Enhanced cellulose production by ultraviolet (UV) irradiation and N-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutagenesis of an Acetobacter species isolate
Cellulose-producing bacteria were isolated from 14 bacterial cellulose (BC) factories in Thailand, and subjected to ultraviolet (UV) irradiation and/or N-methyl-N'-nitro-N-nitrosoguanidine (NTG) mutagenesis for strain improvement. BC yields of the NTG mutant NU4-NTG30-51 were 54.68% higher than that of the reference strain Acetobacter xylinum ATCC 10245 and 43.69% higher than that of the parent strain NU4 (P < 0.01). BC yields of the UV mutant NU4-UV40-07 were 50.59% higher than that of A. xylinum and 39.60% higher than that of NU4. Glucose consumption of these mutants was also higher than that of NU4. However, crystallinity of cellulose produced by NU4-NTG30-51 was higher than that produced by NU4-UV40-07. Combining UV irradiation and NTG did not result in BC yields higher than those of the mutants generated with a single mutagen. The mutant strains were then tested for reversion. Our results demonstrate that the BC yields of these mutants remained higher than that of the reference strain A. xylinum ATCC10245, and did not revert to the same level as the parent strain. The isolate NU4 and the two mutants were identified as Acetobacter species.
Key words: Acetobacter xylinum, bacterial cellulose, strain improvement, UV irradiation (UV), N-methyl-N'-nitro-N-nitrosoguanidine (NTG).