Author(s): Ivanova V, Yankov D, Kabaivanova L, Pashkoulov D
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Abstract Thermostable alpha-amylase with temperature optimum at 80 degrees C, molecular mass 58 kDa and pI point 6.9 was purified from a catabolite resistant Bacillus licheniformis strain. The enzyme was sensitive to inhibition by metal ions and N-bromosuccinimide. The partition behaviour of this enzyme in aqueous two-phase systems (ATPS) of the polymer-polymer-water type was investigated and some effects of type, molecular weight and concentration of phase components were studied. Up to 100\% retention in the bottom phase of polyethylene glycol 10,000-20,000/dextran 200 system was reached. Best partition conditions were obtained in PEG 10,000-20,000/polyvinyl alcohol 200 systems, where the partition coefficient K increased 750 times to 7.5. Simultaneous production and purification of alpha-amylase and serine proteinase in PEG-polymer-water ATPS were examined. In the system PEG 6,000/ficoll, up to 90\% of the amylase was retained in the bottom phase, whereas about 95\% of the total protein (K = 22.8) and 60-75\% of the proteinase were in the top phase. Similar separation of the enzymes from laboratory supernatant was obtained in system PEG/Na2SO4.
This article was published in Microbiol Res
and referenced in Journal of Biodiversity, Bioprospecting and Development