Express Method for Redox Potential and pH Measuring in Microbial Cultures

The new modification of potentiometric pH and Eh measuring was developed. The essence of the method is to measure pH and Eh in compact hermetic redox cell. This modification provides reliable and fast pH and Eh measuring with minimum expense of culture liquid (1 cm3 for each measuring). The application of the developed modification in microbiology was shown on the example of bacterial culture Kocuria carniphila isolated from Negev desert soil (Israel). Dynamics of the Eh changing in the growing culture allows establishing the influence of the carbon and energy sources concentration on the microbial growth, the rate of oxygen consumption and character of microbial interaction with toxic compounds. Copiotriphic conditions (800 mg/l C) were shown to be optimal for K. carniphila. It was shown that K. carniphila was resistant to 200 ppm of Cu2+, nevertheless it did not extract Cu2+ out of liquid medium.