Sustainable bacterial cellulose from grass biomass: enhanced yield, structure, and cost efficiency compared to Hestrin Schramm and Kombucha media

Abstract

Bacterial cellulose (BC) is a structurally pure, mechanically robust biopolymer with emerging applications in textiles, biomedicine, and packaging. However, commercial-scale production remains limited by the cost and inefficiency of conventional fermentation media. This study investigates the use of freshly extracted grass juice, derived from municipal grass clippings, as a sustainable and low-cost substrate for BC biosynthesis. The performance of grass-derived BC was benchmarked against Hestrin-Schramm (HS) medium and Kombucha tea under standardized, unoptimized fermentation conditions. Grass juice yielded a threefold increase in BC production (12.05 g/L) compared to HS (4.87 g/L) and Kombucha (3.06 g/L), while also achieving the highest sugar conversion efficiency. Material characterization revealed that grass-derived BC exhibited the highest crystallinity (92.5%), uniform nanofiber morphology (38.2 ± 5.3 nm), and superior mechanical properties, including tensile strength (34.73 MPa) and Young’s modulus (2.39 GPa). Thermogravimetric analysis showed comparable thermal onset temperatures to HS-derived BC (~ 260 °C), with the highest residual mass (~ 30%) observed in grass-derived samples, indicating enhanced thermal stability. A detailed upstream cost analysis demonstrated that BC production using grass juice reduced media-related costs by ~ 60-fold compared to HS medium. These findings establish grass juice as a scalable, cost-effective fermentation substrate that simultaneously enhances material performance. This work highlights the untapped potential of green waste streams, particularly grass clippings, as feedstocks for advanced fiber materials.