Fig. 4

a Field emission scanning electron microscopy (FE-SEM) of calcium carbonate precipitated by YS11 single culture and YS11 + AK13 coculture (×30,000 and ×5000 magnification). b FTIR analysis of precipitated calcium carbonate. c CLSM image of biofilm and calcium carbonate produced by YS11 single culture. d Crystal violet quantification of biofilm formation in single culture or YS11 + AK13 coculture. e Killing curve assay of YS11 alone, AK13 alone, and YS11 plus AK13 under pH 12