INVESTIGADORES
LOTO Flavia Del Valle
artículos
Título:
Selection of Psychrotolerant Microorganisms Producing Cold-Active Pectinases for Biotechnological Process at Low Temperature
Autor/es:
CABEZA, M. SILVINA; BACA, FANNY; MUÑOZ PUNTES, ERNESTO; LOTO FLAVIA; BAIGORI, MARIO; MORATA, VILMA
Revista:
FOOD TECHNOLOGY AND BIOTECHNOLOGY
Editorial:
FACULTY FOOD TECHNOLOGY BIOTECHNOLOGY
Referencias:
Lugar: Croacia; Año: 2011 vol. 49 p. 187 - 195
ISSN:
1330-9862
Resumen:
Low temperatures in winemaking favor the production and retention of flavor and 31 color components, requiring the use of cold active enzymes. For this reason, 32 “psychrotolerant” microorganisms were isolated and selected according to production of 33 pectinolytic enzymes with satisfactory activity at low temperatures. Different mature grape 34 varieties were sampled from the enological D.O. (Designation of Origin) region San Rafael 35 (Mendoza, Argentina), isolating pectinolytic bacterial, fungal and yeast strains. The 36 pectinolytic activity was measured by cup-plate assay, quantification of released reducing 37 sugars and viscosity reduction of pectin solution. Two bacteria and 2 yeast strains were 38 selected for their good pectinase activity at low temperatures. From them, the strain with 39 highest activity, Bacillus sp. SC-H, was selected. According to their 16S rRNA profiles, 40 Bacillus sp. SC-G and B. sp. SC-H can been classified as members of Bacillus subtilis 41 group. From the assayed techniques, the rotavapor concentration was found to be the most 42 appropriate technique to achieve enzymatic extracts with greatest activity. The optimal 43 conditions for the enzymatic action were 30 ºC and pH=5.0 for the concentrated extract, 44 and 45 ºC and pH=6.0 for the filtrated supernatant. The concentrated extract presented good 45 activity at 3 ºC, confirming that it was a cold-enzyme. The performance of the enzymatic 46 extract was assayed in the extraction of pigments (index, shade, Cie-Lab coordinates and 47 Cie-Lab color differences) and polyphenols (using Folin-Ciocalteau) from Malbec grapes, 48 showing better results than natural extraction. <!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:595.3pt 841.9pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:35.4pt; mso-footer-margin:35.4pt; mso-paper-source:0;} div.Section1 {page:Section1;} -->