Browsing by Author "Valente, Patrícia"
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Item Bacteria and yeasts associated to Colonial cheese production chain and assessment of their hydrolytic potential | [Bactérias e leveduras associadas às etapas de produção de queijo Colonial e avaliação de seu potencial enzimático](2021) de Souza, Priscilla Vieira; Zaffari Grecellé, Cristina B.; Barreto, Fabiano; Ramírez Castrillon, Maurício; Valente, Patrícia; da Costa, MarisaDifferent types of microorganisms are important in cheese-making because of the contributions their metabolism offers during the process. Few microorganisms present in Colonial cheese are known, in addition to the ones that are introduced to kick-start the processes or the ones that are associated with infections or poisonings. This study aimed to identify, by MALDI-TOF and/or DNA sequencing, the bacteria and yeasts isolated from samples collected in the main stages of Colonial cheese production, i.e., a type of cheese produced in the southern region of Brazil. The lytic capacity of these microorganisms at 5 °C and 30 °C was also evaluated. The 58 bacterial strains were distributed in 10 species among the genera Bacillus, Citrobacter, Klebsiella, Lactococcus, Paenibacillus, Staphylococcus and Raoutella. From the 13 yeasts strains analyzed, three species were identified as following: Candida pararugosa; Meyerozyma guilliermondii; and Rhodotorula mucilaginosa. In three yeasts isolates it was possible to identify only the genus Candida sp. and Trichosporon sp. The species L. lactis (48%) and M. guilliermondii (46%) were, respectively, the predominant bacteria and yeasts species isolated. The highest microbial lytic activity observed was at 30 °C. Lipase activity on isolates was proportionally more observed with yeasts and proteolytic activity with bacteria. Lower caseinase and lipase activity was observed at 5 °C, demonstrating the importance of refrigeration in controlling microbial activity. This research highlighted the cultivation of some microorganisms that are part of the Colonial cheese microbiota as well as that several of them can hydrolyze various compounds present in milk and that could be associated with its maturation or, in uncontrolled circumstances, could be the cause of product deterioration. © 2021 Instituto de Tecnologia de Alimentos - ITAL. All rights reserved.Item The oleaginous yeast Meyerozyma guilliermondii BI281A as a new potential biodiesel feedstock: Selection and lipid production optimization(Frontiers Media S.A., 2017-09-22) Ramírez-Castrillón, Mauricio; Jaramillo-García, Victoria P.; Rosa, Priscila D.; Landell, Melissa Fontes; Vu, Duong; Fabricio, Mariana F.; Ayub, Marco Antônio Záchia; Robert, Vincent A.R.G.; Henriques, João Antonio Pêgas; Valente, PatríciaA high throughput screening (HTS) methodology for evaluation of cellular lipid content based on Nile red fluorescence reads using black background 96-wells test plates and a plate reader equipment allowed the rapid intracellular lipid estimation of strains from a Brazilian phylloplane yeast collection. A new oleaginous yeast, Meyerozyma guilliermondii BI281A, was selected, for which the gravimetric determination of total lipids relative to dry weight was 52.38% for glucose or 34.97% for pure glycerol. The lipid production was optimized obtaining 108 mg/L of neutral lipids using pure glycerol as carbon source, and the strain proved capable of accumulating oil using raw glycerol from a biodiesel refinery. The lipid profile showed monounsaturated fatty acids (MUFA) varying between 56 or 74% in pure or raw glycerol, respectively. M. guilliermondii BI281A bears potential as a new biodiesel feedstock. © 2017 Ramírez-Castrillón, Jaramillo-Garcia, Rosa, Landell, Vu, Fabricio, Ayub, Robert, Henriques and Valente.