Xanthan Gum - Production Strains and Preservation in Fermentation Production

1. About Production Strains
Generally, xanthan gum production strain use pathogenic bacteria of black rot which belongs to cruciferous plant - xanthomonas bacteria and their variants, they can be got from the soil and plant pathogens that were screened isolated. The majority of xanthan gum production strains is xanthomonas campestris bacteria in China, usually use conventional methods of xanthan gum production strain.

There are not only conventional methods, but also by physical and chemical mutagenesis method to induce breeding of xanthan gum to improve the characteristics of its production Strains to produce gum, improve the product properties. For example, xanthan gum production strain can be screened by mutagenic treatment which could not produce pigment. If xanthomonas campestris dimethyl sulfate, lithium chloride or ultraviolet are compound treatment twice, rifampin, or bacitracin resistance plate screening, fermentation broth viscosity of mutants obtained increased by 30 % -70%, gum production increased by 20% -80%. The most ideal breeding method of high-quality xanthan gum’s producing bacteria is the use of genetic engineering, directed to transform and build new engineering bacteria, in order to achieve high quality, high yield, low-power purposes.

2. Regarding to Production strains preserved
In order to avoid degradation and variation of producing strain, we have to  try to limit the passage number of strains, avoid long-term preservation strain on agar slants, preferably be preserved by freeze-drying and cryopreservation preservation method.

The experimental result in that for long-term preservation of xanthan gum species preservation method could use mineral oil. The method is simple and easy to operate, survival rate of species is high, the longest retention time could be up to 5 to 6 years. five years later culture collection, the determination of fermentation liquid viscosity average is 81.7% of the original strain, gum production rate is of 87.6%, a variety of performance remained unchanged, the save results are satisfactory.