Microencapsulation of yeast cells and their use as a biocatalyst in organic solvents

Abstract

Stable, semipermeable polyamide microcapsules were prepared by interfacial polymerization from a mixture of 1,6‐hexanediamine and poly(allylamine) crosslinked with di‐acid chlorides and were used to encapsulate baker's yeast. The size and distribution of cells within the capsules were investigated by a combination of laser confocal, electron scanning, and transmission electron microscopy. The encapsulated cells were studied as a biocatalyst for the model reduction of 1‐phenyl‐1,2‐propanedione to 2‐hydroxy‐1‐phenyl‐1‐propanone in a number of organic solvents. The polymerization conditions were extensively investigated and were found to greatly influence the product yield. Microencapsulated yeast cells, prepared under optimized conditions, carried out the reduction more efficiently than free cells as well as those immobilized in alginate and κ‐carrageenan beads. The developed methodology should be broadly applicable to other biotransformations of interest. © 1996 John Wiley & Sons, Inc.

Microparticles for cell encapsulation and colonic delivery produced by membrane emulsification

“…The increase in productivity is a consequence of the continuous operations practicable with encapsulated cells [11], increased cell density, facilitated cell recovery and re-use, enhanced yeast stability, increased yeast tolerance to ethanol and acetic acid, increased fermentation time, protection from harsh environments, reduced contamination [2,11]. Encapsulated yeast in alginate and carregeean beads are also reported as biocatalysts in organic solvents for complex reduction reactions [12]. There are reports [13] of the use of immobilized yeast in a polyacrylamide hydrogel for the production of L-phenylacetyl carbinol; an intermediate in the synthesis of L-ephedrine (used as an antiasthmatic and decongestant).…”

“…Eudragit coated microparticles were produced for the colonic release of therapeutics [16,18] or proteins [19], but it has not yet been applied for the coating of encapsulated cells. A variety of materials have been tested for the encapsulation of living cells; alginate [4,6,8,12,15,[20][21][22][23] is the most common and versatile, chitosan [9,23], gelatin [22,24], cellulose [23,25], agarose [23,26], dextran [1], carrageenan [9,12,27], poly(lactide-co-glycolide) (PLGA) [1,23], Poly (Ethylene Glycol) [23,28] all have been used individually, and in blends [1,27]. Chitosan is a proven biocompatible natural polymer produced from natural sources (crustacean shells, fungi, and insects), which has been widely used for cell encapsulation and other pharmaceutical purposes [23,29].…”

“…Many techniques for cell encapsulation have been reported, including interfacial polymerization [12] and solvent evaporation [7], sol-gel process [35], photolithography [28], ionic crosslinking [27]. In some cases, these techniques involve the prior formation of polymeric droplets in an oil-organic phase.…”

Evaluation of the catalytic activity of lipases immobilized on chrysotile for esterification

“…On the other hand, biocatalysis in nonaqueous media has emerged as a powerful tool for the production of fine chemicals, pharmaceuticals and food ingredients. Advantages commonly associated with the use of organic solvents as reaction media include improved solubility and chemical sta-bility of the organic substrates and facile product recovery (Green et al 1996).…”

Alginate Coating of Xenopus laevis Embryos

“…The major categories of entrapment have been reviewed (Cheetham, 1980; Bucke, 1983; Mattiasson, 1983; Nussinovitch et al, 1994; Jen et al, 1996; Nussinovitch, 1997). They include some commonly used, single‐step entrapment methods, such as the simple gelation of macromolecules by lowering or raising temperatures using hydrocolloids such as agar (Brodelius and Nilsson, 1980; Wiksstorm et al, 1982; Banerjee et al, 1982; Dobreva et al, 1996), agarose (Khachatourians et al, 1982; Wiksstrome et al, 1982), κ‐carrageenan (Chibata, 1981; Wang and Hettwer, 1982; Krouwel et al, 1982; Kim et al, 1982; Brodelius and Nilsson, 1980; Deriso et al, 1996; Walsh et al, 1996; Green et al, 1996), chitosan (Vorlop and Klein, 1981; Kluge et al, 1982; Stocklein et al, 1983; Deriso et al, 1996), gelatin, and egg whites (Deriso et al, 1996), among others. These preparations regularly suffer from low mechanical strength and possible heat damage.…”