Isolation, identification, and screening of biosurfactant-producing and hydrocarbon-degrading bacteria from oil and gas industrial waste

Qatar is one of the biggest oil and gas producers in the world, coupled with it is challenging environmental conditions (high average temperature: >40 °C, low annual rainfall: 46.71 mm, and high annual evaporation rate: 2200 mm) harbors diverse microbial communities that are novel and robust, with the potential to biodegrade hydrocarbons. In this study, we collected hydrocarbon contaminated sludge, wastewater and soil samples from oil and gas industries in Qatar. Twenty-six bacterial strains were isolated in the laboratory from these samples using high saline conditions and crude oil as the sole carbon source. A total of 15 different bacterial genera were identified in our study that have not been widely reported in the literature or studied for their usage in the biodegradation of hydrocarbons. Interestingly, some of the bacteria that were identified belonged to the same genus however, demonstrated variable growth rates and biosurfactant production. This indicates the possibility of niche specialization and specific evolution to acquire competitive traits for better survival. The most potent strain EXS14, identified as Marinobacter sp., showed the highest growth rate in the oil-containing medium as well as the highest biosurfactant production. When this strain was further tested for biodegradation of hydrocarbons, the results showed that it was able to degrade 90 to 100% of low and medium molecular weight hydrocarbons and 60 to 80% of high molecular weight (C35 to C50) hydrocarbons. This study offers many promising leads for future studies of microbial species and their application for the treatment of hydrocarbon contaminated wastewater and soil in the region and in other areas with similar environmental conditions

Expressão fenotípica de clones de seringueira na região noroeste do estado de São Paulo Phenotypic expression of rubber tree clones in the northwestern region of São Paulo state

O desenvolvimento de novos clones de seringueira [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.] com alto potencial de produção aliado a outros caracteres secundários desejáveis é de fundamental importância para uma heveicultura sustentável e competitiva. O objetivo deste trabalho foi avaliar a expressão fenotípica de caracteres superiores em 17 clones de seringueira, tendo em vista a escolha dos mais promissores. Em campo, o experimento obedeceu ao delineamento de blocos ao acaso com três repetições e parcelas lineares de seis plantas. Pelos resultados, verificou-se que o clone IAC 40 foi o mais produtivo, com média de 2.316 kg de borracha seca ha-1 ano-1 no período de seis anos, seguido pelo clone IAC 300 (1.921 kg), enquanto o clone-testemunha, RRIM 600 produziu 1.493 kg. Observou-se na maior parte dos clones, crescimento superior em relação à testemunha. A porcentagem de plantas aptas à sangria variou de 40% (IAC 329) a 100% (IAC 327). Exceto nos clones IAC 56, IAC 331 e IAN 3156 com 7,21 mm, 7,18 mm e 6,40 mm respectivamente, em todos os demais notou-se espessura de casca virgem inferior ao clone RRIM 600 (6,38 mm). Com exceção do IAN 3156, os demais clones tiveram baixa incidência de secamento de painel. O bom desempenho de todos os clones IAC e amazônicos (IAN, Fx e RO) permite que sejam recomendados para plantio em pequena escala, ao tempo em que serão avaliados para futura recomendação em grande escala envolvendo diferentes ambientes do Estado de São Paulo.<br>The development of new clones with high production combined to other desirable secondary characters is fundamental for a sustainable and competitive rubber tree cultivation. The objective of this study was to evaluate, during a period of 13 years, the phenotypic expression of superior characters of 17 clones of rubber tree grown in the plateau region of São Paulo State, Brazil. The treatments were arranged in a randomized block design with three replicates and six plants per linear plot. The clone IAC 40 exhibed the highest yield (2.316 kg ha-1 year-1) followed by IAC 300 (1.921 kg), whereas the control clone RRIM 600 had 1.493 kg ha-1 year-1 over six years of tapping. The percentage of plants able for opening ranged from 40% for IAC 329 to 100% for IAC 327. Except for IAC 56, IAC 331 and IAN 3156, with 7.21 mm, 7.18 mm and 6.40 mm respectively, all other clones had lower thick virgin bark at opening compared to the control clone RRIM 600, which recorded 6.38 mm. Except IAN 3.156 all clones showed low incidence of panel dryness. The good performance of all clones, both from IAC and Amazone (IAN, Fx and RO) allow their recommendation for small scale cultivation, when they would be further tested in different environments of the São Paulo State, aiming recommendations in large scale