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An improved, totally automated antibiotic bioassay machine
Author(s) -
Burns Donald A.,
Williams Paul R.,
Hansen Gary D.
Publication year - 1969
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260110522
Subject(s) - bioassay , incubation , chromatography , fermentation , filter paper , chemistry , food science , biology , biochemistry , genetics
Abstract A number of improvements have been made in a totally‐automated antibiotic bioassay machine previously described. The new machine accepts unmeasured, untreated, opaque suspensions of fermentation beers three times faster (120 samples per hour) and supplies printed potencies sooner (in just over two hours). Whereas the original machine employed a self‐cleaning filter and used disposable two milliliter beakers, this version involves a batch‐dialysis scheme for effecting sample purification, and provides for automated cleaning of incubation chambers. In operation, a measured, portion of thoroughly‐mixed fermentation beer is automatically diluted and transferred into one side of an incubation chamber, the two halves of which are separated by a dialysis membrane. The other half is filled with inoculated media. During the two hour incubation at 37°, dialyzable antibiotic limits growth of the inoculum in proportion to its concentration. After incubation, the turbidity of the inoculum is simultaneously read by an online computer and plotted on a strip chart recorded. The computer suplies printed potency values and sample identification on site, while the recording provides the operator with an analog record of turbidity. Fiber optics are employed in the turbidmetric readout, and an electric typewrite provides the printout.