Optimization of preparative nonlinear chromatography was carried out for
the first time for a biomolecule mixture. Conventional wisdom on optimization,
which roots from analytical chromatography, dictates optimizing resolution in an
analytical column and obtaining similar separation in a large column for isolation.
Such a method of optimization significantly under uses the capacity of the column
and consumes large quantities of mobile phase. Hence, in preparative
chromatography, the objective function is productivity, a measure of compromise
between the amount of feed that can be loaded on to the column and time. Here,
we report results from optimization studies carried out on a closely related binary
peptide mixture on an analytical reversed-phase column. The goal is to optimize
productivity under various chromatographic modes nonlinear isocratic elution,
gradient elution, stepwise elution and displacement chromatography. In each
mode, feed mixtures at highest possible concentration (limited by solubility), for
increasing feed volumes was used. Productivity was monitored for increasing feed
volumes, and loading was stopped as it went through a maximum. However, in
some cases, solubility limitations from one of the feed components prevented
further increase in loading. Even with this constraint, high productivities
(5-10 g product/L stationary phase-h) were achieved. Separate experiments
were carried out to measure the adsorption isotherms of these peptides over the
range permitted by solubility.
Separations under nonlinear chromatographic conditions were applied to
isolate commercially significant two microcystins (microcystin LR and microcystin
LA) from a cyanobacterial process waste. Milligram-level loading of microcystins
was obtained on a solid-phase extraction cartridge packed with 0.5 g of C������
stationary phase. The separations were first carried out on an analytical column
and then scaled-up to a preparative column.
We also report simple and economical process to purify phycocyanins and
allophycocyanins from a cyanobactenal process waste stream for two kinds of
applications food colorant and biomedical marker. A detailed design for the large-scale
production of biliproteins for both applications is also presented. Economic
evaluation of the process resulted in comparable costs with the current market price
for food-grade product and substantially lower cost for the biomedical grade
product. / Graduation date: 2001
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32633 |
| Date | 14 December 2000 |
| Creators | Ramanan, Sundar |
| Contributors | Velayudhan, Ajoy K. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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