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Biofilm-based microalgae cultivation techniques are promising technologies to overcome several issues of suspended cultivations, although only a few large-scale systems have been examined so far. In this study, a rotating biological contactor-based laboratory-scale Algadisk reactor of 0.39 m 2 was tested under low light intensity, and then scaled up to 15.9 m 2 and operated for 6 months in outdoor conditions in order to test its stability and biomass production efficiency with Chlorella sorokiniana . The highest biomass productivity observed in the lab-scale reactor on disk surface base was 3.2 g (m 2 day) − 1 with a 0.9 g mol − 1 biomass yield on light and 208 g kg − 1 dry weight content in biofilm. Due to pH crashes, extreme temperature variations, CO 2 limitation, and failure of disk rotation, the Algadisk pilot system showed varying biomass productivity from 0.5 to 8.4 g (m 2 day) − 1 on reactor footprint area. Also, biomass yield on light and biomass density remained lower than at laboratory scale. Nonetheless, a total of 7.4 kg CO 2 was fixed in the biofilm during the operating time. Despite the difficulties and the complexity of the system, over 20 weeks of continuous operation was achieved without the need of reinoculation.

Significant part of not cultivated area of Hungary is not suitable for agricultural utilization because of industrialpollution. Technologies of biorefinery make reutilization of contaminated areas possible. Biomass of plantsproduced on polluted soils can be raw material of valuable products. Applicability of biorefinery was tested on aheavy metal polluted soil, where the contamination originated from previous mining activity. Complete biomassutilization was aimed to obtain cosmetic ingredients, pharmaceutical agents, and precursors. During our researchwork 88 plant species and varieties were produced and tested for potential utilizable components. Levels ofpossible contaminants in these plants were monitored, and amounts of carbohydrates, protein, organic acid andcellulose were determined as well. Different plant extracts were tested as potential sources of biologically effectivecomponents or as raw materials for lactic acid fermentation. Our results show that biorefinery is a real possibilityfor utilization of polluted areas. Numerous plants could be cultivated on contaminated areas without increasedlevels of contaminants in their tissues, thus they can be sources of valuable compounds.

Pseudomonas aeruginosa is able to form exopolysaccharide biopolymer in the lungs of cystic fibrosis patients, increasing viscoelasticity of sputum. In our studies, the viscosity of the biopolymer produced by P. aeruginosa 1604 was investigated in the presence of aspirin and sodium salicylate. The applied salicylic compounds in 0.3 % concentration decreased significantly the viscosity of the biopolymer during a five days period. The biopolymer of P. aeruginosa can harbour other virulence factors, such as pyocyanin. The applied salicylic compounds also decreased the pyocyanin production; however, according to our results P. aeruginosa 1604 was able to produce pyocyanin after 72 h in the presence of 0.1-0.2 % salicylic compounds. Consistent low pyocyanin production was caused only in the presence of 0.3 % or higher concentration of these compounds.Consequently, salycilic compounds decreased both the viscoelasticity of the biopolymer and the concentration of pyocyanin produced by P. aeruginosa 1604.e viscoelasticity of the biopolymer and the concentration of pyocyanin produced by P. aeruginosa 1604 .