Development of a bottle-free multipurpose incubator for generating various bacterial culture conditions

The purpose of this study was to develop a multipurpose incubator, without the gas cylinders (bottles) which are required for H2 and CO2 supplementation. In our bottle-free multipurpose incubator, the H2 and CO2 were generated by chemical reactions induced within the chamber. The reaction between sodium borohydride and acetic acid at a molar ratio of 1:1 was used to generate H2, according to the following formula: 4NaBH4 + 2CH3COOH + 7H2O --> 2CH3COONa + Na2B4(O7) + 16H2, whereas the other reaction, citric acid and sodium bicarbonate at a 1:1 molar ratio, was used to generate CO2, according to the following formula: C6H8(O7) + 3NaHCO3 --> Na3(C6H5(O7)) + 3H2O + 3CO2. Five species of obligate anaerobic bacteria, one strain of capnophilic bacterium, and one strain of microaerophilic bacterium were successfully cultured in the presence of their respective suitable conditions, all of which were successfully generated by our bottle-free multipurpose incubator. We conclude that, due to its greater safety, versatility, and significantly lower operating costs, this bottle-free multipurpose incubator can be used for the production of fastidious bacterial cultures, and constitutes a favorable step above existing anaerobic incubators.