Fig. 4

Evaluation of the contamination-controlling effects of BICCS based pH-rising strategy for ethanol photosynthetic production of Syn-HZ24. a Ethanol production of Syn-HZ24 cultivated in sterilized (red open squares), non-sterilized (blue triangles), and Pannonibacter phragmitetus inoculated BG11 culture medium bubbled with 5% CO₂ as main carbon source. Red crosses denoted the pH values during the cultivation process. b CFU dynamics of Synechocystis (open square) and Pannonibacter (closed circle) cultivated in BG11 culture medium bubbled with 5% CO₂–air steam without pH-rising strategy. c Ethanol production of Syn-HZ24 cultivated in sterilized (red open squares), non-sterilized (blue triangles), and Pannonibacter phragmitetus inoculated BG11 culture medium with BICCS-based pH-rising strategy. Red crosses denoted the pH values during the cultivation processes. pH values were allowed to increase to 11 physiologically and then constantly maintained at 11 with 180 mM NaHCO₃ and air stream. d CFU dynamics of Synechocystis (open square) and Pannonibacter (closed circle) cultivated in BG11 culture medium with the BICCS-based pH-rising strategy. pH values of the cultivation process were maintained in the range from 10 to 11