In an attempt to obtain bacterial cellulose (BC) with improved rehydration ability, Tween 80, urea, fluorescent brightener, hydroxypropylmethyl cellulose (HPMC) and carboxymethyl cellulose (CMC) were introduced into BC fermentation medium. Measurements of the mechanical strength of the resulting BCs (TBC, UBC, FBC, HBC and CBC) showed a decline except for UBC. SEM images showed that, although the cellulose bundle widths of FBC, HBC and CBC increase, the cellulose network void in FBC grew, while those in HBC and CBC shrank. X-ray diffraction and FT-IR analysis demonstrated that the addition of HPMC and CMC reduced the degree of crystallinity in their corresponding MBCs from 70.54% to 52.23% and 45.38%, respectively. HBC and CBC also exhibited the highest rehydration ability among all MBCs as well as the lowest crystallinity. The in situ modification with HPMC and CMC during fermentation can effectively improve rehydration ability of BC by altering its network structure. (C) 2010 Elsevier Ltd. All rights reserved.