Effects of monosaccharides and protein in extracellular polymeric substances of Klebsiella aerogenes on crystalline forms of CaCO3 crystals

A strain of Klebsiella aerogenes ( K. aerogenes ) capable of decomposing calcium acetate for CaCO 3 biomineralization was screened, and the optimum conditions for producing the maximum mass of CaCO 3 crystals induced by Klebsiella aerogenes were found to be 0.25 mol/L calcium acetate, 4% inoculum level, and pH 7. Following that, the monosaccharides and proteins contained in the extracellular polymeric substances (EPS) of Klebsiella aerogenes were identified. The effects of additional identified monosaccharide and proteins on the crystalline form conversion of CaCO 3 crystals were investigated, and the additional monosaccharides were found to promote the crystalline form conversion of CaCO 3 crystals from vaterite to calcite. Specifically, adding 1.00 g/L glucuronic acid was observed to enhance the conversion of crystalline phases of CaCO 3 crystals to calcite completely after 5 d. Meanwhile, additional catalase was observed to contribute to the regular morphology of CaCO 3 crystals without affecting their crystalline phases. The results indicate that the additional glucuronic acid influences the crystalline forms of CaCO 3 crystals significantly.