RECOVERY OF STILBENOIDS
A cis- or trans-stilbenoid of the general formula (1) in which each of R 1 , R 2 , R 3 , R 4 and R 5 is hydrogen or hydroxy, or a glycosylated or oligomeric form thereof, such as resveratrol or pinosylvin is produced by cultivating a microorganism such as a genetically engineered yeast to produce said stilbenoid in a culture medium in solid form, and is separated by filtration or settling.
1 . A method for the production of a cis- or trans-stilbenoid of the general formula 1:
in which each of R 1 , R 2 , R 3 , R 4 and R 5 is hydrogen or hydroxy, or a glycosylated or oligomeric form thereof, comprising cultivating a micro-organism producing said stilbenoid in a culture medium, wherein said cultivation is performed so as to accumulate one or more said stilbenoids in said culture medium in solid form, and separating at least one said solid stilbenoid from the culture medium.
2 . The method as claimed in claim 1 , wherein said solid stilbenoid is separated from said culture medium by filtration or by settling.
3 . The method as claimed in claim 1 , wherein at least one said stilbenoid has an average particle size larger than cells of said micro-organism and is at least partially separated from said micro-organism cells present in said culture medium by separating solids in said culture medium according to their size.
4 . The method according to claim 3 , wherein the average particle size of said stilbenoid is at least double the average size of said cells.
5 . The method as claimed in claim 1 , wherein the concentration of at least one said stilbenoid in the culture medium prior to said separation is at least double the solubility limit of said stilbenoid in said culture medium.
6 . The method as claimed in claim 1 , wherein said cultivation is conducted at a first temperature and said culture medium is cooled from said first temperature to a lower second temperature prior to said separation of solid stilbenoid therefrom.
7 . The method as claimed in claim 1 , wherein following said cultivation, said culture medium is rested to produce an increase in the average particle size of stilbenoid solids therein.
8 . The method as claimed in claim 1 , wherein following said cultivation, said culture medium is acidified to produce lower the solubility of the stilbenoid therein.
9 . The method as claimed in claim 8 , wherein following said cultivation, the pH of said medium is lowered and/or the medium is cooled, a period of hours is allowed to pass, and thereafter solid stilbenoid is separated.
10 . The method as claimed in claim 1 , wherein the average particle size of stilbenoid solids in said medium is at least 10 μm.
11 . The method as claimed in claim 1 , wherein the cultivation is performed to produce a first said stilbenoid in solid form having a first average particle size and a second said stilbenoid in solid form having a second average particle size different from said first average particle size, and a separation or partial separation of said first and second stilbenoids is carried out by separating solids of different particle sizes from one another.