Acid Hydrolysis of Konjak Tuber as a Cheap Carbon Source for Bacterial Cellulose Production

Bacterial cellulose (BC) is a new kind of natural polymer for biomedicine based on its unique properties. For the economic production of BC, the exploitation of cheap carbon source is one of the key factors. Konjak tuber is from a kind of herbage Amorphophallus rivieri Durieu, which has a long history, abundant resource and extensive distribution in China. In this study dry konjak tuber was chosen due to its cheapness, rich resource and convenient storage. It could be hydrolyzed to reducing sugar (glucose-mannose mixture) by H2SO4. The optimal acid hydrolytic conditions of konjak tuber for bacterial cellulose production were optimized. Firstly the optimal time, temperature, H2SO4 concentration and solid-liquid ratio for acid hydrolysis of dry konjak tuber were obtained by single-factor experiments. The optimum single-factor conditions were as follows: 1 mol/L H2SO4, solid-liquid ratio of 1 5, hydrolytic temperature of 110 degrees C, hydrolytic time of 0. 5 h. Secondly, based on the results of single-factor experiments, response, surface methodology was used to optimize the hydrolytic conditions. The optimal conditions obtained from response surface methodology were that reducing sugar yield of 66.8% could be reached at 115 degrees C for 40 min with H2SO4 of 0. 5 mol/L and solid-liquid ratio of 1 : 7. Finally the acid hydrolysates would be detoxified and used as carbon source for the production of BC. Acid hydrolysates of konjak tuber behaved much better in the production of BC compared with other carbon sources, such as sucrose, glucose, mannose and glucose-mannose,mixture.