Biocircular economy-driven bacterial cellulose with large pore size: statistical optimization using Glutamicibacter soli bread waste hydrolysate

Abstract

Bacterial cellulose (BC) is a versatile biopolymer of considerable biotechnological interest, with wide-ranging applications in biomedical, industrial, and engineering fields attributable to its exceptional structural and physicochemical properties. Despite its promise, the high cost of conventional production media and the challenge of tailoring BC structural characteristics remain critical bottlenecks limiting sustainable large-scale manufacturing. In the present study, a novel fermentation medium based on Glutamicibacter soli bread waste hydrolysate (BWH) was developed and statistically optimized for high-yield BC production by Komagataeibacter sp. strain HIJ12 EMCCN-4085, integrating circular bioeconomy principles through food waste valorization. One-variable-at-a-time (OVAT) screening identified glycerol and ethanol supplementation, incubation at 28 °C, pH 5.5, a 2-day-old inoculum, and an aeration ratio of zbroth: flask volume) as the key determinants governing BC biosynthesis. Subsequent Box–Behnken design-based Response Surface Methodology, supported by canonical and ridge analyses, refined glycerol concentration, inoculum size, and incubation time, yielding an exceptional BC dry weight of 39 g L−1 within 5.8 days, substantially surpassing most reported waste-based BC systems that typically achieve 4–15 g L−1 over longer fermentation periods. Structural characterization demonstrated that hydrolysate-based BC possessed a distinctively large pore size, enhanced porosity (41 ± 1.2%), and reduced crystallinity relative to conventional Hestrin–Schramm-based BC, while fully preserving the characteristic cellulose chemical structure, properties particularly advantageous for drug delivery, wound healing, and filtration applications. Collectively, these findings establish G. soli BWH as a high-performance, sustainable fermentation substrate that simultaneously enhances BC productivity and tailors material properties, offering a compelling strategy for converting food waste into high-value biomaterials. G. soli bread waste hydrolysate established as a biocircular BC production substrate. Box–Behnken RSM with ridge analysis achieved exceptional BC yield of 39 g L−1. Optimized yield represents a 10-fold enhancement over the unoptimized baseline. BC production achieved within 5.8 days, outperforming conventional HS medium. Hydrolysate-based BC exhibited larger pore size and enhanced porosity (41%). Reduced crystallinity (54%) preserved cellulose I structure for biomedical applications. G. soli bread waste hydrolysate established as a biocircular BC production substrate. Box–Behnken RSM with ridge analysis achieved exceptional BC yield of 39 g L−1. Optimized yield represents a 10-fold enhancement over the unoptimized baseline. BC production achieved within 5.8 days, outperforming conventional HS medium. Hydrolysate-based BC exhibited larger pore size and enhanced porosity (41%). Reduced crystallinity (54%) preserved cellulose I structure for biomedical applications.