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Sao Pedro de, Portugal

Amaro H.M.,CIIMAR - Interdisciplinary Center of Marine and Environmental | Guedes A.C.,Catholic University of Portugal | Malcata F.X.,Superior Institute of Maia | Malcata F.X.,New University of Lisbon
Applied Energy | Year: 2011

Carbon-neutral renewable liquid biofuels are needed to displace petroleum-derived transport fuels in the near future - which contribute to global warming and are of a limited availability. A promising alternative is conveyed by microalgae, the oil content of which may exceed 80% (w/wDW) - as compared with 5% of the best agricultural oil crops. However, current implementation of microalga-based systems has been economically constrained by their still poor volumetric efficiencies - which lead to excessively high costs, as compared with petrofuel prices. Technological improvements of such processes are thus critical - and this will require a multiple approach, both on the biocatalyst and bioreactor levels. Several bottlenecks indeed exist at present that preclude the full industrial exploitation of microalgal cells: the number of species that have been subjected to successful genetic transformation is scarce, which hampers a global understanding (and thus a rational design) of novel blue-biotechnological processes; the mechanisms that control regulation of gene expression are not fully elucidated, as required before effective bioprocesses based on microalgae can be scaled-up; and new molecular biology tools are needed to standardize genetic modifications in microalgae - including efficient nuclear transformation, availability of promoter or selectable marker genes, and stable expression of transgenes. On the other hand, a number of pending technological issues are also present: the relatively low microalga intrinsic lipid productivity; the maximum cell concentration attainable; the efficiency of harvest and sequential recovery of bulk lipids; and the possibility of by-product upgrade. This review briefly covers the state of the art regarding microalgae toward production of biofuels, both from the point of view of the microalgal cell itself and of the supporting bioreactor; and discusses, in a critical manner, current limitations and promising perspectives in this field. © 2010 Elsevier Ltd.

Pinto A.M.,Superior Institute of Maia
Proceedings of the 2012 IEEE 13th International Conference on Information Reuse and Integration, IRI 2012 | Year: 2012

We do a survey of some of the most important principles of anonymization present in the literature. We identify different kinds of attacks that can be thrown against an anonymized dataset and give formulas for the maximum probability of success for each. For each principle, we identify whether it is monotonous, what attacks it is suited to counter, if any, and what principles imply other principles. We end by giving a classification of anonymization principles and giving guidelines to choosing the right principle for an application. Although we could not cover all principles in the literature, this is a first step to a systematization and simplification of proposals for anonymization principles. © 2012 IEEE.

Madureira A.R.,Catholic University of Portugal | Amorim M.,Catholic University of Portugal | Gomes A.M.,Catholic University of Portugal | Pintado M.E.,Catholic University of Portugal | And 2 more authors.
Food Research International | Year: 2011

A probiotic whey cheese added with Lactobacillus casei LAFTI®L26, Lactobacillus acidophilus LAFTI®L10 or Bifidobacterium animalis Bo was subject in vitro to sequential conditions that parallel the four major steps of digestion: mouth (artificial saliva), oesophagus-stomach (artificial gastric juice), duodenum (artificial intestinal juice) and ileum; its manufacture followed the traditional cheesemaking protocol of Portuguese Requeijão. MRS broth was inoculated in parallel as reference medium, to ascertain the protective effect of the whey cheese matrix itself upon those strains in every digestion step. Mouth conditions had an almost negligible effect upon all three strains, whereas oesophagus-stomach, duodenum and ileum conditions decreased the viable numbers of L. casei and L. acidophilus; in both systems, B. animalis suffered only slight decreases in viable numbers; and L. casei and L. acidophilus behaved likewise in MRS exposed to duodenum and ileum conditions. Whey cheese matrices thus appeared to protect the aforementioned three strains during transit throughout the simulated gastrointestinal system, so they are promising carriers of those probiotic bacteria. © 2010 Elsevier Ltd.

Malcata F.X.,Superior Institute of Maia | Malcata F.X.,CIIMAR - Interdisciplinary Center of Marine and Environmental | Malcata F.X.,New University of Lisbon
Trends in Biotechnology | Year: 2011

Microalgae have much higher lipid yields than those of agricultural oleaginosous crops, and they do not compromise arable land. Despite this, current microalga-based processes suffer from several constraints pertaining to the biocatalyst and the bioreactor, which hamper technologically and economically feasible scale-up. Here, we briefly review recent active research and development efforts worldwide, and discuss the most relevant shortcomings of microalgal biofuels. This review goes one step further relative to related studies, because it tackles otherwise scarcely mentioned issues - for example, heterotrophic versus autotrophic metabolism, alkane versus glyceride synthesis, conduction versus bubbling of CO 2, and excretion versus accumulation of lipids. Besides promising solutions that have been hypothesized and arise from multidisciplinary approaches, we also consider less conventional ones. Microalgae and biofuels hold indeed a promising partnership, but a fully competitive technology is not expected to be available before the end of this decade, because the need for one order of magnitude increase in productivity requires development of novel apparatuses and transformed cells. © 2011.

Peres C.M.,New University of Lisbon | Peres C.M.,Institute Biologia Experimental e Tecnologica | Peres C.,Institute Biologia Experimental e Tecnologica | Hernandez-Mendoza A.,New University of Lisbon | And 3 more authors.
Trends in Food Science and Technology | Year: 2012

Consumption of functional probiotic foods has increased over recent decades, alongside with increasing consumer and researcher awareness of their health-promoting effects. This has prompted an interest toward development of novel functional food formulations. Despite fermented dairy products still remaining the most common vectors for the delivery of probiotics to humans, such other food matrices as fruits and vegetables offer a promising performance as sources and carriers of probiotic strains. Hence, these types of matrices are thoroughly reviewed here - with table olives being subjected to comprehensive discussion as a case study, owing to their suitable microstructure and unique sensory and nutritional features. © 2012 Elsevier Ltd.

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