IR-spectroscopic studies of Zymomonas mobilis and levan precipitate

The mid-infrared (mid-IR) absorption spectra of Zymomonas mobilis 113 "S" bacterial biomass grown in sucrose or glucose medium, and levan precipitate in the fingerprint region were studied. IR-qualitative and quantitative analyses were carried out. The principal component concentration changes in Z. mobilis biomass at different growth phases showed that protein concentration was higher in case of glucose-based medium, but the total carbohydrate concentration was higher if grown in sucrose-based medium. Low concentration of intracellular carbohydrates was a characteristic parameter of levan-producing Z. mobilis cells. It was shown that during 2-month storage of Z. mobilis inoculum in sucrose medium at 4°C the content of nucleic acids decreased, but other cell macromolecular component content did not change significantly. The levan precipitate IR-spectra in the 800-3400cm^-1 region indicated fructans as the main component, with negligible amounts of other carbohydrates. Qualitative analysis of IR-absorption spectra showed the presence of some amino acids in the precipitate. Thereby, the mid-IR-spectra proved the extent of purity of the obtained preparation.