Ashley Lovering (1), Jack Saad (1), Rick Shimkus (1); (1) Micromeritics Instrument Corporation, Norcross, GA, U.S.A.
Yeast cell health and reproduction rates are commonly characterized
using electric sensing zone (ESZ) technology, which is based on the
Coulter principle. This technique involves two cells of electrolyte
solution separated by an insulating barrier through which there is a
cylindrical orifice. The reservoirs have opposite electrical charges,
causing an electrical current to flow through the orifice channel, while
a pumping mechanism also causes the electrolyte to flow through the
same orifice channel. As electrolyte is flowing, yeast cells present in
the electrolyte will pass through the orifice displacing, electrolyte
and creating an resistance in the electrical current. The size of the
resistance is proportional to the volume of the yeast cell, and the
number of times a resistance appears correlates to yeast cell count.
Choosing the appropriate orifice size for the yeast cells being
characterized is vital to collecting accurate data. Each orifice size
has a specific size detection range. Using varying extreme size
differences in orifices that have overlapping size ranges to
characterize common yeast cells used in beer brewing, size and count
data are compared and contrasted.
Ashley Lovering obtained her ACS-certified B.S. degree in
chemistry, with a business concentration, from the Georgia Institute of
Technology. As an undergraduate student, she worked as a laboratory
technician in the metal energy and electroplating labs at Delta
Airlines, where her responsibilities included analyzing plasma spray
samples and maintaining electroplating tanks. Ashley joined
Micromeritics Instrument Corporation in 2014 as a lab analyst with their
contract analytical laboratory, Micromeritics Analytical Services. She
specializes in a variety of material characterization techniques,
including particle size distribution by electro-zone sensing, surface
area by gas adsorption, particle shape using dynamic image analysis, and
density by gas displacement.