Objective The study aims to improve the utilization rate of waste Xinhui citrus flesh and explore the technical feasibility of producing bacterial cellulose (BC).

Method Taking Xinhui citrus juice as raw material and Kombucha as fermentation strain, the study investigated the effects of such factors as enzymatic pretreatment, citric acid addition, fermentation time and pH on the production rate of BC. Meanwhile, the study also explored the water content and rehydration rate of BC membrane, and the characteristics of infrared absorption spectrum, X-ray diffraction and scanning electron microscopy.

Result The average values of Brix and pH of fresh citrus juice were 10.9% and 3.9, respectively. The results of single factor test showed that the production rate of BC failed to be improved by adding citric acid or adopting enzymatic pretreatment. The highest BC production rate could be obtained by using original citrus juice as raw material and adjusting pH to 6.0 for 15 days. Besides, the fiber diameter of BC membrane was between 80 nm and 400 nm, its crystallinity was above 80%, and it could be used to produce biological fiber material with good mechanical properties. Enzymatic pretreatmen had a great impact on the microstructure of BC membrane. The BC membrane produced by original citrus juice was mainly composed of fine fibers. However, under the influence of enzymatic pretreatment, the microstructures of BC membrane was spherical, square or in a composite state of prismatic fiber and fine fiber.

Conclusion BC produced from Xinhui citrus juice showed good rehydration and high crystallinity, and the maximum production rate reached 2.25 g/L in single factor test. Therefore, Xinhui citrus juice can be used as raw material for bacterial cellulose production.