Biodispersants are detergent-like products made by dissolving biosurfactants in solvents. Biosurfactants, comparing with their chemical counterparts, have advantages of lower eco-toxicity, as well as higher biodegradability and stability. Biodispersants have the great potential to be applied as the reagent for offshore oil spill response. However, relevant topics were rarely reported in literature due to the extremely limited biodispersants available and the high cost of biosurfactant production.udThis study thus tried to fill the research gap through enhancing the producting of biosurfactants so as to decrease the cost and generating biodispersant products for oil spill response. The biosurfactants were produced by Rhodococcus erythropolis sp. SB-1A, a strain isolated from the North Atlantic Ocean. Effects of culturing conditions including the carbon source, the nitrogen source, pH and salinity were investigated through the One-factor-at-a-time (OFAT) experiments. Surface tension and the reciprocal of critical micelle concentration (CMC-1) of the cell-free culture were monitored periodically. A kinetics model was established to represent the time course of biosurfactant production. Under the determined culturing conditions (3.5 v/v% N-hexadecane, 0.7 g/L NH4NO3, pH 7 and 26 g/L NaCl), the surface tension of culture mediums was reduced by 40 dynes/cm with a CMC-1 of 11.9 after 40 hours of cultivation. The produced biosurfactants were further characterized. Results indicated that the total carbohydrate content in 1 g of biosurfactants was 8.4 mg in term of D-glucose, and the total lipid content in 1 g of biosurfactants was 11.6 mg in term of Palmitic acid.udMultiple solvents were selected to mixed with the biosurfactants, respectively, to obtain the biodispersants. The solvents were screened based on their toxicity and the effectiveness of relevant dispersants generated. The final formula of the biodispersant was determined as 16.7%/ 83.3% (biosurfactants/ PEG 400). The biodispersant-based dispersion was further examined using a motor oil sample and a crude oil sample. The performance was compared with the commercial chemical dispersant Corexit 9527. Results showed that compared with Corexit 9527, the biodispersant could achieve a compatible dispersant effectiveness (DE) when treating the motor oil and a higher DE for treating the crude oil. Through the biodegradation test, 45% of the biodispersed crude oil was biodegraded by the biodispersant assisted dispersion after 28 days of dispersion treatment without spiking any oil-degrading bacteria. The toxicity of the biodispersed oil was reduced by 50% after 28 days. The research outputs provided an evidence for applying biodispersants as a promising alternative reagent for offshore oil spill response.
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机译：生物分散剂是通过将生物表面活性剂溶解在溶剂中制成的类似洗涤剂的产品。与化学表面活性剂相比，生物表面活性剂具有较低的生态毒性以及较高的生物降解性和稳定性。生物分散剂作为海上溢油应急反应的试剂具有巨大的潜力。但是，由于可用的生物分散剂极为有限且生物表面活性剂的生产成本较高，因此相关文献很少在文献中报道。 ud因此，本研究试图通过增强生物表面活性剂的生产来填补研究空白，从而降低成本并生产生物分散剂产品。应对溢油。生物表面活性剂是由红球红球菌（Rhodococcus erythropolis sp。）生产的。 SB-1A，从北大西洋分离的菌株。通过一次一因素（OFAT）实验研究了培养条件对碳源，氮源，pH和盐度的影响。定期监测无细胞培养物的表面张力和临界胶束浓度（CMC-1）的倒数。建立了动力学模型来代表生物表面活性剂生产的时间过程。在确定的培养条件下（3.5 v / v％N-十六烷，0.7 g / L NH4NO3，pH 7和26 g / L NaCl），培养基的表面张力降低40达因/厘米，CMC-1为培养40小时后为11.9。所产生的生物表面活性剂被进一步表征。结果表明，按D-葡萄糖计，每1克生物表面活性剂的总碳水化合物含量为8.4 mg，按棕榈酸计，每1g生物表面活性剂的总脂质含量为11.6 mg。生物表面活性剂，分别获得生物分散剂。根据溶剂的毒性和产生的相关分散剂的有效性来筛选溶剂。确定了生物分散剂的最终配方为16.7％/ 83.3％（生物表面活性剂/ PEG 400）。使用机油样品和原油样品进一步检查基于生物分散剂的分散体。将其性能与市售化学分散剂Corexit 9527进行了比较。结果表明，与Corexit 9527相比，该生物分散剂在处理机油时可以达到相容的分散剂效果（DE），而在处理原油时可以达到更高的DE效果。通过生物降解测试，分散处理28天后，通过生物分散剂辅助的分散体将45％的生物分散原油进行了生物降解，而不会产生任何降解油的细菌。 28天后，生物分散油的毒性降低了50％。研究结果为将生物分散剂用作海上溢油应急反应的有希望替代试剂提供了证据。
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