Production of bacterial cellulose using polysaccharide fermentation wastewater as inexpensive nutrient sources

Bacterial cellulose (BC) is a nanostructured material mainly produced by Gluconacetobacter. The excellent physicochemical and mechanical properties of BC have made it become regarded as a kind of highly functional biopolymer in the application fields of bio-medicine, cosmetics and food industry. Using low-cost carbon sources as raw materials could make BC production more cost-effective. In this study, the pullulan fermentation wastewater with high chemical oxygen demand (COD) value of 39040mg/L was used as substrate for BC production. After 10days of fermentation, a BC yield of 1.177g/L in wastewater was obtained, lower than that (1.757g/L) produced in Hestrin-Schramm (HS) media. During the fermentation process, 59.49% of monosaccharide coupling with 18.9% of COD in wastewater decreased. There were no differences in the functional groups and crystal patterns of the BC samples produced in wastewater and HS medium. However, more pores and loose three-dimensional networks were observed in the microstructure of BC samples produced in wastewater, resulting in lower crystallinity (56.23%) and Young's modulus (3984.29MPa) compared to that obtained from HS media. It indicated the nutrients composition of fermentation wastewater showed obvious effects on BC microstructure and mechanical properties. Our work demonstrated the possibility of using polysaccharide fermentation wastewater as inexpensive carbon source for BC production. Further study should be done in the improvements of the physical and chemical properties of BC sheets.