Production of bacterial cellulose from enzymatic hydrolysate of kitchen waste by fermentation with kombucha

The industrialization and application of bacterial cellulose (BC) are restricted by high production cost and low productivity. In this paper, enzymatic hydrolysate of kitchen waste (KWH) was used as an alternative low-cost source to produce BC, aiming to facilitate its economic feasibility of industrial production. When KWH containing 13.11% total sugar and 1.27% total protein was used as medium of kombucha, BC yield was rapidly increased to 6.05 +/- 0.17 g L-1 at 7 days of fermentation. As the extra nutrients, adding 5% glucose and 0.5% ammonium sulfate would significantly decrease the BC yield, while 0.5% peptone could promote the production of BC. Furthermore, the optimal KWH medium was determined through the Box-Behnken design as diluting KWH with distilled water at ratio of 1:0.8, adding 0.6% peptone, and adjusting initial pH to 5.5. The BC yield of 7.21 +/- 0.25 g L-1 was obtained when kombucha was cultivated using this medium at 28 degrees C for 7 days, which was higher than many reported BC yield also taking organic waste as alternative source. Property characterization indicated that the obtained BC film had typical microfiber network; its Young's modulus and tensile strength values were 3314.7 +/- 193.5 MPa and 106.9 +/- 25.6 MPa, respectively, and the water holding capacity value was 98.8%. In conclusion, this paper realized the high efficient conversion of kitchen waste to high-performance BC film, which will provide a technical reference for decreasing the producing cost of BC and a strategy for realizing the green and high-value utilization of KW.