgae Chlorella vulgaris can be used in diverse applications from food to biofuel production. Growing them in suspension leads to challenging harvesting and processing. One possibility to overcome these problems is growing them as biofilms, i.e. adhering on a surface. While previous experiments of several research groups concentrated on flat, rigid surfaces, partly chemically modified, here the possibility to grow them on different textile substrates was investigated which were shown to be suitable as substrates for germination and growth of higher plants. Microalgae were counted after one week, subdivided into adhered and suspended ones, to evaluate the ideal substrate for cultivation and harvesting. The results show clear differences between the different woven and knitted fabrics from diverse materials, indicating that especially an open-pore jute woven fabric increased the overall algae concentration by approx. a factor of 2 and increased the adhesion of C. vulgaris by a factor of 5-10, as compared to most other textile substrates under investigation, followed by two other hairy knitted fabrics. Such textile fabrics can thus be suggested as possible substrates for improved growth and harvesting of this microalga.