Biotransformation of fermented black tea into bacterial nanocellulose via symbiotic interplay of microorganisms

Bacterial nanocellulose (BNC), a natural origin biopolymer with multi-dimensional applications has captured a great deal of attention owing to its implausible properties. However, low yield of BNC accompanied with high production cost is challenging its usage in various technological applications. In this study, BNC production has been reported utilizing fermented black tea broth brewed from fresh tea leaves (FBTB_F) as well as from used tea leaves (FBTB_U) as a cost-effective and high-quality BNC yielding medium. The symbiotic combination of bacteria and yeasts (SCOBY) was exploited here to bring fermentation in tea broth. The production yields on dry weight basis were 13.3 g L^-1 in FBTB_F and 12.8 g L^-1 in FBTB_U, obtained with 60 g L^-1 of glucose in 20 days. The conversion yields of 0.32 and 0.31 g BNC/g sugar were obtained with both the tea broths. The study of produced pellicle using ATR-FTIR, FE-SEM and XRD confirmed its structural, morphological and chemical nature similar to that of BNC. Thus, fermented black tea broth appears to be a potential medium for BNC production. The use of fermented tea broth for the industrial scale production of BNC might significantly reduce its production cost.