Coproduction of bacterial cellulose and pear vinegar by fermentation of pear peel and pomace

Bacterial cellulose (BC)-derived materials are given significant attention due to their porous fibrous texture, high crystallinity and extraordinary physico-mechanical properties. The main reason for the restricted use of BC is its high production cost. To reduce the production cost, the suitability of pear residue for the production of BC and pear vinegar was investigated. Komagataeibacter rhaeticus and Komagataeibacter intermedius with high fermentation ability screened from the surface of vinegar film of millet fermentation were used to produce BC and pear vinegar simultaneously. Through response surface optimization, the maximum yield of BC from pear residue medium was 10.94 ± 0.42 g/L, which was higher than the synthesis medium generally used for Acetobacter strains. When pear residue medium was incubated at 30 °C for 7 days, the contents of total acid and soluble solids were greater than 0.3 g/100 mL and 3%, respectively, which met the standard requirements for fruit vinegar. The flavour components of pear vinegar were determined using gas chromatography–mass spectrometry. The pear vinegar showed similar flavour characteristics to conventional fruit vinegar. This research not only solved the utilization of agricultural resources but also avoided the discharge of waste liquid when producing BC. In addition, a more environmentally friendly and less expensive way to produce BC and pear vinegar was achieved.