Process for purifying target compounds from plant sources using ceramic filtration
The present invention describes a method for isolating a target compound from a plant, the method comprising obtaining a plant extract, passing such plant extract through a ceramic filter to obtain a permeate, and purifying the target compound from such permeate. This method, among other things, allows ultrafiltration of crude plant extracts, such as green juice homogenates.
1 . A method for isolating a target compound from a plant, the method comprising:
(a) homogenizing tissue of the plant to produce a green juice homogenate;
(b) passing the green juice homogenate from step (a) through a ceramic filter; and
(c) purifying the target compound from a permeate created in step (b).
2 . The method of claim 1 , wherein the ceramic filter has a pore size of equal to or less than 5 microns.
3 . The method of claim 2 , wherein the pore size is less than or equal to 1 micron.
4 . The method of claim 3 , wherein the pore size is less than or equal to 0.2 micron.
5 . The method of claim 4 , wherein the pore size is less than 0.1 micron.
6 . The method of claim 1 , wherein step (a) further comprises adjusting the pH and/or ionic content of the green juice homogenate such that the target compound is soluble.
7 . The method of claim 6 , wherein the pH is adjusted.
8 . The method of claim 6 , wherein the ionic strength is adjusted.
9 . The method of claim 6 , wherein the pH is neutral to acidic.
10 . The method of claim 9 , wherein the pH is adjusted to equal to or less than about 7.
11 . The method of claim 10 , wherein the pH is adjusted to equal to or less than about 5.2.
12 . The method of claim 1 , wherein step (a) further comprises heating the green juice homogenate to between about 45° C. to 65° C.
13 . The method of claim 1 , wherein step (c) comprises ultrafiltration.
14 . The method of claim 1 , wherein step (c) comprises chromatography, an affinity-based method of purification, salt precipitation, polyethylene glycol precipitation or crystallization.
15 . The method of claim 1 , wherein step (c) comprises subjecting the permeate to cation exchange chromatography.
16 . The method of claim 15 , wherein the cation exchange chromatography comprises a Sepharose SP column.
17 . The method of claim 15 , wherein step (c) further comprises subjecting an eluant from cation exchange chromatography to reversed phase chromatography.
18 . The method of claim 16 , wherein the reversed phase chromatography comprises a column selected from the group consisting of RPC 15 and RPC 30.
19 . The method of claim 1 , wherein step (b) further comprises washing one or more times a concentrate created by passing the green juice homogenate through the ceramic filter.
20 . The method of claim 1 , wherein the plant is infected with a viral vector.
21 . The method of claim 20 , wherein the viral vector is derived from tobacco mosaic virus.
22 . The method of claim 20 further comprising purifying the viral vector or a portion thereof from a concentrate produced in step (b).
23 . The method of claim 1 , wherein the target protein is expressed in the plant by a transgene.
24 . The method of claim 1 , wherein the target compound is a protein.
25 . The method of claim 24 , wherein the protein is aprotinin.
26 . The method of claim 24 , wherein the protein is an antiviral protein.
27 . The method of claim 24 , wherein the target protein is soluble.
28 . The method of claim 1 , wherein the target compound is selected from the group consisting of sugars, vitamins, alkaloids, flavors, and amino acids.
29 . The method of claim 1 , wherein in step (b) the ceramic filter comprises more than one ceramic filter arranged in a series.
30 . The method of claim 29 , wherein the more than one ceramic filter comprises two ceramic filters having pore sizes of 0.1 micron and 0.2 micron.
31 . A method for isolating a target protein from a plant, the method comprising:
(a) obtaining a plant extract;
(b) passing the plant extract from step (a) through a ceramic filter; and
(c) purifying the target compound from a permeate created in step (b).
32 . The method of claim 31 , wherein the plant extract is an interstitial fluid extract.
33 . The method of claim 31 , wherein the plant extract is a green juice homogenate.
34 . A method for purifying virus from a plant extract comprising passing the plant extract through a ceramic filter with a pore size of at least 0.5 micron.
35 . The method of claim 34 , wherein the pore size is at least 0.2 micron.
36 . The method of claim 35 , wherein the pore size is at least 0.1 micron.
37 . The method of claim 36 , wherein the virus is tobacco mosaic virus.