3.2. BC production
After hydrolysis, WBY hydrolysates were directly supplied to G. hansenii CGMCC 3917 as carbon and nutrient sources to produce BC without any extra nutrient added. In Fig. 2 it can be observed that the BC yields obtained using centrifuged WBY from pre-treatment 1and pre-treatment 3 were both higher than those from the WBY which were not centrifuged. This could be likely due to the fact that the uncentrifuged samples after these pre-treatments have a high sugar concentration (they showed the highest sugar yields) which could cause the inhibition of the BC production and reduce the supply of oxygen by the liquid medium. While in the centrifuged samples the reducing sugar concentration was decreased by diluting the supernatant with water, which could lead to a better concentration for BC production. In contrast, the centrifuged WBY from pre-treatment 2, pre-treatment 4 and the untreated WBY produced lower BC yields compared to those from the uncentrifuged WBY. Likely the cellulose production by G. hansenii CGMCC 3917 in this case was inhibited due to the low sugar concentration present in the centrifuged samples, which were further diluted from the already low sugar yields of WBY obtained from these pre-treatments.