Production of bacterial cellulose by agitation culture systems

An economical mass production system of bacterial cellulose (BC) on agitated culture was constructed. We frst conducted screening of BC producers in agitated culture. A total of 2096 strains were isolated from natural sources and the best BC producing strain, BPR2001, was selected. According to the taxonomic examination, we concluded that the strain belongs to a new subspecies, Acetobacter xylinum subsp. sucrofermentans subsp. nov. Of the several organic nitrogen sources used to supplement the culture medium, corn steep liquor (CSL) was found to be the most suitable for BC production. A mutant strain derived from BPR2001, BPR3001E, resistant to an analogue of PABA, sulfaguanidine, showed increased cell growth and 40% higher BC productivity than BPR2001. A host-vector system for the BC producing Acetobacter strain was then developed using an indigenous plasmid, pAH4, detected in BPR2001. The complete nucleotide sequence of pAH4 was determined and the shuttle vector pSA19 was constructed by connecting pAH4 to pUC18. pSA 19 was found to be very stable and the system was suitable for introducihg genes into the BC producer in order to increase the yield of BC. Effective agitation culture systems essential for the BC ferementation with high yields were also developed. When the BC produced in this system was examined as a wet-end additive for papermaking processes, both the tensile strength and filler-retention of the resulting handsheets were found to be distinctly improved.