getpdf

Selection of Psychrotolerant Microorganisms Producing Cold-Active Pectinases for Biotechnological Processes at Low Temperature

María S. Cabeza1,2, Fanny L. Baca2, Ernesto Muñoz Puntes2, Flavia Loto1,3, Mario D. Baigorí1,3 and Vilma I. Morata1,2*


1
National Council of Scientific and Technical Research (CONICET), Av. Rivadavia 1917, C1033AAJ, Buenos Aires, Argentina

2
Biotechnology Laboratory, Biology and Food Department, Faculty of Applied Industrial Science, Bernardo de Irigoyen 375, AR-5600, San Rafael, Mendoza, Argentina

3
Pilot Plant of Industrial and Microbiological Processes (PROIMI), Av. Belgrano and Pje. Caseros 4000, AR-4000 Tucumán, Argentina

Article history:

Received: July 23, 2009

Accepted: April 28, 2010

Key words:

pectinase, cold-active enzymes, low temperature, Bacillus, pigment and polyphenol extraction

Summary:

In winemaking, low temperatures are favourable for the production and retention of flavour and colour components, requiring the use of cold-active enzymes. For this reason, 'psychrotolerant' microorganisms have been isolated and selected based on their ability to produce pectinolytic enzymes with satisfactory activity at low temperatures. Different mature grape varieties with designation of origin were sampled from the region of San Rafael (Mendoza, Argentina), and pectinolytic bacterial, fungal and yeast strains were isolated. The pectinolytic activity was measured by cup-plate assay, quantification of released reducing sugars and viscosity reduction of pectin solution. Two bacteria (Bacillus sp. SC-G and SC-H) and two yeast strains were selected for their good pectinase activity at low temperatures. Among them, the strain with the highest activity, Bacillus sp. SC-H, was selected. According to their 16S rRNA profiles, Bacillus sp. SC-G and SC-H can be classified as members of Bacillus subtilis. Among the assayed techniques, the rotary evaporation was found to be the most appropriate to obtain enzymatic extracts with highest activity. The optimal conditions for the enzymatic activity were 30 °C and pH=5.0 for the concentrated extract, and 45 °C and pH=6.0 for the filtered supernatant. The concentrated extract presented good activity at 3 °C, confirming that it was a cold-active enzyme. Natural extraction and enzymatic preparation were used to extract pigments and polyphenols from Malbec grapes. Better results were obtained for the enzymatic extract with regard to index, shade, CIELab coordinates, CIELab colour differences and polyphenols (measured using Folin-Ciocalteu).



*Corresponding author:    vmorata@fcai.uncu.edu.ar                             

Search FTB


Follow us


 facebook 1 twitter bird_icon

 

QR Code


qrcode

We use cookies to improve our website and your experience when using it. Cookies used for the essential operation of the site have already been set. To find out more about the cookies we use and how to delete them, see our privacy policy.

I accept cookies from this site.

EU Cookie Directive Module Information