Eighteen aerobic endospore forming strains were isolated from sugarcane rhizosphere in N-free medium. A phenotypic description and analysis of the 5' end hypervariable region sequences of 16S rRNA revealed a high diversity of Bacillus and related genera. Isolates were identified, and four genera were obtained: seven strains belonged to Bacillus (Bacillaceae family), four belonged to Paenibacillus, six belonged to Brevibacillus and one strain was identified as Cohnella (Paenibacillaceae family). Four Brevibacillus strains showed in vitro inhibitory activity against plant pathogens fungi Curvularia and Fusarium. Seventy-four percent of the isolated bacteria grew on pectin as the only carbon source, showing polygalacturonase activity. Pectate lyase activity was detected for the first time in a Brevibacillus genus strain. All isolates showed endoglucanase activity. Calcium phosphate solubilisation was positive in 83.3% of the isolates, with higher values than those reported for Bacillus inorganic phosphate solubilising strains. High ethylene plant hormone secretion in the culture medium was detected in 22% of the bacteria. This is the first report of ethylene secretion in Paenibacillaceae isolates. Indole-3-acetic acid production was found in a Brevibacillus genus isolate. It was reported for the first time the presence of Cohnella genus strain on sugarcane rhizosphere bearing plant growth promoting traits. The sugarcane isolate Brevibacillus B65 was identified as a plant growth inoculant because it showed wider spectra of plant stimulation capabilities, including an antifungal effect, extracellular hydrolases secretion, inorganic phosphate solubilisation and plant hormone liberation. In this work, sugarcane was shown to be a suitable niche for finding aerobic endospore forming 'Bacilli' with agriculture biotechnological purposes.

The creation of pit lakes is usually an acceptable solution from the landscaping point of view for voids left by discontinued open-pit mines. However, without rehabilitation, these voids represent a potential environmental risk. The aim of the present work was to assess, for the first time, the water quality i.e. physico-chemical characteristics, metal and metalloid (MM) content and ecotoxicity of the waters of the El Cobre Blue Lagoon, a pit lake formed in an open-pit copper mine in Cuba. Potential effects of rainy season vs. dry season and spatial location (different depths) on water characteristics were considered. Results revealed that water contained was moderately acidic (pH = 4.6±0.2), with high electrical conductivity (EC = 3.02±0.03 mS.cm-1), whatever the season. Dissolved oxygen (DO = 9.9±2.0 mg.L-1), Total Dissolved Solid (TDS = 7003±245 mg.L-1) and sulfate concentration (6556±1410 mg.L-1) in the El Cobre Blue Lagoon water were above acceptable limits for sources of surface water as recommended by Cuban standard (NC 1021:2014). High copper (43.6±1.7 mg.L-1) and manganese (24.1±1.1 mg.L-1) contents were detected. Except for EC, sulfates, chlorides, TDS, nitrates and phosphates, other physico-chemical parameters were stable between dry and rainy seasons (p<0.05). El Cobre Blue Lagoon waters showed an ecotoxicological impact on Vibrio fischeri. No significant differences were detected between all sampling points in the lake for each parameter monitored for a given time. These first results show the spatial homogeneity but poor quality of waters from El Cobre Blue lagoon. Remediation processes need to be implemented in order to lessen the human and environmental health risk and favor potential water reuse. We suggest the use of constructed wetlands for water treatment. This preliminary research work can serve to alert Cuban local public authorities to the need to rehabilitate such sites.

Palabras clave: remediación, hidrocarburos, diseño Box-Behnken RESUMEN La remoción de hidrocarburos empleando ramnolípidos ha mostrado potencialidades para su aplicación en tecnologías de remediación de ecosistemas impactados, así como en el aumento de la eficiencia de extracción de petróleo en pozos. En esta investigación se evaluó la remoción de hidrocarburos totales de petróleo de un suelo contaminado empleando los ramnolípidos producidos por Pseudomonas aeruginosa ORA9. Se realizó un estudio de estabilidad de los ramnolípidos considerando los factores temperatura, pH y fuerza iónica. Los ramnolípidos fueron estables en las condiciones ensayadas. Se utilizó un diseño Box-Behnken para evaluar la influencia de la temperatura, pH y tiempo de contacto, en la remoción de petróleo de suelo contaminado. Los tres factores influyeron significativamente, incrementándose la extracción al aumentar la temperatura y el tiempo de contacto y disminuir el pH. La máxima extracción alcanzada fue de un 75 %.Key words: remediation, hydrocarbons, Box-Behnken design ABSTRACT Hydrocarbon removal using rhamnolipids has shown potential for use in remediation technologies of impacted ecosystems as well as increasing the efficiency of oil extraction wells. In this research, the removal of total petroleum hydrocarbons in contaminated soil was evaluated using rhamnolipids produced by Pseudomonas aeruginosa ORA9. A stability study of rhamnolipids considering temperature, pH and ionic strength factors was performed. The rhamnolipids were stable in the tested conditions. A Box-Behnken design was employed to evaluate the influence of temperature, pH and contact time on the removal of petroleum from contaminated soil. All factors have a significative influence on the extraction of total petroleum hydrocarbons, increasing with temperature and contact time, and decreasing with pH. The maximum extraction was 75 %.