Characterization of Candida krusei strains from spontaneously fermented maize dough by profiles of assimilation, chromosome profile, polymerase chain reaction and restriction endonuclease analysis

Abstract

A .E . H A YF OR D AN D M . JA KO B SE N. 1999. Several isolates of Candida krusei from indigenous spontaneously fermented maize dough have been characterized for the purpose of selecting appropriate starter cultures and methods for their subspecifies typing. The present work describes the occurrence of C. krusei in Ghanaian fermented maize dough. For detailed pheno-and genotyping, 48 representative isolates were selected and comparison was made with clinical isolates of C. krusei and reference cultures. The techniques applied included the assimilation of carbon compounds by the API ID 32 C kit, determination of chromosome profile by pulse field gel electrophoresis, polymerase chain reaction (PCR) profiles, restriction endonuclease analysis (REA) and Southern blot hybridization. For the 48 isolates tested, 82% had the same assimilation profiles, being able to assimilate N-acetyl-glucosamine, DL-lactate, glycerol and to ferment glucose. Chromosome and PCR profiles, REA and Southern blot hybridization techniques all had a high discriminatory power and revealed DNA polymorphism, which allowed for discrimination among the strains and hence subspecific typing. On the basis of PCR and REA profiles, isolates were grouped into clusters. Southern blot hybridization appeared to be the most sensitive with respect to strain specificity. Our results demonstrated that the three methods, PCR, REA and Southern blot hybridization, were suitable tools, easy to analyse, fast (with regard to PCR) and reliable methods for the typing of C. krusei isolates to species and below species level. Based on the use of these techniques, we demonstrated that several strains of C. krusei were involved in the fermentation of maize dough from the onset and remain dominant throughout the fermentation.

Volatile compounds produced by Lactobacillus fermentum, Saccharomyces cerevisiae and Candida krusei in single starter culture fermentations of Ghanaian maize dough

“…Previous work by Hayford and Jakobsen (1999), Hayford and Jespersen (1999) and Hayford et al (1999) have confirmed to species and strain level, the dominant microflora in Ghanaian fermented maize dough to be L. fermentum , S. cerevisiae and C. krusei . The primary fermentation products of heterofermentative lactic acid bacteria include lactic acid, acetic acid and diacetyl (Lindsay 1985).…”

Evaluation of diversity of Candida species isolated from fermented cassava during traditional small scale gari production in Nigeria

“…The inadequacy of the use of phenotypic method to differentiate C. inconspicua, C. krusei and C. rugopelliculosa in the previous studies have been responsible for the inability to determine the roles (functional and virulence) of these strains during cassava fermentation. Although, C. rugopelliculosa has been previously used for waste water treatment (Lim, Kim, & Swang, 2003) and strains of C. krusei have been consistently isolated from cassava and cereal fermentation in West Africa (Hayford & Jakobsen, 1999).…”

“…Different molecular techniques such as PFGE and REA are used for the characterization of Candida. Although this produces high discrimination, these techniques are expensive and laborious (Hayford & Jakobsen, 1999).…”

“…Different forms of microorganisms principally lactic acid bacteria and yeasts have been reported during gari production, since the fermentation is a natural process with the use of rudimentary utensils (Brauman, Keleke, Malonga, Miambi, & Ampe, 1996;Sanni, 1993 Lactobacillus, Bacillus species co-metabolism with Saccharomyces cerevisiae and Candida krusei has been reported previously as the main group of microorganisms associated with the fermentation of cassava and cereal in Africa (Brauman et al, 1996;Hayford & Jakobsen, 1999). Similar groups of microorganisms were reported for cereal fermentation during ogi, plam wine and burukutu production (Odunfa, 1985).…”

“…Candida tropicalis, Candida glabrata, Candida parapsilosis, C. krusei, and Candida lusitaniae are often isolated from fermented food (Hayford & Jakobsen, 1999;Oyewole, 2001). The increase of infections due to non-Candida albicans species such as C. glabrata and C. krusei (Fidel, Vazquez, & Sobel, 1999;Samaranayale & Samaranayale, 1994), made it very necessary to conduct adequate characterization to be able to identify the species of Candida isolated from fermented food.…”