Elsa Almeida-Vara

Decolourisation of Remazol Brilliant Blue R via a novel Bjerkandera sp. strain.

A novel strain of Bjerkandera sp. (B33/3), with particularly high decolourisation activities upon Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated. The role of the ligninolytic extracellular enzymes produced by this strain on decolourisation of RBBR was studied in some depth. The basis of decolourisation is an enzyme-mediated process, in which the main enzyme responsible is a recently described peroxidase with capacity for oxidation of manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in a manganese-independent reaction.

Searching for a strategy to gamma-sterilize Portuguese cork stoppers — preliminary studies on bioburden, radioresistance and sterility assurance level

Abstract A gamma radiation plant will start running next year in Portugal, to sterilize medical devices and wine cork stoppers. As Portugal is the first world producer, manufacturer and exporter of wine cork stoppers, an efficient sterilizing procedure is required to overcome moulding from long term shipping. Preliminary research on cork stoppers bioburden and microflora radioresistance allowed to establish reliable D10 and Sterility Assurance Level (SAL) values. Studied samples showed an initial average contamination of about 104 c.f.u. per cork stopper. The determined D10 values for fungi were not higher than 2 kGy. In these conditions, a SAL of 10-4 can be expected when the product is treated at a minimum absorbed dose of 15 kGy.

Molecular assessment of microbiota structure and dynamics along mixed olive oil and winery wastewaters biotreatment

The major parcel of the degradation occurring along wastewater biotreatments is performed either by the native microbiota or by added microbial inocula. The main aim of this study was to apply two fingerprinting methods, temperature gradient gel electrophoresis (TGGE) and length heterogeneity-PCR (LH-PCR) analysis of 16S rRNA gene fragments, in order to assess the microbiota structure and dynamics during mixed olive oil and winery wastewaters aerobic biotreatment performed in a jet-loop reactor (JLR). Sequence homology analysis showed the presence of bacterial genera Gluconacetobacter, Klebsiella, Lactobacillus, Novosphingobium, Pseudomonas, Prevotella, Ralstonia, Sphingobium and Sphingomonas affiliated with five main phylogenetic groups: alpha-, beta- and gamma-Proteobacteria, Firmicutes and Bacteroidetes. LH-PCR analysis distinguished eight predominant DNA fragments correlated with the samples showing highest performance (COD removal rates of 67 up to 75%). Cluster analysis of both TGGE and LH-PCR fingerprinting profiles established five main clusters, with similarity coefficients higher than 79% (TGGE) and 62% (LH-PCR), and related with hydraulic retention time, indicating that this was the main factor responsible for the shifts in the microbiota structure. Canonical correspondence analysis revealed that changes observed on temperature and O2 level were also responsible for shifts in microbiota composition. Community level metabolic profile analysis was used to test metabolic activities in samples. Integrated data revealed that the microbiota structure corresponds to bacterial groups with high degradative potential and good suitability for this type of effluents biotreatments.