Chemistry: molecular biology and microbiology – Micro-organism – tissue cell culture or enzyme using process... – Preparing sulfur-containing organic compound
Patent
1995-11-14
1998-03-24
Lankford, Jr., Leon B.
Chemistry: molecular biology and microbiology
Micro-organism, tissue cell culture or enzyme using process...
Preparing sulfur-containing organic compound
435136, 435157, 435170, C12P 1100, C12P 740, C12P 704, C12P 104
Patent
active
057311773
DESCRIPTION:
BRIEF SUMMARY
This application claims benefit of international application PCT/EP94/01640, filed May 16, 1994.
The invention concerns a process demethylating dimethyl-sulphonium compounds. More particularly the inventions concerns a process for microbiologically demethylating dimethylsulfonium compounds to the corresponding S-methyl-mercapto compounds, such as 3-dimethylsufonium propionate to S-methyl-3-mercaptopropionate.
Various S-methylmercapto compounds are either useful as flavour components themselves or as intermediates therefor. Thus, S-methyl-3-mercaptopropionate (hereinafter referred to as MMPA for convenience) may be converted into its alkyl esters which are used e.g. in various fruit flavours. Also, MMPA may be further demethylated to 3-mercaptopropionate (hereinafter referred to as MPA for convenience) the esters of which are also used as flavour components.
MMPA is known to be an intermediate in the-degradation of 3-dimethylsulfonium propionate (also known as dimethyl-.beta.-propiothetin, but hereinafter referred to as DMSP for convenience) in anoxic marine coastal sediments. A product of this degradation pathway is MPA and it was shown by R. P. Kiene and B. F. Taylor, Appl. Environ. Microbiol. 54:2208-2212, and Nature 332:148-150, that MMPA is converted to MPA at a rate similar to that of the conversion of DMSP to MMPA. MMPA and MPA are also intermediates in the metabolism of DMSP by certain aerobic bacteria, whereas other aerobic bacteria are known to degrade DMSP via an initial cleavage to acrylate and dimethyl sulfide (B. F. Taylor and D. C. Gilchrist, Appl. Environ. Microbiol. 57:3581-3584). Thus, although in theory DMSP might be the starting material for preparing MMPA, this so far appeared to be impossible due to the immediate further degradation to MPA. Moreover, although The DMSP - MMPA - MPA conversion was known to take place in coastal sediment, the microorganisms responsible for this degradation were unknown.
It is also known, as already indicated above, that DMSP can be cleaved to dimethylsulfide and acrylate and this process is known from many literature sources to take place in various marine organisms, especially algae. The process has been described in JP-A-63/222670 as a useful source of dimethylsulphide for flavouring purposes. This Japanese patent application also describes various useful sources of DMSP, including various marine organisms and especially algae. Finally it describes how DMSP may be isolated from these sources. However, it does not describe the conversion of DMSP in MMPA or MPA. It has now been found, however, that S-methylmercapto compounds and mercapto compounds can be prepared using a process which comprises the step of demethylating a dimethylsulfonium compound of general formula I to the corresponding S-methylmercapto compounds of general formula II, using a microorganism or alga which is capable of demethylating DMSP to MMPA, but which is incapable of further demethylating MMPA to MPA with the-same or comparable speed, or using an enzyme preparation derivable from such microorganism. ##STR2##
In these general formulae R denotes an alkyl radical derived from an alkane carboxylic acid or a derivative thereof. Examples of such radicals are: CH.sub.2 --CH.sub.2 --COOH (I is DMSP), CH.sub.2 --CH(NH.sub.2)--COOH (I is S-dimethyl-cystein), CH.sub.2 --CH.sub.2 --CH(NH.sub.2)--COOH (I is S-methyl-methionine) and CH.sub.2 --COOH (I is 2-dimethylsulphonium acetate, also known as dimethylthetin) and salts or esters of any of these. Such starting materials and various others for the demethylation according to the invention can be found in nature e.g. in various marine organisms and in brassica species and asparagus.
In the process the S-methylmercapto reaction product accumulates in the medium in which the microorganism is cultivated, respectively in the reaction medium in which the enzymatic reaction is carried out, and which contains the dimethylsulfonium compound. The reaction product can be isolated therefrom. The process is especially useful for converting DMSP into MMPA or
REFERENCES:
van der Maarel et al. 1993 Arch. Microbiol. vol. 160 pp. 411-412.
Heijthujsen et al. 1989. Arch. Microbiol. vol. 152 pp. 393-396.
Kiene et al. 1988. Appl. Environ. Microbiol. vol. 54 pp. 2208-2212.
Visscher et al. 1991. Appl. Envir. Microbiol. vol. 57, pp. 3237-3242.
Visscher et al. 1992. Mar. Ecol. Prog. Ser. vol. 189 (2-3) pp. 293-296.
Hansen Theo Adriaan
van der Maarel Marc Jos E. C.
Lankford , Jr. Leon B.
Quest International B.V.
Tate Christopher R.
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