001- Bao MT, Wang LN, Sun PY, Cao LX, Zou J, Li YM. Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Shandong, Qingdao 266100, China. Biodegradation of crude oil using an efficient microbial consortium in a simulated marine environment. Marine Pollution Bulletin, 2012, 64 (6), 1177 – 85.
Ochrobactrum sp. N1, Brevibacillus parabrevis N2, B. parabrevis N3 and B. parabrevis N4 were selected when preparing a mixed bacterial consortium based on the efficiency of crude oil utilization. A crude oil degradation rate of the N-series microbial consortium reached upwards of 79% at a temperature of 25°C in a 3.0% NaCl solution in the shake flask trial. In the mesocosm experiment, a specially designed device was used to simulate the marine environment. The internal tank size was 1.5m (L) ×0.8m (W) ×0.7m (H). The microbial growth conditions, nutrient utilization and environmental factors were thoroughly investigated. Over 51.1% of the crude oil was effectively removed from the simulated water body. The escalation process (from flask trials to the mesocosm experiment), which sought to represent removal under conditions more similar to the field, proved the high efficiency of using N-series bacteria in crude oil degradation.
Keywords: Ochrobactrum sp. N1, Brevibacillus parabrevis N2, B. parabrevis N3 and B. parabrevis N4, crude oil degradation.
002-Chrzanowski L, Dziadas M, Lawniczak L, Cyplik P, Bialas W, Szulc A, Lisiecki P, Jelen H. Institute of Chemical Technology and Engineering, Poznan University of Technology, Pl. M. Sklodowskiej-Curie 2, 60-965 Poznan, Poland. Biodegradation of rhamnolipids in liquid cultures: Effects of biosurfactant dissipation on diesel fuel/B20 blend biodegradation efficiency and bacterial community composition. Bioresource Technology, 2012, 328 – 35.
Bacterial utilization of rhamnolipids during biosurfactant-supplemented biodegradation of diesel and B20 (20% biodiesel and 80% diesel v/v) fuels was evaluated under conditions with full aeration or with nitrate and nitrite as electron acceptors. Rhamnolipid-induced changes in community dynamics were assessed by employing real-time PCR and the ddCt method for relative quantification. The experiments with rhamnolipids at 150 mg/l, approx. double critical micelle concentration (CMC) and diesel oil confirmed that rhamnolipids were readily degraded by a soil-isolated consortium of hydrocarbon degraders in all samples, under both aerobic and nitrate-reducing conditions. The presence of rhamnolipids increased the dissipation rates for B20 constituents under aerobic conditions, but did not influence the biodegradation rate of pure diesel. No effect was observed under nitrate-reducing conditions. The biodegradation of rhamnolipids did not favor the growth of any specific consortium member, which proved that the employed biosurfactant did not interfere with the microbial equilibrium during diesel/biodiesel biodegradation
Keywords: Biosurfactant, Biodegradation of diesel, Rhamnolipids.