SELECTIVE PROCESS FOR PREPARING SULFOXIDES BY ENZYMATIC CATALYSIS

1 . A process for preparing a sulfoxide, comprising:

a) preparing a composition M comprising:

a sulfide;

an enzyme E catalyzing oxidation of said sulfide to sulfoxide;

optionally at least one cofactor C of said enzyme E; and

an oxidant;

b) carrying out the enzymatic oxidation reaction of the sulfide to sulfoxide;

c) recovering the sulfoxide obtained in step b); and

d) optionally isolating and/or optionally purifying the sulfoxide recovered in step c);

wherein said sulfide is not entirely consumed during step b) of carrying out the enzymatic reaction.

2 . The process as claimed in claim 1 , wherein said enzyme E is an oxidoreductase.

3 . The process as claimed in claim 1 , wherein said enzyme E is a Baeyer-Villiger monooxygenase (BVMO).

4 . The process as claimed in claim 1 , wherein said sulfide is of the following general formula:

R 1 —S—R 2   (I)

wherein:

R 1 and R 2 may be identical or different and are selected, independently of one another, from the group consisting of:

(C 1 -C 20 )alkyl, (C 2 -C 20 )alkenyl, (C 2 -C 20 )alkynyl, (C 3 -C 10 )cycloalkyl and (C 6 -C 10 )aryl or

R 1 and R 2 form, together with the sulfur atom to which they are attached, a heterocycloalkane or a heteroarene;

where said alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heterocycloalkane and heteroarene groups are optionally substituted by one or more substituents;

where said alkyl, alkenyl, alkynyl, cycloalkyl and aryl groups optionally comprise one or more heteroatoms.

5 . The process as claimed in claim 4 , wherein the radicals R 1 and R 2 of said sulfide are identical.

6 . The process as claimed in claim 1 , wherein said sulfide is selected from dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dioctyl sulfide, didodecyl sulfide and tetrahydrothiophene.

7 . The process as claimed in claim 1 , wherein the ratio [sulfide] (in mmol/L)/[cells] (in g cdw ·L −1 ) is between 0.01 and 10 mmol/g cdw .

8 . The process as claimed in claim 1 , wherein the oxidant is selected from the group consisting of air, oxygen-depleted air, oxygen-enriched air, pure oxygen and hydrogen peroxide.

9 . The process as claimed in claim 1 , wherein the cofactor C is selected from nicotine cofactors and flavin cofactors.

10 . The process as claimed in claim 1 , wherein the enzyme E is cyclohexanone monooxygenase and the cofactor C is NADP and optionally FAD.

11 . A composition comprising:

a symmetrical sulfide;

an oxidoreductase enzyme catalyzing oxidation of said symmetrical sulfide to symmetrical sulfoxide;

optionally at least one cofactor C of said enzyme E; and

optionally an oxidant.

12 . The composition as claimed in claim 11 , wherein the sulfide (I) is selected from dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dioctyl sulfide, didodecyl sulfide and tetrahydrothiophene.

13 . A method for oxidizing a symmetrical sulfide to symmetrical sulfoxide, the method comprising reacting the sulfide with an oxidoreductase enzyme.