RESUMO Biossurfactantes são moléculas multifuncionais produzidas por microrganismos e podem apresentar vantagens em relação aos surfactantes sintéticos, como baixa toxicidade, alta biodegradabilidade, maior redução da tensão superficial e alta diversidade química. No entanto, a produção em escala comercial ainda é escassa devido ao elevado custo dos substratos utilizados. Portanto, no presente trabalho foi avaliada a produção de biossurfactantes utilizando diferentes óleos como fonte de carbono, como óleo de soja, óleo de fritura, óleo diesel, óleo lubrificante novo e usado, a partir de dois gêneros de bactérias isoladas de lodo indústria de cosméticos e solo contaminado com óleo diesel, Lysinibacillus sp. e Bacillus sp. respectivamente. Estas foram identificadas por sequenciamento do fragmento do gene RNAr 16S e mantidas sob refrigeração a 4 ºC em tubos de ensaio, com ágar triptona de soja. Os ensaios de produção foram realizados sob agitação de 200 rpm a 30 °C com duração de 7 dias. A produção de biossurfactante foi analisada pela atividade emulsificante, índice emulsificação e por colapso da gota. As bactérias utilizadas produziram biossurfactante em todos os tipos de óleos testados. O óleo de soja mostrou-se o melhor substrato para produção de biossurfactante a partir do Lysinibacillus sp. e Bacillus sp. com índice de emulsificação de 50 % e 46,63 %, respectivamente.

ABSTRACT Biosurfactants are multifunctional molecules produced by microorganisms and havea some advantages compared to synthetic surfactants, such as low toxicity, high biodegradability ,improved tensoactivity and chemical diversity. However, commercial scale production is not viable due to the high cost of the substrates used. Therefore, in the present work we evaluated the production of biosurfactants using different oils as carbon source, such as soybean oil, frying oil, diesel oil, new and used lubricating oil, from two genera of bacteria isolated from sludge cosmetics industry and soil contaminated with diesel oil, Lysinibacillus sp. and Bacillus sp. respectively. These were identified by sequencing the 16S rRNA gene fragment and kept under refrigeration at 4 ° C in test tubes with tryptone soy agar. The production was carried out under agitation at 200 rpm at 30 °C for 7 days. The biosurfactant production was analyzed by emulsifying activity, emulsification index and drop collapse. The bacteria used produced biosurfactant in all types of oils tested. Soybean oil was the best substrate for the production of biosurfactant from Lysinibacillus sp. and Bacillus sp. with an emulsification index of 50% and 46.63%, respectively.

The objective of this study was to evaluate the degradation of Linear Alkylbenzene Sulfonate (LAS) in anaerobic sequencing batch reactor (ASBR) under denitrifying conditions using swine sludge as inoculum. The reactor was operated for 104 days with synthetic substrate containing nitrate, and LAS was added later (22 mg/L). Considering the added mass of the LAS, the adsorbed mass in the sludge and discarded along with the effluent, degradation of the surfactant at the end of operation was 87%, removal of chemical oxygen demand was 86% and nitrate was 98%. The bacterial community was evaluated by cutting the bands and sequencing of polymerase chain reaction (PCR) fragments and denaturing gradient gel electrophoresis (DGGE). The sequences obtained were related to the phylum Proteobacteria and the alpha-and beta-proteobacteria classes, these bacteria were probably involved in the degradation of LAS. The efficiently degraded LAS in the reactor was operated in batch sequences in denitrifying conditions.