Pectinolytic activity secreted by yeasts isolated from fermented citrus molasses

Abstract

Aims: The aim of this study was to obtain improved strains of pectinolytic yeasts adapted to the conditions of an industrial fermentation process, which was continuously operated to convert citrus molasses into ethanol. Methods and Results: The starter yeast of the industrial fermentation process was a commercial baker's yeast, which was capable of growing without forming any secretion halo of pectinase activity on solid medium. Nevertheless, isolates showing secretion of pectinolytic activity on plates were obtained from the fermentation process. The secretion of pectin‐degrading activity by isolates on plates was repressed by galactose and improved as the result of colony aging on polygalacturonic acid plates at 30°C. Liquefaction of polygalacturonate gels as well as the splitting of the pectin‐degrading activity into a wall‐linked and a supernatant fraction were also observed when the starter yeast was propagated under agitation in liquid medium containing pectin. Conclusions: Isolates capable of secreting pectinolytic activity on plates were predominant at the end of the citrus molasses fermentation. Nevertheless, the sizes of the secretion haloes on plates were not necessarily an indication of the levels of pectinolytic activity secreted in the liquid medium. Significance and Impact of the Study: Improved pectinolytic strains of Saccharomyces can be used as a source of pectinases for a variety of applications. This organism also participates in plant deterioration processes.

Enzymatic activities produced by mixed Saccharomyces and non-Saccharomyces cultures: relationship with wine volatile composition

“…Higher alcohols (cis-3-hexen-1-ol and 1-hexanol) that negatively correlated to enzymatic activities are associated with compounds that are formed during pre-fermentation steps including harvesting, transport, crushing and pressing (Oliveira et al 2006). This is not surprising since previous reports relate about biosynthesis of these compounds by enzymes not assayed in the present study (Sánchez Palomo et al 2007).…”

In-situ microbial degumming technology with Bacillus sp. HG-28 for industrial production of ramie fibers

“…Pectinase activity was determined according to the method described by Oliveira, Malavolta, Souza, Vicente and Laluce [20]. Xylanase and cellulase activities were measured as described by Brühlmann [21].…”

Polygalacturonase secreted by yeasts from Brazilian semi-arid environments

“…However, yeasts are an alternative source for the large-scale production of commercial enzymes, and they have advantages compared with filamentous fungi with regard to the production of pectinases, because their growth is relatively simple, and the growth culture medium does not require an inducer (Silva et al 2005). Yeasts of the genera Kluyveromyces, Saccharomyces, Stephanoascus, Pichia, Zygosaccharomyces, Candida, Debaryomyces, Pseudozyma, Cryptococcus, Leucosporidium, Metschnikowia, Rhodotorula, Torulaspora, Trichosporon, Kloeckera, Ambrosiozyma, Bullera, Geotrichum, Rhodosporidium and Saccharomycopsis, in addition to the yeast-like Aureobasidium and black yeasts, have been documented as capable of producing pectinases (Biely and Sláviková 1994;Strauss et al 2001;Buzzini and Martini 2002;Trindade et al 2002;Silva et al 2005;Oliveira et al 2006).…”