| Congresso Brasileiro de Microbiologia 2023 | Resumo: 986-1 | ||||
Resumo:The rhamnolipid produced by Pseudomonas aeruginosa is a biosurfactant that has many applications to bioremediation processes due to its bioavailability-enhancing characteristics, including its potential to mobilize heavy metals. The production of such surfactant depends on the bacterial cultivation stage, in which optimization occurs by supplying carbon sources in the culture medium, such as sugarcane molasses. This research aimed to produce biosurfactants from a P. aeruginosa culture by using sugarcane molasses as a substrate to optimize bacterial growth and rhamnolipid production. The isolation procedure was performed in cetrimide culture medium (specific medium) from a eight soil samples collected in Araras – SP. The straind from the samples were submitted to identification tests (indole, Gram and catalase). Then, the cultures with matching results were cultivated in Nutirent Agar (NA) medium with 3% sugarcane molasses and 3% sodium nitrate, maintained for 10 hours in a shaker at 200 rpm at 38°C. Subsequent enrichments were carried out in NA medium, at the same concentration, for 96 hours at 100 rpm and 38°C. The broth was centrifuged and subjected to the surface tension breakdown test. In the emulsification test, the supernatant, mineral oil, and water were vortexed for 1 min and kept overnight for 24 h. The tubes underwent E24 analysis, where the emulsified height were measured in relation to the total volume. The results of the identification test indicated that P. aeruginosa was successfully isolated. The water surface tension breakage test showed a significant positive result, and the E24 test, carried out in duplicate, resulted in 37,0% of biosurfactant emulsion with the oil, whereas control assays containing chemical surfactant yielded 39.8% emulsification. The qualitative burette drop method measured the surface tension of the surfactant, medium without surfactant and water, showing a substantial decrease in surface tension when the produced biosurfactant was tested. Through the results obtained, it was verified that the culture of the bacteria produces biosurfactant using sugarcane molasses as substrate, allowing the application of processes of optimization and separation of the produced surfactant. Palavras-chave: rhamnolipids, emulsification, surfactant, bacteria, identification Agência de fomento:CNPq (National Council for Scientific and Technology Development) | |||||