Tate & Lyle Public Limited Company

Kelco Biospecialties Limited

Andrew J Hacking

Jonathan S Dordick

Riaz A Khan

Peter S Cheetham

Elner B Rathbone

Khizar S Mufti

Trevor Rodney Jarman

Stephen Bornemann

John M Cassells

Clive L Combes

Jonathan S Dordik

Sucrose or derivatives thereof such as esters are acylated at the 4'- and/or the 6- position by reaction with a donor acyl ester, e.g. a reactive ester of an alkanoic acid or benzoic acid, in the presence of lipase. Sucrose 6,4' so produced can be chlorinated and deacylated to produce the sweetener sucralose.

Sucrose 6,4'-dicarboxylic esters

Sucrose derivatives partially acylated in each ring can be obtained by treating a fully or partially acylated sucrose derivative with an enzyme having sucrose esterase activity capable of removing at least one acyl group from each ring, generally comprising or being a component of a lipase, esterase, amylase, .alpha.-galactosidase or protease preparation, the enzyme treatment being effected in an aqueous system. Sucralose can be obtained by using this method to obtain a sucrose 2,3,6,3',4'-penta ester which can then be chlorinated and de-esterfied. Some of the penta acetates, tetraacetates and mixed acetates/butyrates are new compounds.

Preparation of acylated sucrose derivatives

Sucrose or derivatives thereof such as esters are acylated at the 4'- and/or the 6-position by reaction with a donor acyl ester, e.g. a reactive ester of an alkanoic acid or benzoic acid, in the presence of lipase. Sucrose 6,4'-diesters so produced can be chlorinated and deacylated to produce the sweetener sucralose.

Selective acrylation of sugars

The novel chlorinated sugar O-.alpha.-D-6-chloro-6-deoxygalactopyranosyl-(1.fwdarw.6)-.alpha.-D-4-chlo ro-4-deoxygalactopyranosyl-(1.fwdarw.2)-.beta.-D-1, 6-dichloro-1, 6-dideoxyfructofuranoside (TCR) can be used to prepare sucralose by incubating the TCR in solution in the presence of an enzyme serving to remove the 6-chloro-6-deoxygalactosyl moiety from the 6-position, especially an enzyme derived from a strain of Mortierella vinacea, Circinella muscae or Aspergillus niger. TCR is prepared by treating raffinose with thionyl chloride in the presence of triphenylphosphine oxide.

Tetrachlororaffinose and its use in the preparation of sucralose

A process for preparing a fructoside, especially a fructosyl disaccharide, comprises reacting a fructosyl saccharide such as sucrose or raffinose with an alcohol or aldose in the presence of a fructosyl-transferase, especially one derived from B. subtilis NCIB 11811, 11872 or 11873. In particular, aldose is a compound of the formula ##STR1## in which A represents a hydrogen atom or the group CH.sub.2 X, where X represents a hydrogen atom or an alkoxy group, and the fructosyl disaccharide so formed is halogenated to provide a halosucrose or halogalactosucrose sweetener.

Process for the preparation of fructosyl disaccharides

A process for producing polysaccharide consisting of a partially acetylated variable block copolymer of D-mannuronic and L-guluronic acid residues comprises growing a biologically pure culture of a Pseudomonas mendocina microorganism selected from the group consisting of NCIB 11687, 11688, and 11689 in an aqueous nutrient medium by submerged aerobic fermentation of an assimilable carbon source and recovering the polysaccharide. Biologically pure cultures of the organisms are another feature of the invention.

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Mortimer, United Kingdom

Andrew J Hacking