Biosurfactant synthesis by Pseudomonas aeruginosa LBI isolated from a hydrocarbon-contaminated site.

AIMS: Pseudomonas aeruginosa LBI (Industrial Biotechnology Laboratory) was isolated from hydrocarbon-contaminated soil as a potential producer of biosurfactant and evaluated for hydrocarbon biodegradation. The emulsifying power and stability of the product was assessed in the laboratory, simulating water contamination with benzene, toluene, kerosene, diesel oil and crude oil at various concentrations. METHODS AND RESULTS: Bacteria were grown at 30 degrees C and shaken at 200 rpm for 168 h, with three repetitions. Surface tension, pH and biosurfactant stability were observed in the cell-free broth after 168 h of incubation. The strain was able to produce biosurfactant and grow in all the carbon sources under study, except benzene and toluene. When cultivated in 30% (w/v) diesel oil, the strain produced the highest quantities (9.9 g l(-1)) of biosurfactant. The biosurfactant was capable of emulsifying all the hydrocarbons tested. CONCLUSION: The results from the present study demonstrate that Ps. aeruginosa LBI can grow in diesel oil, kerosene, crude oil and oil sludge and the biosurfactant produced has potential applications in the bioremediation of hydrocarbon-contaminated sites. SIGNIFICANCE AND IMPACT OF THE STUDY: Pseudomonas aeruginosa LBI or the biosurfactant it produces can be used in the bioremediation of environmental pollution induced by industrial discharge or accidental hydrocarbon spills.

[Bone distraction using an external fixator: a new mandibular lengthening technic. A preliminary study apropos of 2 cases of children with mandibular hypoplasia]. / La distraction osseuse par fixateur externe: une nouvelle technique d'allongement mandibulaire. Etude préliminaire à propos de deux observations chez l'enfant porteur d'une hypoplasie mandibulaire.

The authors expose a technical innovation concerning mandibular lengthening without any bone graft, by applying to the mandibular Ilizarov's principles about limb lengthening by osseous distraction. This surgical technique concerns children with mandibular hypoplasia, like the Hanhart's syndrome (aglossia-adactylia, first observation), or Hemifacial Microsomia (second observation). The purpose of this new technique is mandibular lengthening with functional and aesthetic correction of the mandibular growth deficiency, and minimal morbidity. A specialist staff is essential to realize a distraction device with his minimal and appropriate shape for children, as well as a protection device conception. This external distraction device is placed with transmandibular pins. After mandibular corticotomy by endobuccal incision, the distraction is accomplished, at home by the parents, at the rythm of 1 mm p. two days. The distraction goes on about 2 months, depending on the lack of mandibular growth, and a retention device, much more light, is necessary during 8 weeks more to stabilize the osteogenesis. At the term of an eight weeks gradual distraction, the mandibular lengthening is 17.5 mm for the horizontal ramus (first observation), and 13 mm for the vertical ramus (second observation). The functional and aesthetic results, the swift and secure surgical procedure, lead to put forward this mandibular distraction technique in any mandibular or facial defects.