Help! Viscous bean extract! (oo-er).

Dr. David J. Meyer meyerdj at
Thu Nov 19 09:41:16 EST 1998

bmbthc at (Hedley Carr) wrote:

>Hi there,

>I am currently trying to sterilise an extract of bean (Phaseolus
>vulgaris) cotyledon tissue to allow its application to sterile plant
>growth media. The trouble is it's just too viscous to filter-sterilise.
>I've tried standard 0.2micron and 0.4micron syringe filters but they
>clog almost instantly. A glass fibre 'pre-filter' syringe filter also
>clogged instantly.

>I need the sterilisng method to be as non-destructive as possible as I
>am studying the effects of an as yet unidentified (but small) component
>of the extract for biological activity. Hence, autoclaving and UV
>treatment are out of the question.

I would try centrifuging the extract at 100,000 g for 1 hour prior to
filter sterilization if you are not already doing this. Then if your
factor is not active or present in this supernatant you have defined
it as something found in a very large complex or associated with

Good luck!

>I haven't worked with bean tissue before and so I don't really have much
>idea of what the filter-clogging contaminant is, though I suspect it is
>some mixture of soluble fibre/polysaccharides.

>Anybody have any ideas?


>Hedley Carr.
>School of Biochem. & Mol. Biol.,
>University of Leeds,

>PS. If replying via e-mail, delete 'REMOVE' from my address.

Dr. David J. Meyer
Quality Traits
Pioneer Hi-Bred International, Inc.

meyerdj at
7300 NW 62nd Ave.
Johnston, IA   50131-1004

Ph. 515/254-2639
FAX 515/254-2619
Email: meyerdj at

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