Cellulose Congo red culture base screening cellulose enzymes to produce bacteria.

asked:
I have done two batches of cellulose Congo red
culture
-based screening
strains
, after vaccination, found that the first batch can produce red hydrolysis ring, and the second batch can produce transparent ring. These two batches
the same
of the culture base, I would like to ask, what effect should be produced?
:
principle of screening strains using cellulose Congolese red culture base is:
1, Congolese red can be firmly combined with large molecule polysaccharides.
2, cellulose is a large molecule polysaccharid, and Congo red solid combination.
cellulose in the cellulase-degraded plate becomes a small molecular sugar, then The Congolese red cannot bind to the small molecular sugar and is washed away and presents a transparent circle.
4, in the usual cellulose Congolese red medium screening bacteria program, first with cellulose-containing flat culture bacteria, and so on after the bacteria grow out, the bacteria scraped away, and then added Congolese red dyeing 10-15 minutes, and then rinsed with NaCl 2-3 times, to produce transparent circles is the bacteria that can hydrolyte cellulose. Congo red can also be added directly to the plate, bacteria in the growth process will gradually form transparent circles, but the previous method is more sensitive.
so why is there a red hydrolysing ring, and the second batch can produce transparent rings? In fact, this cellulose-degrading transparent ring should be pale yellow, and if the molecular weight of polysaccharin changes, the degree of Congolese red binding will change, resulting in a change in color from crimson to pale yellow. This is why two batches of dyeing have different results.
.