WYeast 1764 Pacman

 

Summary:

The yeast analyzed here has been "harvested" several times and was shipped during hot weather.

Average Viability: (49.02+55.74)/2=52.38%

Deviation in viability = 55.74-49.02=6.72%

Average Settled Slurry Cell Density: 575 million cells per ml

Deviation in Cell Density: 156 million cells per ml

Comments:

Viability is very low (This may have been due to heat exposure during shipping.)

Cell Density is low.  This is usual considering that there is very little non-yeast content.    The light packing may be characteristic of the strain or may be caused by the harvesting method.

No visible motile bacteria.

No pseudohyphae.  (Lack of pseudohyphae, as is the case here, indicates that the yeast was not grown in a stressful environment.)

Very little non-yeast material.

No noticeable flocculation.  (This is very unusual.  It could be a characteristic of this strain or it may have something to do with harvesting methods used for the slurry.  It also may explain the low cell density.)

Calculations:

Image 38_41

50 live

52 dead

Viability = 50/(50+52)= 49.02%

Image 38_26

34 live

27 dead

Viability = 34/(27+34)= 55.74%

dilution factor is 42ml/0.8ml=52.5

slide 1

816 cells.

1650x2088 pixels, 400px is one side of a 4nl box.

4.125x5.2x4=86.13 nl

816/86.13=9.47 cells per nl

9.47*52.5=497 million cells per ml

slide 2

1149 cells

1744x2120 pixels.

4.36*5.3*4=92.432nl

1149/92.432=12.43 cells per nl

653 million cells per ml

(497+653)/2=575 average cell density

653-497=156 deviation in cell density