Abstract Immobilized water-insoluble biocatalysts in particulate form comprise living cells, particularly yeast, dispersed in a cross-linked gelling agent. An enzyme, particularly amyloglucosidase, may be co-immobilized in the particles. These particles are prepared by suspending the living cells in an aqueous solution of a gelling agent, dispersing this suspension in a water immiscible organic liquid to form a suspension in the liquid of aqueous particles comprising the living cells and gelling agent, gelling the gel and cross-linking the gelling agent. It is found that when living cells such as microbial cells and especially yeast are immobilized in this way, that surprisingly, not only is their viability retained, but the ability of yeast cells to produce ethanol under continuous fermentation conditions is significantly improved. Specific strains of Saccharomyces cerevisiae, suitable for immobilization in this way, are described.
A method of preparing an immobilized water-soluble biocatalyst comprising living cells in particulate form consisting essentially of the steps of: (a) suspending the living cells in an aqueous solution of a gelling agent, (b) combining the mixture so obtained with an organic liquid poorly miscible or immiscible in water to form a suspension in the organic liquid of aqueous particles comprising the living cells and gelling agent, (c) treating the suspension to gel the gelling agent in the particles, (d) treating the particles obtained in step (c) with a bi- or polyfunctional cross-linking agent to covalently crosslink the gelling agent in the particles, and (e) removing at least part of the water from the particles obtained in step (d) to obtain particles with a dry matter content of at least 15% by weight.
Claim 2
Independent Claim
133 words
A method of preparing an immobilized water-soluble biocatalyst comprising living cells in particulate form consisting essentially of the steps of: (a) suspending the living cells in an aqueous solution of a gelling agent, (b) combining the mixture so obtained with an organic liquid poorly miscible or immiscible in water to form a suspension in the organic liquid of aqueous particles comprising the living cells and gelling agent, (c) treating the suspension to gel the gelling agent in the particles, (d) treating the particles obtained in step (c) with a bi- or polyfunctional cross-linking agent to covalently crosslink the gelling agent in the particles, and (e) removing at least part of the water from the particles obtained in step (d) to obtain particles with a dry matter content of at least 15% by weight.
Claim 3
Dependent Claim
36 words
A method according to claim 1 wherein an enzyme, compatible with the living cells and gelling agent, is introduced into the suspension of step (a) and/or is introduced into the gelling suspension during cross-linking step (d).
Claim 4
Dependent Claim
18 words
The method of claim 1 wherein water is removed from the particles in Step (e) by osmotic shrinking.
Claim 5
Dependent Claim
20 words
The method of claim 1 wherein water is removed from the particles in Step (e) by a fluidized bed drier.
Claim 6
Dependent Claim
16 words
The method of claim 3 wherein the particles are further dried by a fluidized bed drier.