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[Excerpt] Contamination of foodstuffs and agriculture commodities by mycotoxin-producing fungi is an increasingly severe problem, not only due to the substantial economic losses caused by the significant reductions in crop yield, but also to their toxicity to humans and animals. Mycotoxins are a heterogeneous group of extremely toxic secondary metabolites synthesized by certain filamentous fungi such as Aspergillus spp. that exhibit carcinogenic, mutagenic and teratogenic activities. Consequently, maximum allowable concentrations of mycotoxins in food and feed have been established. Several strategies including chemical, physical and biological methods have been investigated to reduce fungal and mycotoxins contamination in crops. Among them, biological control is one of the most promising approaches to overcome mycotoxins contamination in both pre- and post-harvested crops. [...], info:eu-repo/semantics/publishedVersion

Book of Abstracts of CEB Annual Meeting 2017, [Excerpt] Surfactants are one of the most important classes of industrial chemicals in terms of production volume. These compounds exhibit a wide variety of applications in several industries and are present in nearly every product and aspect of our daily life. They can be found in detergents, laundry formulations, household cleaning products, cosmetics, herbicides or pesticides, and are also used in bioremediation, agriculture, food, pharmaceutical, textile, paper or the petroleum industries, among others. Most conventional surfactants available nowadays are derived from non-renewable resources and their use may lead to significant ecological problems due to their toxicity and low biodegradability. In the recent years, an increase in environmental awareness has led to much more interest in the use of renewablebased, biodegradable and more environmentally friendly surfactants. Among them biosurfactants, surface-active compounds synthesized by microorganisms, are attracting a pronounced interest due to their potential advantages over their synthetic counterparts, and to the fact that they could replace some of the synthetics in many environmental and industrial applications. [...], info:eu-repo/semantics/publishedVersion

RICI7 - VII Iberian Meeting on Colloids and Interfaces, Rhamnolipids are a class of glycolipid biosurfactants produced mainly by Pseudomonas aeruginosa strains. Their structure comprises one or two rhamnose molecules linked to one or two -hydroxy fatty acids which can differ in the chain length and the degree of saturation. Rhamnolipids display a similar or better performance when compared with chemical surfactants, and exhibit higher biodegradability and lower toxicity, which make them potential alternatives to the synthetic surfactants in several applications [1]. Among them, rhamnolipids can be used as an alternative to the chemical fungicides to prevent the contamination and deterioration of agriculture products by fungi. In this work, the antifungal activity of rhamnolipids produced by P. aeruginosa #112 was evaluated against Aspergillus niger MUM 92.13 and Aspergillus carbonarius MUM 05.18. These species are among the most common fungal contaminants, and represent a health risk due to the production of mycotoxins. P. aeruginosa #112 produced eight different rhamnolipid congeners (including mono- and di-rhamnolipids). The growth inhibition percentages obtained for both fungi with the crude rhamnolipid mixture (3 g/L) were between 22 and 28%. Subsequently, it was studied the effect of different electrolytes in the antifungal activity of rhamnolipids. It was found that the growth of A. carbonarius MUM 05.18 and A. niger MUM 92.13 was completely inhibited by a combination of the crude rhamnolipid mixture (3 g/L) and NaCl (at concentrations between 375 and 875 mM). In order to establish a relationship between the antifungal activity and the aggregation behavior of rhamnolipids, the size distribution of the self-assembled structures formed by the crude rhamnolipid mixture in aqueous solution was studied at different NaCl concentrations through Dynamic Light Scattering. In the absence of NaCl, rhamnolipids formed micelles with an average size around 300 nm. The addition of NaCl resulted in an increase in the size of the structures formed, and for the highest NaCl concentration tested (875 mM), the average size of the self-assembled vesicles was higher than 2 µm. The formation of these large vesicles by rhamnolipids in the presence of NaCl was confirmed through Confocal Scanning Laser Microscopy. The results obtained demonstrated a relationship between the antifungal activity of rhamnolipids and their aggregation behavior, which opens the possibility to improve their biological activities for application in different fields., info:eu-repo/semantics/publishedVersion

As lipases (E.C. 3.1.1.3) são um grupo de enzimas capazes de catalisar a hidrólise da ligação éster de triacilgliceróis, gerando ácidos graxos livres e glicerol. As lipases microbianas são muito utilizadas nas aplicações industriais nas áreas de alimentos, síntese orgânica e farmacêutica. Neste trabalho, visando à produção de lipase a partir da levedura Candida rugosa foram utilizados meios de cultura alternativos compostos por melaço, milhocina e águas russas. As fermentações foram conduzidas em agitador rotatório a 30 °C e 170 rpm. Testaram-se quatro meios contendo diferentes combinações dos resíduos acima mencionados. O meio contendo melaço 10 g/L, milhocina 4 g/L e águas russas 1,0 %(v/v) foi o que propiciou a produção de enzima com maior atividade intracelular 269 ± 10 U/L frente ao substrato pNFL (p-nitrofenil laurato). Esses resultados demonstram que o referido meio alternativo contendo resíduos agroindustriais é adequado para a produção de lipase.