Production of probiotic bacterial cellulose with improved yield, mechanical properties, and antibacterial activity from cost-effective coculture and mixed-culture fermentation in coconut water by Komagataeibacter xylinus MSKU 12.

We successfully enhanced bacterial cellulose (BC) production in low-cost coconut water (CW) at 37 °C by low-nutrient adaptation of Komagataeibacter xylinus MSKU 12. In this study, the BC yield was significantly increased by simultaneous coculture fermentation of MSKU 12 with Saccharomyces bayanus in Hestrin-Schramm (HS) and CW media. Coculture fermentation at 30 °C produced BC yields of 13.44 and 12.13 g/L dry weight in HS containing 0.5 % acetic acid, 3 % sucrose, and 0.5 % ammonium sulfate (HS0.5A3S0.5N) after 9 days of incubation and in CW containing 0.5 % acetic acid, 3 % sucrose, and 0.5 % ammonium sulfate (CW0.5A3S0.5N) after 12 days of incubation. Moreover, at 37 °C, relatively high amounts of BC (8.64 and 7.89 g/L dry weight) were obtained from coculture in HS0.5A3S0.5N and CW0.5A3S0.5N, respectively, after 12 days of cultivation. Coculture fermentation not only increased the BC yield but also altered the properties of BC, resulting in finer microfibrils, higher mechanical strength, and stronger antibacterial activities. Both fresh and freeze-dried probiotic BC from the simultaneous mixed-culture fermentation of MSKU 12, S. bayanus, and Pediococcus pentosaceus DMKU 14-7 exhibited strong inhibitory effects against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. These results provided insights into the development of biopreservatives against foodborne pathogens.