Process–Structure–Property Engineering of Bacterial Cellulose Nanofibers via Sustainable Biosynthesis and Green Electrospinning

Abstract

Bacterial cellulose (BC) nanofibers are addressed within a unified, quantitative process–structure–property engineering framework that follows the material logic from raw feedstock, through green processing, to structure, properties, and functional applications. Upstream biosynthesis variables (strain, carbon source, culture mode, and oxygen transfer coefficient, kLa) are reframed as structural design levers that set the crystallinity index (CI, ~80–90%), the Iα/Iβ polymorphic ratio (~ 0.6–0.8), fibril diameter (~ 20–100 nm), and network density. BC is critically compared with wood-derived cellulose and other nanocelluloses to clarify its specific processability advantages and limitations. Drawing on the available literature, this review proposes an operational description of “dissolution–rheology readiness” through indicative, literature-informed rheological bands (complex viscosity η* ≈ 0.8–20 Pa·s, loss-dominated response with tanδ ≈ 1–5, relaxation time λ ≈ 1–10 ms, and conductivity κ ≈ 0.6–2.5 mS cm⁻¹) that bound stable electrohydrodynamic atomization. Process descriptions are expressed in electric field strength rather than voltage alone, and a comparative electrospinnability descriptor (D*) is proposed to enable cross-study mapping. Structure–property relationships are refined for well-defined systems (aligned vs. random, cross-linked vs. uncross-linked), and specific fiber morphologies (bead-on-string, porous, wrinkled, bimodal, core–sheath) are linked to filtration, triboelectric, wound care, and energy functions. The environmental–economic trade-offs of green solvents and scalable manufacturing routes are quantified, and a separate perspective outlines a closed-loop, digitally assisted BC fiber engineering roadmap.