Apparatus, methods and compositions for biotechnical separations

Abstract

RNA, preferably messenger RNA, is purified by use of selective precipitation, preferably by addition of compaction agents. Also included is a scaleable method for the liquid-phase separation of DNA from RNA. RNA may also be recovered by fractional precipitation according to the invention. We have discovered that specific classes of compounds are unexpectedly potent in causing selective precipitation of DNA away from RNA, at low concentrations and in the presence of relatively elevated ionic strength. Modification of the selective removal of DNA can also remove both RNA and DNA, leaving behind a mixture which is advantageous for the further purification of, e.g., proteins. Additional aspects of the invention include mini-preps, preferably of RNA or of plasmid and chromosomal DNA to obtain sequenceable and restriction digestible DNA in high yields in multiple simultaneous procedures. Still further aspects disclose enhanced stripping of the compaction agent by a stripping method comprising high salt addition and pH shift, and combinations of these techniques. RNA Abstract Additionally, a new approach to the isolation of RNA from bacterial lysates employs selective precipitation by compaction agents. The above techniques can be enhanced by use of phase transfer catalysts (PTCs), most preferably selected polyamines of U.S. Pat. No. 6,617,108 polyamines which are quaternary compounds. (The use of PTCs in biotechnical processes is not evident in the literature, see e.g. www./ptorganics.com as of 27 Jan. 2005.)

Dependencies are inferred from the claim text.