Candida method

Espinel-Ingroff et al. [97] described a radial diffusion bioassay method for miconazole, which employs Candida stellatoidea as the indicator organism. Results from... 

The one-pot dynamic kinetic resolution (DKR) of ( )-l-phenylethanol lipase esterification in the presence of zeolite beta followed by saponification leads to (R)-l phenylethanol in 70 % isolated yield at a multi-gram scale. The DKR consists of two parallel reactions kinetic resolution by transesterification with an immobilized biocatalyst (lipase B from Candida antarctica) and in situ racemization over a zeolite beta (Si/Al = 150). With vinyl octanoate as the acyl donor, the desired ester of (R)-l-phenylethanol was obtained with a yield of 80 % and an ee of 98 %. The chiral secondary alcohol can be regenerated from the ester without loss of optical purity. The advantages of this method are that it uses a single liquid phase and both catalysts are solids which can be easily removed by filtration. This makes the method suitable for scale-up. The examples given here describe the multi-gram synthesis of (R)-l-phenylethyl octanoate and the hydrolysis of the ester to obtain pure (R)-l-phenylethanol. 

The dynamic behavior of the cell metabolism initiated by different external effects (addition of substrates or inhibiting reagents) can be followed via this instantaneous method. These effects can be used to control the overall process and optimize the bioprocess. Meyer and Beyeler [50] developed a control system for a continuous yeast cultivation process. Here the increase up to the optimal dilution rate was controlled via fluorescence monitoring. The dilution rate was only increased when no negative effect on the metabolic state of the cells was observed. During the cultivation of Candida utilis the fluorescence signal was used for the addition of substrate ethanol. The addition was started when... 

Abstract A simple, accessible and cost effective method of crystallographic identification of microorganisms has been developed. It allows rapid and snfficiently reliable identification of many clinically significant pathogens based on their crystallogenic properties. The nse of the crystallographic method snbstantially accelerated and simplified the identification of Candida spp. when compared with traditional methods of identification of microorganisms. 

The modified method of crystal coating was used to assess Candida spp. The choice of the pathogen was stipulated by the growing importance of this microorganism in the development and maintenance of various pathological conditions, and the lack of quick and reliable methods to identify Candida spp. in practical laboratories. 

Following the same procedure, the crystallograms were characterized by high reproducibility. It normally takes 16-18 h to obtain crystallograms and to identify Candida spp., whereas traditional methods of identification Candida spp. usually... 

The use of the crystallographic method allows significantly acceleration and simplification in the identification of Candida spp. when compared with traditional methods of recognition of the given microorganisms. 

The use of the proposed crystallographic method accelerates and simplifies the identification of the Candida spp. when compared with conventional methods of their identification. 

Antimicrobial activity of the medication was determined by the agar diffusion method [4, 5]. A wide spectrum of pyogenic microflora (Table 16.1) as well as Candida spp. and Helicobacter pylori were studied as test cultures. 

Gatfield et al. [44] reported in 2001 a method to produce natural ethyl E,Z)-2,4-decadienoate, the impact compound of pear. Immobilised lipase from Candida antarctica is capable of transesterifying Stillingia oil in the presence of ethanol. By this process, a complex mixture of ethyl esters is generated. By fractional distillation, the ethyl ester of ( ,Z)-2,4-decadienoate can be isolated from the mixture in a total yield of about 5% and with a high degree of purity. As only... 

Enantioselective enzymatic transesterifications have been used as a complementary method to enantioselective enzymatic ester hydrolyses. The first example of this particular type of biotransformation is the synthesis of the optically active 2-acetoxy-l-silacyclohexane (5 )-78 (Scheme 19). This compound was obtained by an enantioselective transesterification of the racemic l-silacyclohexan-2-ol rac-43 with triacetin (acetate source) in isooctane, catalyzed by a crude lipase preparation from Candida cylindracea (CCL, E.C. 3.1.1.3)62. After terminating the reaction at 52% conversion (relative to total amount of substrate rac-43), the product (S)-78 was separated from the nonreacted substrate by column chromatography on silica gel and isolated in 92% yield (relative to total amount of converted rac-43) with an enantiomeric purity of 95% ee. The remaining l-silacyclohexan-2-ol (/ )-43 was obtained in 76% yield (relative to total amount of nonconverted rac-43) with an enantiomeric purity of 96% ee. Repeated recrystallization of (R)-43 led to an improvement of enantiomeric purity by up to >98% ee. Compound (R)-43 has already earlier been prepared by an enantioselective microbial reduction of the l-silacyclohexan-2-one 42 (see Scheme 8)53. The l-silacyclohexan-2-ol (R)-43 is the antipode of compound (.S j-43 which was obtained by a kinetic enzymatic resolution of the racemic 2-acetoxy-l-silacyclohexane rac-78 (see Scheme 15)62. For further enantioselective enzymatic transesterifications of racemic organosilicon substrates, with a carbon atom as the center of chirality, see References 64 and 70-72. 

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