Abstract The use of native species’ stem cuttings in riparian forests disturbed by silting could be a promising low-tech alternative for restoration practitioners in riverscape rehabilitation. In this study, we evaluated the vegetative propagation of Amazonian native plants (Buchenavia parviflora, Euterpe oleracea, Ficus insipida and Socratea exorrhiza) with the addition of a bio-fertilizer, and humic and fulvic acids in soil disturbed by human-induced silting. We found that F. insipida and B. parviflora were able to grow and showed high survival percentage with the development of leaves, buds, and roots; even in nutrient deficient and clayey soils. We also found that the frequency of application and the concentration of the organic additives did not show significant influence on plants’ development. Thus, advance in situ tests with both species could be an interesting step to contribute to riverine ecosystems restoration practices.

Abstract Biosurfactants have many advantages over synthetic surfactants but have higher production costs. Identifying microorganisms with high production capacities for these molecules and optimizing their growth conditions can reduce cost. The present work aimed to isolate and identify a fungus with high biosurfactant production capacity, optimize its growth conditions in a low cost culture medium, and characterize the chemical structure of the biosurfactant molecule. The fungal strain UFSM-BAS-01 was isolated from soil contaminated with hydrocarbons and identified as Fusarium fujikuroi. To optimize biosurfactant production, a Plackett–Burman design and a central composite rotational design were used. The variables evaluated were pH, incubation period, temperature, agitation and amount of inoculum in a liquid medium containing glucose. The partial structure of the biosurfactant molecule was identified by nuclear magnetic resonance spectrometry. F. fujikuroi reduced surface tension from 72 to 20 mN m−1 under the optimized conditions of pH 5.0, 37 °C and 7 days of incubation with 190 rpm agitation. The partial identification of the structure of the biosurfactant demonstrated the presence of an α,β-trehalose. The present study is the first report of the biosynthesis of this compound by F. fujikuroi, suggesting that the biosurfactant produced belongs to the class of trehalolipids.