Bacterial cellulose (BC) has extensive application prospects in many fields in view of its unique characteristics. However, the large-scale applications of BC are severely limited because of relatively low BC productivity and high cost of culture medium. Herein, the distiller's grain enzymatic hydrolysate (DEH) and yellow water were successfully combined as an effective substitute (the best distiller's grains-yellow water medium, BDY medium) for traditional Hestrin-Schramm medium (HS medium) for BC production by Gluconacetobacter xylinus through the response surface methodology. The BC production in BDY medium was significantly enhanced to 7.42 g/l with BC conversion yield of 42.4% after 7 days static cultivation, which was 3.72-fold and 3.37-fold higher than that in HS medium, respectively. The structure and properties of BC membranes produced in HS and BDY medium were evaluated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), thermogravimetric analysis (TGA) and hydrophilicity analysis. There was no significant difference between BC samples produced in the HS and BDY medium, indicating that BDY, as abundant and inexpensive substrates, can effectively replace HS medium to enhance BC production. The employment of distiller's grains and yellow water to BC production not only is conducive to achieve industrial production of BC, but also can effectively realize the recycling of waste from Baijiu distillery.
Keywords: Bacterial cellulose; Distillery byproduct; Increased yield; Response surface methodology; Structural analysis.