The need for circular textiles has led to an interest in the production of biologically derived materials, generating new research into the bioproduction of textiles through design and interdisciplinary approaches. Bacterial cellulose has been produced directly from fermentation into sheets but not yet investigated in terms of producing filaments directly from fermentation. This leaves a wealth of material qualities unexplored. Further, by growing the material directly into filaments, production such as wet spinning are made redundant, thus reducing textile manufacturing steps. The aim of this study was to grow the bio-material, namely bacterial cellulose directly into a filament. This was achieved using a method of co-designing with the characteristics of biological materials. The method combines approaches of material-driven textile design and human-centred co-design to investigate co-designing with the characteristics of living materials for biological material production. The project is part of a wider exploration of bio-manufacturing textiles from waste. The practice-based approach brought together biological sciences and material design through a series of iterative experiments. This, in turn, resulted in designing with the inherent characteristics of bacterial cellulose, and by doing so filaments were designed to be fabricated directly from fermentation. In this investigation, creative exploration was encouraged within a biological laboratory space, showing how interdisciplinary collaboration can offer innovative alternative bioproduction routes for textile filament production.

There are difficulties in measuring the molecular weight (Mw) of bacterial cellulose (BC) using Gel Permeation Chromatography (GPC) analysis. Additionally, the Mark-Houwink-Sakurada equation cannot be used to predict the Mw of BC as no Mark-Houwink-Sakurada constant specific to BC is available. In this study, a systematic approach is developed to establish the relationship between the Mw of BC and the viscosity of its copper (II) ethylenediamine (CED) solutions. Impurities contained in the raw BC are examined and appropriate purification procedures are designed for their removal before the above two measurements are conducted. The Mw of BC is obtained by measuring the Degree of Polymerization of its corresponding cellulose acetate (CA), derived from degraded BC, using GPC analysis, and the viscosity of the CED solutions of the BC is measured using a BS/U Tube viscometer. In this paper, the Mark–Houwink–Sakurada constants (K=0.3752 mL/g and $$\alpha$$α =1.4532) specific for BC are determined to relate the Mw of BC with the intrinsic viscosity of its CED solutions. It is also found that the Mw of BC is proportional to the dynamic viscosity (i.e., $$\eta _{BC} =0.0183Mw^{1.3069}$$η BC = 0.0183 M w 1.3069 ) and the flow time (i.e., $$t_{BC} =1.3809$$t BC = 1.3809 Mw $$^{1.3062}$$1.3062 ) of its CED solutions. These BC-specific relationships can help determine the Mw of BC from the rheological properties of its CED solutions.